bursty cycle rate test online

adapters-api/src/main/java/io/nosqlbench/adapters/api/evalcontext/GroovyCycleFunction.java

@@ -20,8 +20,8 @@ import groovy.lang.Binding;
 import groovy.lang.GroovyShell;
 import groovy.lang.Script;
 import io.nosqlbench.adapters.api.activityimpl.BaseOpDispenser;
-import io.nosqlbench.api.extensions.SandboxExtensionFinder;
 import io.nosqlbench.api.extensions.ScriptingExtensionPluginInfo;
+import io.nosqlbench.engine.core.lifecycle.scenario.execution.BundledExtensions;
 import io.nosqlbench.virtdata.core.bindings.Bindings;
 import io.nosqlbench.virtdata.core.bindings.BindingsTemplate;
 import io.nosqlbench.virtdata.core.templates.BindPoint;
@@ -75,7 +75,7 @@ public class GroovyCycleFunction<T> implements CycleFunction<T> {
     }
 
     private void addServices() {
-        for (final ScriptingExtensionPluginInfo<?> extensionDescriptor : SandboxExtensionFinder.findAll()) {
+        for (final ScriptingExtensionPluginInfo<?> extensionDescriptor : BundledExtensions.findAll()) {
             staticImports.addAll(extensionDescriptor.autoImportStaticMethodClasses());
             if (!extensionDescriptor.isAutoLoading()) {
                 logger.info(() -> "Not loading " + extensionDescriptor + ", autoloading is false");

engine-api/src/main/java/io/nosqlbench/engine/api/activityapi/ratelimits/simrate/SimRate.java

@@ -81,9 +81,16 @@ public class SimRate extends NBBaseComponent implements RateLimiter, Thread.Unca
     public SimRate(NBComponent parent, SimRateSpec spec) {
         super(parent, NBLabels.forKV());
         this.spec = spec;
+        initMetrics();
         startFiller();
     }
 
+    private void initMetrics() {
+        create().gauge("cycles_waittime",() -> (double)getWaitTimeDuration().get(ChronoUnit.NANOS));
+        create().gauge("_config_cyclerate", () -> spec.opsPerSec);
+        create().gauge("_config_burstrate", () -> spec.burstRatio);
+    }
+
     public long refill() {
         try {
 

engine-api/src/main/java/io/nosqlbench/engine/api/activityimpl/SimpleActivity.java

@@ -116,7 +116,7 @@ public class SimpleActivity extends NBBaseComponent implements Activity {
 
     @Override
     public synchronized void initActivity() {
-//        initOrUpdateRateLimiters(this.activityDef);
+        initOrUpdateRateLimiters(this.activityDef);
     }
 
     public synchronized NBErrorHandler getErrorHandler() {
@@ -307,7 +307,6 @@ public class SimpleActivity extends NBBaseComponent implements Activity {
 
     public synchronized void initOrUpdateRateLimiters(ActivityDef activityDef) {
 
-
         activityDef.getParams().getOptionalNamedParameter("striderate")
                 .map(StrideRateSpec::new).ifPresent(sr -> this.onEvent(new ParamChange<>(sr)));
 

engine-api/src/main/java/io/nosqlbench/engine/api/scripting/ScriptEnvBuffer.java

@@ -43,7 +43,7 @@ public class ScriptEnvBuffer extends SimpleScriptContext {
             synchronized(this) {
                 if (stdoutBuffer==null) {
                     Writer superWriter = super.getWriter();
-                    stdoutBuffer = new DiagWriter(superWriter, new InterjectingCharArrayWriter(" stdout  "));
+                    stdoutBuffer = new DiagWriter(new InterjectingCharArrayWriter(" stdout  "),superWriter);
                 }
             }
         }
@@ -56,7 +56,7 @@ public class ScriptEnvBuffer extends SimpleScriptContext {
             synchronized(this) {
                 if (stderrBuffer==null) {
                     Writer superErrorWriter = super.getErrorWriter();
-                    stderrBuffer = new DiagWriter(superErrorWriter, new InterjectingCharArrayWriter(" stderr "));
+                    stderrBuffer = new DiagWriter(new InterjectingCharArrayWriter(" stderr "),superErrorWriter);
                 }
             }
         }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/ExecutionMetricsResult.java

@@ -23,7 +23,7 @@ import com.codahale.metrics.MetricFilter;
 import io.nosqlbench.api.engine.metrics.instruments.*;
 import io.nosqlbench.api.engine.metrics.reporters.ConsoleReporter;
 import io.nosqlbench.api.engine.metrics.reporters.Log4JMetricsReporter;
-import io.nosqlbench.components.NBBuilders;
+import io.nosqlbench.components.NBCreators;
 import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.components.NBComponentTraversal;
 import io.nosqlbench.components.NBFinders;
@@ -63,7 +63,7 @@ public class ExecutionMetricsResult extends ExecutionResult {
     public String getMetricsSummary(NBComponent component) {
         final ByteArrayOutputStream os = new ByteArrayOutputStream();
         try (final PrintStream ps = new PrintStream(os)) {
-            final NBBuilders.ConsoleReporterBuilder builder = new NBBuilders.ConsoleReporterBuilder(component, ps);
+            final NBCreators.ConsoleReporterBuilder builder = new NBCreators.ConsoleReporterBuilder(component, ps);
             final Set<MetricAttribute> disabled = new HashSet<>(ExecutionMetricsResult.INTERVAL_ONLY_METRICS);
             if (60000 > this.getElapsedMillis()) disabled.addAll(ExecutionMetricsResult.OVER_ONE_MINUTE_METRICS);
             builder.disabledMetricAttributes(disabled);
@@ -90,7 +90,7 @@ public class ExecutionMetricsResult extends ExecutionResult {
         ExecutionResult.logger.debug("-- active data on this last report. (The workload has already stopped.) Record   --");
         ExecutionResult.logger.debug("-- metrics to an external format to see values for each reporting interval.      --");
         ExecutionResult.logger.debug("-- BEGIN METRICS DETAIL --");
-        final Log4JMetricsReporter reporter = new NBBuilders.Log4jReporterBuilder(component)
+        final Log4JMetricsReporter reporter = new NBCreators.Log4jReporterBuilder(component)
             .withLoggingLevel(Log4JMetricsReporter.LoggingLevel.DEBUG)
             .filter(MetricFilter.ALL)
             .outputTo(ExecutionResult.logger)

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/NBDefaultSceneFixtures.java

@@ -18,7 +18,6 @@ package io.nosqlbench.engine.core.lifecycle.scenario.context;
 
 import io.nosqlbench.api.config.standard.TestComponent;
 import io.nosqlbench.components.NBComponent;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 import io.nosqlbench.engine.core.lifecycle.session.NBSession;
 
 import java.io.*;
@@ -61,58 +60,44 @@ public class NBDefaultSceneFixtures implements NBSceneFixtures {
      * Extensions provide additional scripting capabilities which are not provided by the
      * scripting or other runtimes, or new ways of tapping into extant features.
      */
-    private Extensions extensions;
 
     private PrintWriter out;
     private PrintWriter err;
 
     private Reader in;
 
-    public NBDefaultSceneFixtures(ScenarioParams params, NBComponent parent, ScenarioActivitiesController controller, Extensions extensions, PrintWriter out, PrintWriter err, Reader in) {
+    public NBDefaultSceneFixtures(ScenarioParams params, ScenarioActivitiesController controller, PrintWriter out, PrintWriter err, Reader in) {
         this.params = params;
-        this.session = parent;
         this.controller = controller;
-        this.extensions = extensions;
         this.out = out;
         this.err = err;
         this.in = in;
     }
 
-    public static NBSceneFixtures ofDefault(String name) {
+//    public static NBSceneFixtures ofDefault(String name) {
-        return new NBDefaultSceneFixtures(
+//        return new NBDefaultSceneFixtures(
-            new ScenarioParams(),
+//            new ScenarioParams(),
-            new NBSession(
+//            new NBSession(
-                new TestComponent("scene", name), "scene~"+name
+//                new TestComponent("scene", name), "scene~"+name
-            ),
+//            ),
-            new ScenarioActivitiesController(),
+//            new ScenarioActivitiesController(),
-            Extensions.ofNone(),
+//            new PrintWriter(System.out),
-            new PrintWriter(System.out),
+//            new PrintWriter(System.err),
-            new PrintWriter(System.err),
+//            new InputStreamReader(System.in)
-            new InputStreamReader(System.in)
+//        );
-        );
+//    }
-    }
+//
-
 
