Extract query hints

public/app/plugins/datasource/prometheus/query_hints.ts

@@ -0,0 +1,99 @@
+import _ from 'lodash';
+
+export function getQueryHints(series: any[], datasource?: any): any[] {
+  const hints = series.map((s, i) => {
+    const query: string = s.query;
+    const index: number = s.responseIndex;
+    if (query === undefined || index === undefined) {
+      return null;
+    }
+
+    // ..._bucket metric needs a histogram_quantile()
+    const histogramMetric = query.trim().match(/^\w+_bucket$/);
+    if (histogramMetric) {
+      const label = 'Time series has buckets, you probably wanted a histogram.';
+      return {
+        index,
+        label,
+        fix: {
+          label: 'Fix by adding histogram_quantile().',
+          action: {
+            type: 'ADD_HISTOGRAM_QUANTILE',
+            query,
+            index,
+          },
+        },
+      };
+    }
+
+    // Check for monotony
+    const datapoints: number[][] = s.datapoints;
+    if (query.indexOf('rate(') === -1 && datapoints.length > 1) {
+      let increasing = false;
+      const monotonic = datapoints.filter(dp => dp[0] !== null).every((dp, index) => {
+        if (index === 0) {
+          return true;
+        }
+        increasing = increasing || dp[0] > datapoints[index - 1][0];
+        // monotonic?
+        return dp[0] >= datapoints[index - 1][0];
+      });
+      if (increasing && monotonic) {
+        const simpleMetric = query.trim().match(/^\w+$/);
+        let label = 'Time series is monotonously increasing.';
+        let fix;
+        if (simpleMetric) {
+          fix = {
+            label: 'Fix by adding rate().',
+            action: {
+              type: 'ADD_RATE',
+              query,
+              index,
+            },
+          };
+        } else {
+          label = `${label} Try applying a rate() function.`;
+        }
+        return {
+          label,
+          index,
+          fix,
+        };
+      }
+    }
+
+    // Check for recording rules expansion
+    if (datasource && datasource.ruleMappings) {
+      const mapping = datasource.ruleMappings;
+      const mappingForQuery = Object.keys(mapping).reduce((acc, ruleName) => {
+        if (query.search(ruleName) > -1) {
+          return {
+            ...acc,
+            [ruleName]: mapping[ruleName],
+          };
+        }
+        return acc;
+      }, {});
+      if (_.size(mappingForQuery) > 0) {
+        const label = 'Query contains recording rules.';
+        return {
+          label,
+          index,
+          fix: {
+            label: 'Expand rules',
+            action: {
+              type: 'EXPAND_RULES',
+              query,
+              index,
+              mapping: mappingForQuery,
+            },
+          },
+        };
+      }
+    }
+
+    // No hint found
+    return null;
+  });
+  return hints;
+}