Merge #3380: Filter logs by log level in TF_LOG

config_unix.go

@@ -33,7 +33,7 @@ func configDir() (string, error) {
 func homeDir() (string, error) {
 	// First prefer the HOME environmental variable
 	if home := os.Getenv("HOME"); home != "" {
-		log.Printf("Detected home directory from env var: %s", home)
+		log.Printf("[DEBUG] Detected home directory from env var: %s", home)
 		return home, nil
 	}
 

log.go

@@ -2,28 +2,65 @@ package main
 
 import (
 	"io"
+	"log"
 	"os"
+	"strings"
+
+	"github.com/hashicorp/logutils"
 )
 
 // These are the environmental variables that determine if we log, and if
 // we log whether or not the log should go to a file.
-const EnvLog = "TF_LOG"          //Set to True
-const EnvLogFile = "TF_LOG_PATH" //Set to a file
+const (
+	EnvLog     = "TF_LOG"      // Set to True
+	EnvLogFile = "TF_LOG_PATH" // Set to a file
+)
 
-// logOutput determines where we should send logs (if anywhere).
+var validLevels = []logutils.LogLevel{"TRACE", "DEBUG", "INFO", "WARN", "ERROR"}
+
+// logOutput determines where we should send logs (if anywhere) and the log level.
 func logOutput() (logOutput io.Writer, err error) {
 	logOutput = nil
-	if os.Getenv(EnvLog) != "" {
-		logOutput = os.Stderr
+	envLevel := os.Getenv(EnvLog)
+	if envLevel == "" {
+		return
+	}
 
-		if logPath := os.Getenv(EnvLogFile); logPath != "" {
-			var err error
-			logOutput, err = os.Create(logPath)
-			if err != nil {
-				return nil, err
-			}
+	logOutput = os.Stderr
+	if logPath := os.Getenv(EnvLogFile); logPath != "" {
+		var err error
+		logOutput, err = os.Create(logPath)
+		if err != nil {
+			return nil, err
 		}
 	}
 
+	// This was the default since the beginning
+	logLevel := logutils.LogLevel("TRACE")
+
+	if isValidLogLevel(envLevel) {
+		// allow following for better ux: info, Info or INFO
+		logLevel = logutils.LogLevel(strings.ToUpper(envLevel))
+	} else {
+		log.Printf("[WARN] Invalid log level: %q. Defaulting to level: TRACE. Valid levels are: %+v",
+			envLevel, validLevels)
+	}
+
+	logOutput = &logutils.LevelFilter{
+		Levels:   validLevels,
+		MinLevel: logLevel,
+		Writer:   logOutput,
+	}
+
 	return
 }
+
+func isValidLogLevel(level string) bool {
+	for _, l := range validLevels {
+		if strings.ToUpper(level) == string(l) {
+			return true
+		}
+	}
+
+	return false
+}

plugin/client.go

@@ -88,7 +88,7 @@ func CleanupClients() {
 		}(client)
 	}
 
-	log.Println("waiting for all plugin processes to complete...")
+	log.Println("[DEBUG] waiting for all plugin processes to complete...")
 	wg.Wait()
 }
 
@@ -326,7 +326,7 @@ func (c *Client) logStderr(r io.Reader) {
 			c.config.Stderr.Write([]byte(line))
 
 			line = strings.TrimRightFunc(line, unicode.IsSpace)
-			log.Printf("%s: %s", filepath.Base(c.config.Cmd.Path), line)
+			log.Printf("[DEBUG] %s: %s", filepath.Base(c.config.Cmd.Path), line)
 		}
 
 		if err == io.EOF {

terraform/context.go

@@ -513,7 +513,7 @@ func (c *Context) releaseRun(ch chan<- struct{}) {
 func (c *Context) walk(
 	graph *Graph, operation walkOperation) (*ContextGraphWalker, error) {
 	// Walk the graph
-	log.Printf("[INFO] Starting graph walk: %s", operation.String())
+	log.Printf("[DEBUG] Starting graph walk: %s", operation.String())
 	walker := &ContextGraphWalker{Context: c, Operation: operation}
 	return walker, graph.Walk(walker)
 }

terraform/eval_validate.go

@@ -49,9 +49,12 @@ func (n *EvalValidateCount) Eval(ctx EvalContext) (interface{}, error) {
 	}
 
 RETURN:
-	return nil, &EvalValidateError{
-		Errors: errs,
+	if len(errs) != 0 {
+		err = &EvalValidateError{
+			Errors: errs,
+		}
 	}
+	return nil, err
 }
 
 // EvalValidateProvider is an EvalNode implementation that validates