     @Override
     public ScenarioParams params() {
         return params;
     }
 
-    @Override
-    public NBComponent component() {
-        return session;
-    }
-
     @Override
     public ScenarioActivitiesController controller() {
         return controller;
     }
 
-    @Override
-    public Extensions extensions() {
-        return extensions;
-    }
-
     @Override
     public PrintWriter out() {
         return out;

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/NBSceneBuffer.java

@@ -21,7 +21,6 @@ import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.engine.api.scripting.DiagReader;
 import io.nosqlbench.engine.api.scripting.DiagWriter;
 import io.nosqlbench.engine.api.scripting.InterjectingCharArrayWriter;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 
 import java.io.PrintWriter;
 import java.io.Reader;
@@ -35,6 +34,7 @@ public class NBSceneBuffer implements NBSceneFixtures {
         virtual,
         traced
     }
+
     private final IOType iotype;
     private DiagWriter stdoutBuffer;
     private DiagWriter stderrBuffer;
@@ -46,8 +46,8 @@ public class NBSceneBuffer implements NBSceneFixtures {
 
         switch (iotype) {
             case traced:
-                stdoutBuffer = new DiagWriter(fixtures.out(), new InterjectingCharArrayWriter(" stdout "));
+                stdoutBuffer = new DiagWriter(new InterjectingCharArrayWriter(" stdout "), fixtures.out());
-                stderrBuffer = new DiagWriter(fixtures.err(), new InterjectingCharArrayWriter(" stderr "));
+                stderrBuffer = new DiagWriter(new InterjectingCharArrayWriter(" stderr "), fixtures.err());
                 stdinBuffer = new DiagReader(fixtures.in(), "  stdin ");
                 break;
             case virtual:
@@ -58,7 +58,7 @@ public class NBSceneBuffer implements NBSceneFixtures {
             case connected:
                 stdoutBuffer = new DiagWriter(fixtures.out());
                 stderrBuffer = new DiagWriter(fixtures.err());
-                stdinBuffer = new DiagReader(fixtures.in(), "  stdin ");
+                stdinBuffer = new DiagReader(fixtures.in());
                 break;
 
         }
@@ -74,21 +74,11 @@ public class NBSceneBuffer implements NBSceneFixtures {
         return fixtures.params();
     }
 
-    @Override
-    public NBComponent component() {
-        return fixtures.component();
-    }
-
     @Override
     public ScenarioActivitiesController controller() {
         return fixtures.controller();
     }
 
-    @Override
-    public Extensions extensions() {
-        return fixtures.extensions();
-    }
-
     @Override
     public PrintWriter out() {
         return stdoutBuffer;
@@ -105,19 +95,19 @@ public class NBSceneBuffer implements NBSceneFixtures {
     }
 
     public String getIOLog() {
-        return this.stdoutBuffer.getTimedLog()+this.stderrBuffer.getTimedLog();
+        return this.stdoutBuffer.getTimedLog() + this.stderrBuffer.getTimedLog();
     }
 
     public NBSceneFixtures asFixtures() {
         return (NBSceneFixtures) this;
     }
 
-    public static NBSceneBuffer init(String name) {
-        TestComponent root = new TestComponent("scene", "self");
-        return new NBSceneBuffer(NBDefaultSceneFixtures.ofDefault(name));
-    }
 
-    public static SceneBuilderFacets.WantsContext builder() {
+    public static SceneBuilderFacets.WantsController builder() {
         return new SceneBuilder();
     }
+
+    public static NBSceneBuffer traced(NBComponent component) {
+        return builder().tracedIO().build(component);
+    }
 }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/NBSceneFixtures.java

@@ -17,7 +17,6 @@
 package io.nosqlbench.engine.core.lifecycle.scenario.context;
 
 import io.nosqlbench.components.NBComponent;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 
 import java.io.PrintWriter;
 import java.io.Reader;
@@ -25,20 +24,13 @@ import java.io.Reader;
 public interface NBSceneFixtures {
     ScenarioParams params();
 
-    NBComponent component();
-
     ScenarioActivitiesController controller();
 
-    Extensions extensions();
-
     PrintWriter out();
 
     PrintWriter err();
 
     Reader in();
 
-    public static NBSceneFixtures NEW(String sceneName) {
-        return NBDefaultSceneFixtures.ofDefault(sceneName);
-    }
 
 }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/ScenarioActivitiesController.java

@@ -52,14 +52,6 @@ public class ScenarioActivitiesController extends NBBaseComponent {
 
     private final ExecutorService executorService;
 
-    public ScenarioActivitiesController() {
-        super(new TestComponent("test","test"));
-        this.activityLoader = new ActivityLoader();
-        ActivitiesExceptionHandler exceptionHandler = new ActivitiesExceptionHandler(this);
-        IndexedThreadFactory indexedThreadFactory = new IndexedThreadFactory("ACTIVITY", exceptionHandler);
-        this.executorService = Executors.newVirtualThreadPerTaskExecutor();
-    }
-
     public ScenarioActivitiesController(NBComponent parent) {
         super(parent);
         this.activityLoader = new ActivityLoader();

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/SceneBuilder.java

@@ -19,7 +19,6 @@ package io.nosqlbench.engine.core.lifecycle.scenario.context;
 
 
 import io.nosqlbench.components.NBComponent;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 
 import java.io.BufferedReader;
 import java.io.InputStreamReader;
@@ -30,27 +29,17 @@ import java.util.Map;
 public class SceneBuilder implements SceneBuilderFacets.ALL {
     private Map<String,String> params = Map.of();
     private ScenarioActivitiesController controller;
-    private Extensions extensions;
     private PrintWriter out = new PrintWriter(System.out);
     private PrintWriter err = new PrintWriter(System.err);
     private Reader in = new InputStreamReader(System.in);
-    private NBComponent component;
+    private NBSceneBuffer.IOType iotype = NBSceneBuffer.IOType.traced;
-    private NBSceneBuffer.IOType iotype;
 
 
-    @Override
+    public NBSceneBuffer build(NBComponent forScenario) {
-    public SceneBuilder component(NBComponent component) {
-        this.component = component;
-        return this;
-    }
-
-    public NBSceneBuffer build() {
         NBDefaultSceneFixtures fixtures =
             new NBDefaultSceneFixtures(
                 ScenarioParams.of(this.params),
-                this.component,
+                ((this.controller!=null) ? this.controller : new ScenarioActivitiesController(forScenario)),
-                ((this.controller!=null) ? this.controller : new ScenarioActivitiesController(component)),
-                this.extensions,
                 this.out,
                 this.err,
                 this.in);
@@ -71,7 +60,7 @@ public class SceneBuilder implements SceneBuilderFacets.ALL {
     }
 
     @Override
-    public SceneBuilder err(PrintWriter err) {
+    public SceneBuilderFacets.WantsParams err(PrintWriter err) {
         this.err = err;
         return this;
     }
@@ -83,12 +72,6 @@ public class SceneBuilder implements SceneBuilderFacets.ALL {
 
     }
 
-    @Override
-    public SceneBuilder extensions(Extensions extensions) {
-        this.extensions = extensions;
-        return this;
-    }
-
     @Override
     public SceneBuilder params(Map<String, String> params) {
         this.params=params;
@@ -96,19 +79,19 @@ public class SceneBuilder implements SceneBuilderFacets.ALL {
     }
 
     @Override
-    public SceneBuilderFacets.WantsExtensions virtualIO() {
+    public SceneBuilderFacets.WantsParams virtualIO() {
         this.iotype= NBSceneBuffer.IOType.virtual;
         return this;
     }
 
     @Override
-    public SceneBuilderFacets.WantsExtensions connectedIO() {
+    public SceneBuilderFacets.WantsParams connectedIO() {
         this.iotype = NBSceneBuffer.IOType.connected;
         return this;
     }
 
     @Override
-    public SceneBuilderFacets.WantsExtensions tracedIO() {
+    public SceneBuilderFacets.WantsParams tracedIO() {
         this.iotype=NBSceneBuffer.IOType.traced;
         return this;
     }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/context/SceneBuilderFacets.java

@@ -19,7 +19,6 @@ package io.nosqlbench.engine.core.lifecycle.scenario.context;
 
 
 import io.nosqlbench.components.NBComponent;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 
 import java.io.PrintWriter;
 import java.io.Reader;
@@ -27,9 +26,7 @@ import java.util.Map;
 
 public interface SceneBuilderFacets {
     public interface ALL extends
-        WantsContext,
         WantsController,
-        WantsExtensions,
         WantsStderr,
         WantsStdout,
         WantsStdin,
@@ -39,10 +36,6 @@ public interface SceneBuilderFacets {
     }
 
 
-    public interface WantsContext {
-        public WantsController component(NBComponent component);
-    }
-
     public interface WantsController extends WantsStdin, WantsIoType {
         public WantsStdin controller(ScenarioActivitiesController controller);
     }
@@ -57,7 +50,7 @@ public interface SceneBuilderFacets {
     }
 
     public interface WantsStderr extends CanBuild {
-        public WantsExtensions err(PrintWriter err);
+        public WantsParams err(PrintWriter err);
     }
 
     public interface WantsIoType extends CanBuild {
@@ -65,23 +58,19 @@ public interface SceneBuilderFacets {
          * If you want the stdin, stdout, stderr streams to be contained only within the scenario's
          * execution environment, not connected to the outside world, do this.
          */
-        public WantsExtensions virtualIO();
+        public WantsParams virtualIO();
 
         /**
          * If you want to connect stdin, stdout, stderr streams to the system in, out and error streams,
          * do this.
          */
-        public WantsExtensions connectedIO();
+        public WantsParams connectedIO();
 
         /**
          * If you want to connect the console IO streams to the outside world, but also capture them for
          * diagnostics or other purposes, do this.
          */
-        public WantsExtensions tracedIO();
+        public WantsParams tracedIO();
-    }
-
-    public interface WantsExtensions extends CanBuild {
-        public WantsParams extensions(Extensions extensions);
     }
 
     public interface WantsParams extends CanBuild {
@@ -89,7 +78,7 @@ public interface SceneBuilderFacets {
     }
 
     public interface CanBuild {
-        NBSceneBuffer build();
+        NBSceneBuffer build(NBComponent forComponent);
     }
 
 }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/direct/SCBaseScenario.java

@@ -20,7 +20,6 @@ import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.engine.core.lifecycle.scenario.context.ScenarioActivitiesController;
 import io.nosqlbench.engine.core.lifecycle.scenario.context.NBSceneFixtures;
 import io.nosqlbench.engine.core.lifecycle.scenario.context.ScenarioParams;
-import io.nosqlbench.engine.core.lifecycle.scenario.execution.Extensions;
 import io.nosqlbench.engine.core.lifecycle.scenario.execution.NBScenario;
 
 import java.io.PrintWriter;
@@ -28,13 +27,11 @@ import java.io.Reader;
 import java.io.Writer;
 
 public abstract class SCBaseScenario extends NBScenario {
-    protected NBComponent component;
     protected Reader stdin;
     protected PrintWriter stdout;
     protected Writer stderr;
     protected ScenarioActivitiesController controller;
     protected ScenarioParams params;
-    protected Extensions extensions;
 
     public SCBaseScenario(NBComponent parentComponent, String scenarioName) {
         super(parentComponent, scenarioName);
@@ -42,14 +39,17 @@ public abstract class SCBaseScenario extends NBScenario {
 
     @Override
     protected final void runScenario(NBSceneFixtures shell) {
-        this.component = shell.component();
         this.stdin = shell.in();
         this.stdout = shell.out();
         this.stderr = shell.err();
         this.controller = shell.controller();
         this.params = shell.params();
-        this.extensions = shell.extensions();
+        try {
             invoke();
+        } catch (Exception e) {
+            stdout.println(e.toString());
+            throw e;
+        }
     }
 
     /**
@@ -62,7 +62,6 @@ public abstract class SCBaseScenario extends NBScenario {
      *     <LI>stdout, stderr</LI>- a {@link PrintWriter}; This can be buffered virtually, attached to {@link System#out} and {@link System#err} or both for IO tracing.</LI>
      *     <LI>controller - A dedicated {@link ScenarioActivitiesController} which can be used to define, start, top, and interact with activities.</LI>
      *     <LI>params - The {@link ScenarioParams} which have been passed to this scenario.</LI>
-     *     <LI>extensions - A dedicated ahndle to the {@link Extensions} service.</LI>
      *     <LI><EM>all component services</EM> as this scenario IS a component. This includes all implemented methods in any of the {@link NBComponent} sub-interfaces.</EM>
      *     </LI>
      * </UL>

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/execution/ScenarioResult.java

@@ -46,6 +46,7 @@ public class ScenarioResult {
         }
     }
     public void exitWithCode() {
+        System.out.print(getIOLog());
         if (exception!=null) {
             System.exit(2);
         }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/execution/ScenariosExecutor.java

@@ -69,11 +69,9 @@ public class ScenariosExecutor extends NBBaseComponent {
     @NotNull
     private NBSceneBuffer getNbSceneBuffer(Map<String, String> params) {
         return NBSceneBuffer.builder()
-            .component(this.getParent())
             .tracedIO()
-            .extensions(loadExtensions())
             .params(params)
-            .build();
+            .build(parent);
     }
 
     @Override
@@ -269,30 +267,6 @@ public class ScenariosExecutor extends NBBaseComponent {
         this.stoppingException = new RuntimeException("Error in scenario thread " + t.getName(), e);
     }
 
-    private Extensions loadExtensions() {
-        Extensions extensions = new Extensions();// TODO: Load component oriented extensions into here
-
-//        for (final ScriptingExtensionPluginInfo<?> extensionDescriptor : SandboxExtensionFinder.findAll()) {
-//            if (!extensionDescriptor.isAutoLoading()) {
-//                this.logger.info(() -> "Not loading " + extensionDescriptor + ", autoloading is false");
-//                continue;
-//            }
-//
-//            final Logger extensionLogger =
-//                LogManager.getLogger("extensions." + extensionDescriptor.getBaseVariableName());
-//            final Object extensionObject = extensionDescriptor.getExtensionObject(
-//                extensionLogger,
-//                metricRegistry,
-//                this.scriptEnv
-//            );
-//            ScenarioMetadataAware.apply(extensionObject, this.getScenarioMetadata());
-//            this.logger.trace(() -> "Adding extension object:  name=" + extensionDescriptor.getBaseVariableName() +
-//                " class=" + extensionObject.getClass().getSimpleName());
-//            this.scriptEngine.put(extensionDescriptor.getBaseVariableName(), extensionObject);
-//        }
-        return extensions;
-    }
-
     public ScenarioResult run(NBScenario scenario, Map<String,String> params) {
         return scenario.apply(getNbSceneBuffer(params));
     }

engine-core/src/main/java/io/nosqlbench/engine/core/lifecycle/session/NBSession.java

@@ -21,6 +21,7 @@ import io.nosqlbench.api.spi.SimpleServiceLoader;
 import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.components.NBBaseComponent;
 import io.nosqlbench.components.NBComponentSubScope;
+import io.nosqlbench.components.decorators.NBTokenWords;
 import io.nosqlbench.engine.cli.BasicScriptBuffer;
 import io.nosqlbench.engine.cli.Cmd;
 import io.nosqlbench.engine.cli.ScriptBuffer;
@@ -47,7 +48,7 @@ import java.util.function.Function;
  * on.
  * All NBScenarios are run within an NBSession.
  */
-public class NBSession extends NBBaseComponent implements Function<List<Cmd>, ExecutionResult> {
+public class NBSession extends NBBaseComponent implements Function<List<Cmd>, ExecutionResult>, NBTokenWords {
     private final static Logger logger = LogManager.getLogger(NBSession.class);
     private final String sessionName;
 

engine-core/src/test/java/io/nosqlbench/engine/core/lifecycle/scenario/context/SceneBuilderTest.java

@@ -1,37 +0,0 @@
-package io.nosqlbench.engine.core.lifecycle.scenario.context;
-
-/*
- * Copyright (c) 2022 nosqlbench
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- * 
- *   http://www.apache.org/licenses/LICENSE-2.0
- * 
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- */
-
-
-import io.nosqlbench.api.config.standard.TestComponent;
-import org.junit.jupiter.api.Test;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-class SceneBuilderTest {
-
-    @Test
-    public void testBuildDefaultScene() {
-        NBSceneBuffer buffer = NBSceneBuffer.builder()
-            .component(new TestComponent("test", "test"))
-            .tracedIO()
-            .build();
-    }
-
-
-}

engine-extensions/src/main/java/io/nosqlbench/engine/extensions/example/ExamplePluginData.java

@@ -21,7 +21,7 @@ import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.nb.annotations.Service;
 import org.apache.logging.log4j.Logger;
 
-@Service(value = ScriptingExtensionPluginInfo.class, selector = "adder")
+@Service(value = ScriptingExtensionPluginInfo.class, selector = "example")
 public class ExamplePluginData implements ScriptingExtensionPluginInfo<ExamplePlugin> {
 
     @Override

nb-api/src/main/java/io/nosqlbench/api/engine/metrics/reporters/Log4JMetricsReporter.java

@@ -19,7 +19,7 @@ package io.nosqlbench.api.engine.metrics.reporters;
 import com.codahale.metrics.*;
 import io.nosqlbench.api.engine.metrics.instruments.*;
 import io.nosqlbench.api.labels.NBLabels;
-import io.nosqlbench.components.NBBuilders;
+import io.nosqlbench.components.NBCreators;
 import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.components.NBFinders;
 import io.nosqlbench.components.PeriodicTaskComponent;
@@ -37,7 +37,7 @@ import java.util.concurrent.TimeUnit;
 public class Log4JMetricsReporter extends PeriodicTaskComponent {
 
     public enum LoggingLevel { TRACE, DEBUG, INFO, WARN, ERROR }
-    private final NBBuilders.LoggerProxy loggerProxy;
+    private final NBCreators.LoggerProxy loggerProxy;
     private final Marker marker;
     private final TimeUnit rateUnit = TimeUnit.NANOSECONDS;
     private final TimeUnit durationUnit = TimeUnit.NANOSECONDS;
@@ -45,7 +45,7 @@ public class Log4JMetricsReporter extends PeriodicTaskComponent {
     private final long rateFactor = TimeUnit.NANOSECONDS.toSeconds(1);
 
     public Log4JMetricsReporter(final NBComponent component,
-                                final NBBuilders.LoggerProxy loggerProxy,
+                                final NBCreators.LoggerProxy loggerProxy,
                                 final Marker marker,
                                 final MetricFilter filter,
                                 final NBLabels extraLabels,

nb-api/src/main/java/io/nosqlbench/api/extensions/SandboxExtensionFinder.java

@@ -1,42 +0,0 @@
-/*
- * Copyright (c) 2022-2023 nosqlbench
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.nosqlbench.api.extensions;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.ServiceLoader;
-
-public class SandboxExtensionFinder {
-
-    private final static List<ScriptingExtensionPluginInfo<?>> extensionDescriptors = new ArrayList<>();
-
-    public static List<ScriptingExtensionPluginInfo<?>> findAll() {
-        if (extensionDescriptors.isEmpty()) {
-            synchronized (SandboxExtensionFinder.class) {
-                if (extensionDescriptors.isEmpty()) {
-                    ServiceLoader<ScriptingExtensionPluginInfo> loader =
-                            ServiceLoader.load(ScriptingExtensionPluginInfo.class);
-                    loader.iterator().forEachRemaining(extensionDescriptors::add);
-                }
-            }
-        }
-
-        return Collections.unmodifiableList(extensionDescriptors);
-
-    }
-}

nb-api/src/main/java/io/nosqlbench/api/metadata/ScenarioMetadataAware.java

@@ -1,37 +0,0 @@
-/*
- * Copyright (c) 2022 nosqlbench
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.nosqlbench.api.metadata;
-
-/**
- * Where supported, the following named fields are injected into object which
- * implement this interface:
- * <UL>
- *     <LI>SCENARIO_NAME - The full scenario name, used for logging, metrics, etc</LI>
- *     <LI>STARTED_AT_MILLIS - The millisecond timestamp used to create the scenario name</LI>
- *     <LI>SYSTEM_ID - A stable identifier based on the available ip addresses</LI></LK>
- *     <LI>SYSTEM_FINGERPRINT - a stable and pseudonymous identifier based on SYSTEM_ID</LI>
- * </UL>
- */
-public interface ScenarioMetadataAware {
-    void setScenarioMetadata(ScenarioMetadata metadata);
-
-    static void apply(Object target, ScenarioMetadata metadata) {
-        if (target instanceof ScenarioMetadataAware) {
-            ((ScenarioMetadataAware)target).setScenarioMetadata(metadata);
-        }
-    }
-}

nb-api/src/main/java/io/nosqlbench/api/s3uploader/S3Uploader.java

@@ -24,7 +24,6 @@ import com.amazonaws.services.s3.transfer.TransferManagerBuilder;
 import io.nosqlbench.addins.s3.s3urlhandler.S3ClientCache;
 import io.nosqlbench.addins.s3.s3urlhandler.S3UrlFields;
 import io.nosqlbench.api.metadata.ScenarioMetadata;
-import io.nosqlbench.api.metadata.ScenarioMetadataAware;
 import io.nosqlbench.api.system.NBEnvironment;
 import io.nosqlbench.components.NBBaseComponent;
 import io.nosqlbench.components.NBComponent;
@@ -39,7 +38,7 @@ import java.nio.file.Path;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
-public class S3Uploader extends NBBaseComponent implements ScenarioMetadataAware {
+public class S3Uploader extends NBBaseComponent {
     private ScenarioMetadata scenarioMetadata;
     private final static Logger logger = LogManager.getLogger(S3Uploader.class);
 
@@ -81,11 +80,7 @@ public class S3Uploader extends NBBaseComponent implements ScenarioMetadataAware
 
         Map<String,String> combined = new LinkedHashMap<>(params);
         combined.putAll(scenarioMetadata.asMap());
-        String url = NBEnvironment.INSTANCE.interpolateWithTimestamp(
+        String url = NBEnvironment.INSTANCE.interpolateWithTimestamp(urlTemplate, scenarioMetadata.getStartedAt(), combined)
-            urlTemplate,
-                scenarioMetadata.getStartedAt(),
-                combined
-            )
             .orElseThrow();
         logger.debug(() -> "S3 composite URL is '" + url + "'");
 
@@ -103,8 +98,4 @@ public class S3Uploader extends NBBaseComponent implements ScenarioMetadataAware
         return url;
     }
 
-    @Override
-    public void setScenarioMetadata(ScenarioMetadata metadata) {
-        this.scenarioMetadata = metadata;
-    }
 }

nb-api/src/main/java/io/nosqlbench/components/NBBaseComponent.java

@@ -20,22 +20,23 @@ package io.nosqlbench.components;
 
 import io.nosqlbench.api.engine.metrics.instruments.NBMetric;
 import io.nosqlbench.api.labels.NBLabels;
+import io.nosqlbench.components.decorators.NBTokenWords;
 import io.nosqlbench.components.events.NBEvent;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.util.ArrayList;
+import java.util.*;
-import java.util.List;
 
-public class NBBaseComponent extends NBBaseComponentMetrics implements NBComponent {
+public class NBBaseComponent extends NBBaseComponentMetrics implements NBComponent, NBTokenWords {
     private final static Logger logger = LogManager.getLogger("RUNTIME");
     protected final NBComponent parent;
     protected final NBLabels labels;
     private final List<NBComponent> children = new ArrayList<>();
 
     public NBBaseComponent(NBComponent parentComponent) {
-        this(parentComponent,NBLabels.forKV());
+        this(parentComponent, NBLabels.forKV());
     }
+
     public NBBaseComponent(NBComponent parentComponent, NBLabels componentSpecificLabelsOnly) {
         this.labels = componentSpecificLabelsOnly;
         if (parentComponent != null) {
@@ -78,7 +79,7 @@ public class NBBaseComponent extends NBBaseComponentMetrics implements NBCompone
     @Override
     public NBLabels getLabels() {
         NBLabels effectiveLabels = (this.parent == null ? NBLabels.forKV() : parent.getLabels());
-        effectiveLabels = (this.labels == null ) ? effectiveLabels : effectiveLabels.and(this.labels);
+        effectiveLabels = (this.labels == null) ? effectiveLabels : effectiveLabels.and(this.labels);
         return effectiveLabels;
     }
 
@@ -116,8 +117,8 @@ public class NBBaseComponent extends NBBaseComponentMetrics implements NBCompone
     }
 
     @Override
-    public NBBuilders create() {
+    public NBCreators create() {
-        return new NBBuilders(this);
+        return new NBCreators(this);
     }
 
     @Override
@@ -129,7 +130,7 @@ public class NBBaseComponent extends NBBaseComponentMetrics implements NBCompone
     public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append(getClass().getSimpleName());
-        if (getComponentMetrics().size()>0) {
+        if (!getComponentMetrics().isEmpty()) {
             sb.append(System.lineSeparator()).append("metrics:");
             for (NBMetric componentMetric : getComponentMetrics()) {
                 sb.append(System.lineSeparator()).append("  ").append(componentMetric.toString());
@@ -143,7 +144,9 @@ public class NBBaseComponent extends NBBaseComponentMetrics implements NBCompone
     public void onEvent(NBEvent event) {
         logger.debug(() -> description() + " handling event " + event.toString());
         switch (event) {
-            case UpEvent ue -> { if (parent!=null) parent.onEvent(ue); }
+            case UpEvent ue -> {
+                if (parent != null) parent.onEvent(ue);
+            }
             case DownEvent de -> {
                 for (NBComponent child : children) {
                     child.onEvent(de);
@@ -152,4 +155,25 @@ public class NBBaseComponent extends NBBaseComponentMetrics implements NBCompone
             default -> logger.warn("dropping event " + event);
         }
     }
+
+    @Override
+    public <T> Optional<T> findParentService(Class<T> type) {
+        return findServiceOn(type, this);
+    }
+
+    private <T> Optional<T> findServiceOn(Class<T> type, NBComponent target) {
+        if (type.isAssignableFrom(target.getClass())) {
+            return Optional.of(type.cast(target));
+        } else if (getParent() != null) {
+            return findServiceOn(type, getParent());
+        } else {
+            return Optional.empty();
+        }
+    }
+
+    @Override
+    public Map<String, String> getTokens() {
+        return getLabels().asMap();
+    }
+
 }

nb-api/src/main/java/io/nosqlbench/components/NBBaseComponentMetrics.java

@@ -19,10 +19,7 @@ package io.nosqlbench.components;
 import io.nosqlbench.adapters.api.util.TagFilter;
 import io.nosqlbench.api.engine.metrics.instruments.NBMetric;
 
-import java.util.Collection;
+import java.util.*;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -58,6 +55,26 @@ public class NBBaseComponentMetrics implements NBComponentMetrics {
         return filter.filterLabeled(metrics.values());
     }
 
+    @Override
+    public <T> Collection<? extends T> findComponentMetrics(String pattern, Class<T> type) {
+        if (this.metrics.containsKey(pattern)) {
+            NBMetric metric = metrics.get(pattern);
+            if (type.isAssignableFrom(metric.getClass())) {
+                return List.of(type.cast(metric));
+            }
+        }
+        TagFilter filter = new TagFilter(pattern);
+        List<NBMetric> found = filter.filterLabeled(metrics.values());
+        List<T> foundAndMatching = new ArrayList<>();
+        for (NBMetric metric : found) {
+            if (type.isAssignableFrom(metric.getClass())) {
+                foundAndMatching.add(type.cast(metric));
+            }
+        }
+        return foundAndMatching;
+    }
+
+
     @Override
     public Collection<? extends NBMetric> getComponentMetrics() {
         return metrics.values();

nb-api/src/main/java/io/nosqlbench/components/NBComponent.java

@@ -17,6 +17,7 @@
 package io.nosqlbench.components;
 
 import io.nosqlbench.api.labels.NBLabeledElement;
+import io.nosqlbench.components.decorators.NBProviderSearch;
 
 import java.util.List;
 
@@ -33,7 +34,13 @@ import java.util.List;
  *
  * This interface includes more aspects of above by extension going forward.
  */
-public interface NBComponent extends AutoCloseable, NBLabeledElement, NBComponentMetrics, NBComponentServices, NBComponentEvents {
+public interface NBComponent extends
+    AutoCloseable,
+    NBLabeledElement,
+    NBComponentMetrics,
+    NBComponentServices,
+    NBComponentEvents,
+    NBProviderSearch {
 
     NBComponent EMPTY_COMPONENT = new NBBaseComponent(null);
 

nb-api/src/main/java/io/nosqlbench/components/NBComponentLoader.java

@@ -28,6 +28,10 @@ import java.util.List;
 import java.util.ServiceLoader;
 import java.util.function.BiFunction;
 
+/**
+ * Since we like to use SPI/ServiceLoader, and we can't use the Provider-only interface as
+ * suggested in {@link ServiceLoader}, we have to indirect to the safe ctor from a parent context.
+ */
 public class NBComponentLoader {
     public static <C extends NBComponent> C load(NBComponent parent, String selector, Class<C> clazz) {
         ServiceLoader<C> loader = ServiceLoader.load(clazz);

nb-api/src/main/java/io/nosqlbench/components/NBComponentMetrics.java

@@ -50,5 +50,15 @@ public interface NBComponentMetrics {
         return found.get(0);
     }
 
+    default <T> T findOneComponentMetric(String pattern, Class<T> type) {
+        NBMetric found = findOneComponentMetric(pattern);
+        if (type.isAssignableFrom(found.getClass())) {
+            return type.cast(found);
+        }
+        return null;
+    }
+
     Collection<? extends NBMetric> getComponentMetrics();
+
+    <T> Collection<? extends T> findComponentMetrics(String pattern, Class<T> type);
 }

nb-api/src/main/java/io/nosqlbench/components/NBComponentServices.java

@@ -18,7 +18,7 @@ package io.nosqlbench.components;
 
 public interface NBComponentServices {
 
-    public NBBuilders create();
+    public NBCreators create();
 
     public NBFinders find();
 }

nb-api/src/main/java/io/nosqlbench/components/NBCreators.java

@@ -35,32 +35,27 @@ import io.nosqlbench.api.optimizers.BobyqaOptimizerInstance;
 import io.nosqlbench.api.files.FileAccess;
 import io.nosqlbench.api.labels.NBLabels;
 import io.nosqlbench.api.shutdown.NBShutdownHook;
+import io.nosqlbench.engine.core.lifecycle.scenario.execution.BundledExtensions;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import com.codahale.metrics.MetricAttribute;
 import com.codahale.metrics.MetricFilter;
-import io.nosqlbench.api.csvoutput.CsvOutputPluginWriter;
 import io.nosqlbench.api.engine.metrics.reporters.*;
-import io.nosqlbench.api.files.FileAccess;
-import io.nosqlbench.api.optimizers.BobyqaOptimizerInstance;
 import org.apache.logging.log4j.Marker;
 
 import java.io.PrintStream;
-import java.util.Set;
+import java.util.*;
 
 import java.nio.file.Path;
-import java.util.Arrays;
-import java.util.DoubleSummaryStatistics;
-import java.util.List;
 import java.util.function.Supplier;
 
-public class NBBuilders {
+public class NBCreators {
 
     // TODO: add mandatory sanitize() around all label names and label "name" values
-    private final Logger logger = LogManager.getLogger(NBBuilders.class);
+    private final Logger logger = LogManager.getLogger(NBCreators.class);
     private final NBBaseComponent base;
 
-    public NBBuilders(NBBaseComponent base) {
+    public NBCreators(NBBaseComponent base) {
         this.base = base;
     }
 
@@ -398,4 +393,11 @@ public class NBBuilders {
         }
     }
 
+    public <T> T requiredExtension(String name, Class<T> type) {
+        return new BundledExtensions(base)
+            .load(name, type)
+            .orElseThrow(
+                () -> new RuntimeException("unable to load extension with name '" + name + "' and type '" + type.getSimpleName() + "'")
+            );
+    }
 }

nb-api/src/main/java/io/nosqlbench/components/NBFinders.java

@@ -17,8 +17,10 @@
 package io.nosqlbench.components;
 
 import io.nosqlbench.api.engine.metrics.instruments.*;
+import org.apache.commons.text.diff.StringsComparator;
 
 import java.util.ArrayList;
+import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
 
@@ -45,14 +47,16 @@ public class NBFinders {
             System.out.println(NBComponentFormats.formatAsTree(base));
             throw new RuntimeException("unable to find metric with pattern '" + pattern + "'");
         }
-        if (clazz.isAssignableFrom(found.getClass())) {
+        if (clazz.isInstance(found.getClass())) {
+            return clazz.cast(found);
+        } else if (clazz.isAssignableFrom(found.getClass())) {
             return clazz.cast(found);
         } else {
             throw new RuntimeException(
                 "found metric with pattern '" + pattern + "'" +
                     ", but it was type "
                     + found.getClass().getSimpleName() + " (not a "
-                    + clazz.getSimpleName() +")"
+                    + clazz.getSimpleName() + ")"
             );
         }
     }
@@ -123,6 +127,20 @@ public class NBFinders {
         return found;
     }
 
+    private <T> List<T> metricsInTree(String pattern, Class<T> type) {
+        if (pattern.isEmpty()) {
+            throw new RuntimeException("non-empty predicate is required for this form. Perhaps you wanted metricsInTree()");
+        }
+        Iterator<NBComponent> tree = NBComponentTraversal.traverseBreadth(base);
+        List<T> found = new ArrayList<>();
+        while (tree.hasNext()) {
+            NBComponent c = tree.next();
+            found.addAll(c.findComponentMetrics(pattern,type));
+        }
+        return found;
+    }
+
+
     private NBMetric oneMetricInTree(String pattern) {
         List<NBMetric> found = metricsInTree(pattern);
         if (found.size() != 1) {
@@ -132,4 +150,13 @@ public class NBFinders {
         return found.get(0);
     }
 
+    public <T extends NBMetric> T topMetric(String pattern, Class<T> type) {
+        List<T> metrics = this.metricsInTree(pattern, type);
+        if (!metrics.isEmpty()) {
+            return metrics.get(0);
+        } else {
+            throw new RuntimeException("top metric not found: pattern='" +pattern +"', type='" + type.getSimpleName() + "'");
+        }
+    }
+
 }

nb-api/src/main/java/io/nosqlbench/components/decorators/NBProviderSearch.java

@@ -14,12 +14,10 @@
  * limitations under the License.
  */
 
-package io.nosqlbench.engine.core.lifecycle.scenario.execution;
+package io.nosqlbench.components.decorators;
 
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.Optional;
 
-public class Extensions extends ConcurrentHashMap<String,String> {
+public interface NBProviderSearch {
-    public static Extensions ofNone() {
+    public <T> Optional<T> findParentService(Class<T> type);
-        return new Extensions();
-    }
 }

nb-api/src/main/java/io/nosqlbench/components/decorators/NBTokenWords.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023 nosqlbench
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.nosqlbench.components.decorators;
+
+import java.util.Map;
+
+public interface NBTokenWords {
+    Map<String,String> getTokens();
+}

nb-api/src/main/java/io/nosqlbench/engine/api/scripting/DiagReader.java

@@ -27,7 +27,7 @@ import java.util.List;
 public class DiagReader extends Reader {
     Reader wrapped;
     private final String prefix;
-    CharArrayWriter buffer = new CharArrayWriter(0);
+    final CharArrayWriter buffer;
     private final List<String> timedLog = new ArrayList<String>();
 
     private final DateTimeFormatter tsformat = DateTimeFormatter.ISO_DATE_TIME;
@@ -37,17 +37,23 @@ public class DiagReader extends Reader {
     public DiagReader(Reader wrapped, String prefix) {
         this.wrapped = wrapped;
         this.prefix = prefix;
+        this.buffer = new CharArrayWriter(0);
+    }
+
+    public DiagReader(Reader wrapped) {
+        this.wrapped = wrapped;
+        this.prefix = null;
+        this.buffer = null;
     }
 
     @Override
     public int read(char[] cbuf, int off, int len) throws IOException {
-        String tsprefix = LocalDateTime.now().format(tsformat);
-
         int read = wrapped.read(cbuf, off, len);
+        if (buffer!=null) {
+            String tsprefix = LocalDateTime.now().format(tsformat);
             buffer.write(cbuf, off, len);
-
             timedLog.add(tsprefix + prefix + new String(cbuf, off, len));
-
+        }
         return read;
     }
 

nb-api/src/main/java/io/nosqlbench/engine/api/scripting/DiagWriter.java

@@ -36,13 +36,20 @@ import java.util.regex.Pattern;
 public class DiagWriter extends PrintWriter {
 
     private final DateTimeFormatter tsformat = DateTimeFormatter.ISO_DATE_TIME;
-    Writer wrapped;
     InterjectingCharArrayWriter buffer;
 
-    public DiagWriter(Writer... writers) {
+    public DiagWriter(InterjectingCharArrayWriter charbuffer, Writer writer) {
-        super(new FanWriter(writers));
+        super(new FanWriter(charbuffer, writer));
-        this.wrapped = wrapped;
+        this.buffer = charbuffer;
-        this.buffer = buffer;
+    }
+
+    public DiagWriter(InterjectingCharArrayWriter charbuffer) {
+        super(charbuffer);
+        this.buffer = charbuffer;
+    }
+
+    public DiagWriter(PrintWriter out) {
+        super(out);
     }
 
     public String getBuf() {

nb-api/src/main/java/io/nosqlbench/engine/core/lifecycle/scenario/execution/BundledExtensions.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2023 nosqlbench
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.nosqlbench.engine.core.lifecycle.scenario.execution;
+
+import io.nosqlbench.api.extensions.ScriptingExtensionPluginInfo;
+import io.nosqlbench.components.NBComponent;
+import io.nosqlbench.nb.annotations.Service;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.Arrays;
+import java.util.Optional;
+import java.util.ServiceLoader;
+import java.util.stream.Stream;
+
+public class BundledExtensions {
+    private final static Logger logger = LogManager.getLogger(BundledExtensions.class);
+    private final NBComponent parent;
+
+    public BundledExtensions(NBComponent parent) {
+        this.parent = parent;
+    }
+
+    public static ScriptingExtensionPluginInfo<?>[] findAll() {
+        return ServiceLoader.load(ScriptingExtensionPluginInfo.class).stream()
+            .map(l -> l.get()).toArray(ScriptingExtensionPluginInfo[]::new);
+    }
+
+    public <T> Optional<T> load(String name, Class<T> type) {
+
+        ServiceLoader<ScriptingExtensionPluginInfo> loader = ServiceLoader.load(ScriptingExtensionPluginInfo.class);
+        return (Optional<T>) loader
+            .stream()
+            .filter(p -> {
+                return Arrays.stream(p.type().getAnnotationsByType(Service.class)).toList().get(0).selector().equals(name);
+            })
+            .map(p -> p.get().getExtensionObject(logger, parent))
+            .findAny()
+            .filter(raw -> type.isAssignableFrom(raw.getClass()))
+            .stream().findAny();
+    }
+}

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/DirectRuntimeScenarioTests.java

@@ -26,6 +26,7 @@ import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 
 import java.util.Map;
+import java.util.regex.Pattern;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -42,153 +43,164 @@ public class DirectRuntimeScenarioTests {
         ScenariosResults results = executor.awaitAllResults();
         System.out.println(results);
     }
-
-    @Disabled("enable before merge")
     @Test
-    public void testSC_activit_init_error() {
+    public void test_SC_linkedinput() {
-        SC_start_stop_diag scenario = new SC_start_stop_diag(testC, "SC_start_stop_diag");
+        NBScenario scenario = new SC_linkedinput(testC,"test_SC_linkedinput");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("SC_start_stop_diag"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        Pattern p = Pattern.compile(".*started leader.*started follower.*stopped leader.*stopped follower.*", Pattern.DOTALL);
+        assertThat(p.matcher(result.getIOLog()).matches()).isTrue();
+
+    }
+    @Test
+    public void testSC_activity_init_error() {
+        SC_activity_init_error scenario = new SC_activity_init_error(testC, "SC_activity_init_error");
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        assertThat(result.getException()).isNotNull();
+        assertThat(result.getException().getMessage()).contains("Unknown config parameter 'unknown_config'");
+        assertThat(result.getException()).isNotNull();
     }
 
+
     @Test
-    @Disabled("enable before merge")
     public void test_SC_activity_error() {
         NBScenario scenario = new SC_activity_error(testC,"test_SC_activity_error");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_activity_error"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        assertThat(result.getException()).isNotNull();
+        assertThat(result.getException().getMessage()).contains("For input string: \"unparsable\"");
+
     }
-    @Disabled("enable before merge")
-    @Test
-    public void test_SC_activity_init_error() {
-        NBScenario scenario = new SC_activity_init_error(testC,"test_SC_activity_init_error");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_activity_init_error"));
-    }
-    @Disabled("enable before merge")
     @Test
     public void test_SC_await_finished() {
         NBScenario scenario = new SC_await_finished(testC,"test_SC_await_finished");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_await_finished"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        assertThat(result.getIOLog()).contains("awaited activity");
     }
-    @Disabled("enable before merge")
     @Test
     public void test_SC_basicdiag() {
         NBScenario scenario = new SC_basicdiag(testC,"test_SC_basicdiag");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_basicdiag"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        assertThat(result.getIOLog().indexOf("starting activity basic_diag")).isGreaterThanOrEqualTo(0);
+        assertThat(result.getIOLog().indexOf("stopping activity basic_diag")).isGreaterThanOrEqualTo(1);
+        assertThat(result.getIOLog().indexOf("stopped activity basic_diag")).isGreaterThanOrEqualTo(2);
     }
-    @Disabled("enable before merge")
     @Test
     public void test_SC_blockingrun() {
         NBScenario scenario = new SC_blockingrun(testC,"test_SC_blockingrun");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_blockingrun"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+        assertThat(result.getIOLog()).matches(Pattern.compile(".*running.*finished.*running.*finished.*",Pattern.DOTALL));
     }
-    @Disabled("enable before merge")
+
+
+
     @Test
     public void test_SC_cocycledelay_bursty() {
         NBScenario scenario = new SC_cocycledelay_bursty(testC,"test_SC_cocycledelay_bursty");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_cocycledelay_bursty"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
         result.report();
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_cocycledelay_strict() {
         NBScenario scenario = new SC_cocycledelay_strict(testC,"test_SC_cocycledelay_strict");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_cocycledelay_strict"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_cycle_rate() {
         NBScenario scenario = new SC_cycle_rate(testC,"test_SC_cycle_rate");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_cycle_rate"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_cycle_rate_change() {
         NBScenario scenario = new SC_cycle_rate_change(testC,"test_SC_cycle_rate_change");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_cycle_rate_change"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_extension_csvmetrics() {
         NBScenario scenario = new SC_extension_csvmetrics(testC,"test_SC_extension_csvmetrics");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_extension_csvmetrics"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_extension_csvoutput() {
         NBScenario scenario = new SC_extension_csvoutput(testC,"test_SC_extension_csvoutput");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_extension_csvoutput"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_extension_histostatslogger() {
         NBScenario scenario = new SC_extension_histostatslogger(testC,"test_SC_extension_histostatslogger");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_extension_histostatslogger"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_extension_shutdown_hook() {
         NBScenario scenario = new SC_extension_shutdown_hook(testC,"test_SC_extension_shutdown_hook");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_extension_shutdown_hook"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+    }
+    @Test
+    public void test_SC_extension_example() {
+        NBScenario scenario = new SC_extension_example(testC,"test_SC_extension_example");
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
+//        result.exitWithCode();
+        assertThat(result.getIOLog()).contains("3+5=8");
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_histologger() {
         NBScenario scenario = new SC_histologger(testC,"test_SC_histologger");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_histologger"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
-    }
-    @Disabled("enable before merge")
-    @Test
-    public void test_SC_linkedinput() {
-        NBScenario scenario = new SC_linkedinput(testC,"test_SC_linkedinput");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_linkedinput"));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_optimo() {
         NBScenario scenario = new SC_optimo_test(testC,"test_SC_optimo");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_optimo"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
         System.out.println(result);
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_params_variable() {
         NBScenario scenario = new SC_params_variable(testC,"test_SC_params_variable");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_params_variable"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_readmetrics() {
         NBScenario scenario = new SC_readmetrics(testC,"test_SC_readmetrics");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_readmetrics"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_speedcheck() {
         NBScenario scenario = new SC_speedcheck(testC,"test_SC_speedcheck");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_speedcheck"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_start_stop_diag() {
         NBScenario scenario = new SC_start_stop_diag(testC,"test_SC_start_stop_diag");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_start_stop_diag"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_threadchange() {
         NBScenario scenario = new SC_threadchange(testC,"test_SC_threadchange");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_threadchange"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_threadspeeds() {
         NBScenario scenario = new SC_threadspeeds(testC,"test_SC_threadspeeds");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_threadspeeds"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
     }
     @Disabled("enable before merge")
     @Test
     public void test_SC_undef_param() {
         NBScenario scenario = new SC_undef_param(testC, "test_SC_undef_param");
-        ScenarioResult result = scenario.apply(NBSceneBuffer.init("test_SC_undef_param"));
+        ScenarioResult result = scenario.apply(NBSceneBuffer.traced(scenario));
         String out = result.getIOLog();
         assertThat(out).contains("foobar");
     }

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/SC_basicdiag.java

@@ -44,5 +44,8 @@ public class SC_basicdiag extends SCBaseScenario {
         );
         stdout.println("starting activity basic_diag");
         controller.start(basic_diag);
+        stdout.println("stopping activity basic_diag");
+        controller.stop(basic_diag);
+        stdout.println("stopped activity basic_diag");
     }
 }

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/SC_blockingrun.java

@@ -57,13 +57,13 @@ public class SC_blockingrun extends SCBaseScenario {
     public void invoke() {
         var activitydef1 = Map.of(
             "alias","blockactivity1","driver","diag",
-            "cycles","0..100000","threads","1",
+            "cycles","0..10000","threads","1",
             "interval","2000","op","noop"
         );
 
         var activitydef2 = Map.of(
             "alias", "blockingactivity2","driver","diag",
-            "cycles","0..100000","threads","1",
+            "cycles","0..10000","threads","1",
             "interval","2000", "op","noop"
         );
 

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/SC_cocycledelay_bursty.java

@@ -18,7 +18,11 @@ package io.nosqlbench.nbr.examples.injava;
 
 import io.nosqlbench.api.engine.metrics.instruments.NBMetricCounter;
 import io.nosqlbench.api.engine.metrics.instruments.NBMetricGauge;
+import io.nosqlbench.api.engine.metrics.instruments.NBMetricTimer;
 import io.nosqlbench.components.NBComponent;
+import io.nosqlbench.components.events.ParamChange;
+import io.nosqlbench.engine.api.activityapi.core.Activity;
+import io.nosqlbench.engine.api.activityapi.ratelimits.simrate.CycleRateSpec;
 import io.nosqlbench.engine.core.lifecycle.scenario.direct.SCBaseScenario;
 
 import java.util.Map;
@@ -81,68 +85,60 @@ public class SC_cocycledelay_bursty extends SCBaseScenario {
      */
     @Override
     public void invoke() {
+        int diagrate = 500;
         var co_cycle_delay_bursty = Map.of(
             "alias", "co_cycle_delay_bursty",
             "driver", "diag",
             "cycles", "0..1000000",
             "threads", "1",
-            "cyclerate", "10,1.5",
+            "cyclerate", "1000,1.5",
-            "op", "log: level=info"
+            "op", "diagrate: diagrate=" + diagrate
+//            "dryrun", "op" // silent
         );
 
-        controller.waitMillis(1000);
+        controller.waitMillis(500);
         stdout.println("starting activity co_cycle_delay_bursty");
-        controller.start(co_cycle_delay_bursty);
+        Activity activity = controller.start(co_cycle_delay_bursty);
+        controller.waitMillis(1000);
+
+        NBMetricTimer service_time_counter = find().topMetric("activity=co_cycle_delay_bursty,name=cycles_servicetime", NBMetricTimer.class);
+        NBMetricGauge wait_time_gauge = find().topMetric("activity=co_cycle_delay_bursty,name=cycles_waittime",NBMetricGauge.class);
+
+        for (int i = 0; i < 5; i++) {
+            controller.waitMillis(1000);
+            if (!controller.isRunningActivity("co_cycle_delay_bursty")) {
+                throw new RuntimeException("Scenario exited prematurely.");
+            }
+
+            stdout.println("backlogging, cycles=" + service_time_counter.getCount() +
+                " waittime=" + wait_time_gauge.getValue() +
+                " diagrate=" + diagrate +
+                " cyclerate=" + activity.getCycleLimiter().getSpec()
+            );
+        }
+
+        stdout.println("step1 waittime=" + wait_time_gauge.getValue());
+        onEvent(new ParamChange<>(new CycleRateSpec(10000, 1.1)));
+
+        for (int i = 0; i < 10; i++) {
+            if (!controller.isRunningActivity("co_cycle_delay_bursty")) {
+                throw new RuntimeException("scenario exited prematurely.");
+            }
+            stdout.println("backlogging, cycles=" + service_time_counter.getCount() +
+                " waittime=" + wait_time_gauge.getValue() +
+                " diagrate=" + diagrate +
+                " cyclerate=" + activity.getCycleLimiter().getSpec()
+            );
+            if (wait_time_gauge.getValue() < 50000000) {
+                stdout.println("waittime trended back down as expected, exiting on iteration " + i);
+                break;
+            }
+        }
+
+        stdout.println("step2 metrics.waittime=" + wait_time_gauge.getValue());
+        controller.stop(co_cycle_delay_bursty);
+
+        stdout.println("stopped activity co_cycle_delay_bursty");
 
-        NBMetricCounter service_time_counter = find().counter("activity=co_cycle_delay_bursty,name=cycles_servicetime");
-        NBMetricGauge wait_time_gauge = find().gauge("activity=co_cycle_delay_bursty,name=cycles_waittime");
-        String diagrate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("diagrate").toString();
-        String cyclerate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("cyclerate").toString();
-//
-//        for (int i = 0; i < 5; i++) {
-//            controller.waitMillis(1000);
-//            if (!controller.isRunningActivity(co_cycle_delay_bursty)) {
-//                stdout.println("scenario exited prematurely, aborting.");
-//                break;
-//            }
-//            diagrate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("diagrate").toString();
-//            cyclerate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("cyclerate").toString();
-//            stdout.println(
-//                "backlogging, cycles=" + service_time_counter.getCount() +
-//                " waittime=" + wait_time_gauge.getValue() +
-//                " diagrate=" + diagrate +
-//                " cyclerate=" + cyclerate
-//            );
-//        }
-//
-//        stdout.println("step1 metrics.waittime=" + wait_time_gauge.getValue());
-//        controller.getActivityDef("co_cycle_delay_bursty").getParams().put("diagrate", "10000");
-//
-//        for (int i = 0; i < 10; i++) {
-//            if (!controller.isRunningActivity("co_cycle_delay_bursty")) {
-//                stdout.println("scenario exited prematurely, aborting.");
-//                break;
-//            }
-//            diagrate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("diagrate").toString();
-//            cyclerate = controller.getActivityDef("co_cycle_delay_bursty").getParams().get("cyclerate").toString();
-//
-//            stdout.println(
-//                "recovering, cycles=" + service_time_counter.getCount() +
-//                " waittime=" + wait_time_gauge.getValue() +
-//                    " diagrate=" + diagrate +
-//                    " cyclerate=" + cyclerate
-//            );
-//
-//            controller.waitMillis(1000);
-//            if (wait_time_gauge.getValue() < 50000000) {
-//                stdout.println("waittime trended back down as expected, exiting on iteration " + i);
-//                break;
-//            }
-//        }
-//
-//        stdout.println("step2 metrics.waittime=" + wait_time_gauge.getValue());
-//        controller.stop(co_cycle_delay_bursty);
-//
-//        stdout.println("stopped activity co_cycle_delay_bursty");
     }
 }

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/SC_extension_example.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2023 nosqlbench
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.nosqlbench.nbr.examples.injava;
+
+import io.nosqlbench.components.NBComponent;
+import io.nosqlbench.engine.core.lifecycle.scenario.direct.SCBaseScenario;
+import io.nosqlbench.engine.extensions.example.ExamplePlugin;
+
+public class SC_extension_example extends SCBaseScenario {
+    public SC_extension_example(NBComponent parentComponent, String scenarioName) {
+        super(parentComponent, scenarioName);
+    }
+
+    /** <pre>{@code
+     * var csvlogger = csvoutput.open("logs/csvoutputtestfile.csv","header1","header2");
+     *
+     * csvlogger.write({"header1": "value1","header2":"value2"});
+     * }</pre>
+     */
+    @Override
+    public void invoke() {
+        ExamplePlugin examplePlugin = create().requiredExtension("example", ExamplePlugin.class);
+        long sum = examplePlugin.getSum(3, 5);
+        stdout.println("3+5=" + sum);
+    }
+}

nbr-examples/src/test/java/io/nosqlbench/nbr/examples/injava/SC_linkedinput.java

@@ -19,12 +19,15 @@ package io.nosqlbench.nbr.examples.injava;
 import io.nosqlbench.components.NBComponent;
 import io.nosqlbench.engine.core.lifecycle.scenario.direct.SCBaseScenario;
 
+import java.util.Map;
+
 public class SC_linkedinput extends SCBaseScenario {
     public SC_linkedinput(NBComponent parentComponent, String scenarioName) {
         super(parentComponent, scenarioName);
     }
 
-    /** <pre>{@code
+    /**
+     * <pre>{@code
      * var leader = {
      *     driver: 'diag',
      *     alias: 'leader',
@@ -55,5 +58,30 @@ public class SC_linkedinput extends SCBaseScenario {
     @Override
     public void invoke() {
 
+        var leader = Map.of(
+            "driver", "diag",
+            "alias", "leader",
+            "targetrate", "10000",
+            "op", "log:level=info"
+        );
+
+        var follower = Map.of(
+            "driver", "diag",
+            "alias", "follower",
+            "op", "log:level=INFO"
+
+        );
+
+        controller.start(leader);
+        stdout.println("started leader");
+        controller.start(follower);
+        stdout.println("started follower");
+
+        controller.waitMillis(500);
+        controller.stop(leader);
+        stdout.println("stopped leader");
+        controller.stop(follower);
+        stdout.println("stopped follower");
+
     }
 }

nbr/src/main/java/io/nosqlbench/scenarios/PerfWindowSampler.java

@@ -55,7 +55,7 @@ public class PerfWindowSampler {
     }
 
     double getValue() {
-        if (windows.size()==0) {
+        if (windows.size() == 0) {
             return Double.NaN;
         }
         return windows.getLast().value();
@@ -64,15 +64,16 @@ public class PerfWindowSampler {
     @Override
     public String toString() {
         StringBuilder sb = new StringBuilder("PERF VALUE=").append(getValue()).append("\n");
-        sb.append("windows:\n"+windows.getLast().toString());
+        sb.append("windows:\n" + windows.getLast().toString());
         return sb.toString();
     }
 
     public void startWindow() {
         startWindow(System.currentTimeMillis());
     }
+
     public void startWindow(long now) {
-        if (window!=null) {
+        if (window != null) {
             throw new RuntimeException("cant start window twice in a row. Must close window first");
         }
         List<ParamSample> samples = criteria.stream().map(c -> ParamSample.init(c).start(now)).toList();
@@ -82,12 +83,13 @@ public class PerfWindowSampler {
     public void stopWindow() {
         stopWindow(System.currentTimeMillis());
     }
+
     public void stopWindow(long now) {
         for (int i = 0; i < window.size(); i++) {
-            window.set(i,window.get(i).stop(now));
+            window.set(i, window.get(i).stop(now));
         }
         windows.add(window);
-        window=null;
+        window = null;
     }
 
     public static record Criterion(
@@ -96,18 +98,27 @@ public class PerfWindowSampler {
         double weight,
         Runnable callback,
         boolean delta
-    ) { }
+    ) {
+    }
+
+    public static class WindowSamples extends ArrayList<WindowSample> {
+    }
 
-    public static class WindowSamples extends ArrayList<WindowSample> {}
     public static class WindowSample extends ArrayList<ParamSample> {
         public WindowSample(List<ParamSample> samples) {
             super(samples);
         }
 
         public double value() {
-            return stream().mapToDouble(ParamSample::weightedValue).sum();
+            double product = 1.0;
+            for (ParamSample sample : this) {
+                product *= sample.weightedValue();
+            }
+
+            return product;
         }
     }
+
     public static record ParamSample(Criterion criterion, long startAt, long endAt, double startval, double endval) {
         public double weightedValue() {
             return rawValue() * criterion().weight;
@@ -121,24 +132,26 @@ public class PerfWindowSampler {
         }
 
         private double rate() {
-            return rawValue()/seconds();
+            return rawValue() / seconds();
         }
+
         private double seconds() {
-            return ((double)(endAt-startAt)) / 1000d;
+            return ((double) (endAt - startAt)) / 1000d;
         }
 
         public static ParamSample init(Criterion criterion) {
-            return new ParamSample(criterion, 0,0,Double.NaN, Double.NaN);
+            return new ParamSample(criterion, 0, 0, Double.NaN, Double.NaN);
         }
 
         public ParamSample start(long startTime) {
             criterion.callback.run();
             double v1 = criterion.supplier.getAsDouble();
-            return new ParamSample(criterion,startTime,0L, v1, Double.NaN);
+            return new ParamSample(criterion, startTime, 0L, v1, Double.NaN);
         }
+
         public ParamSample stop(long stopTime) {
             double v2 = criterion.supplier.getAsDouble();
-            return new ParamSample(criterion,startAt,stopTime,startval, v2);
+            return new ParamSample(criterion, startAt, stopTime, startval, v2);
         }
 
         @Override

nbr/src/test/java/io/nosqlbench/scenarios/PerfWindowSamplerTest.java

@@ -60,8 +60,8 @@ class PerfWindowSamplerTest {
         assertThat(value).isCloseTo(30.0,Offset.offset(0.001));
 
         pws.startWindow(10000L);
-        a1.set(42); // 42-10=32
+        a1.set(42); // 42-3=39
-        a2.set(42); // 42-1=41; 41+32=73
+        a2.set(42); // 42-10=32
 
         pws.stopWindow(11000L);
         double value2 = pws.getValue();