Allow log level to be specified in an env var (#3721)

command/server.go

@@ -74,14 +74,14 @@ type ServerCommand struct {
 func (c *ServerCommand) Run(args []string) int {
 	var dev, verifyOnly, devHA, devTransactional, devLeasedKV, devThreeNode, devSkipInit bool
 	var configPath []string
-	var logLevel, devRootTokenID, devListenAddress, devPluginDir string
+	var logLevelFlag, devRootTokenID, devListenAddress, devPluginDir string
 	var devLatency, devLatencyJitter int
 	flags := c.Meta.FlagSet("server", meta.FlagSetDefault)
 	flags.BoolVar(&dev, "dev", false, "")
 	flags.StringVar(&devRootTokenID, "dev-root-token-id", "", "")
 	flags.StringVar(&devListenAddress, "dev-listen-address", "", "")
 	flags.StringVar(&devPluginDir, "dev-plugin-dir", "", "")
-	flags.StringVar(&logLevel, "log-level", "info", "")
+	flags.StringVar(&logLevelFlag, "log-level", "", "")
 	flags.IntVar(&devLatency, "dev-latency", 0, "")
 	flags.IntVar(&devLatencyJitter, "dev-latency-jitter", 20, "")
 	flags.BoolVar(&verifyOnly, "verify-only", false, "")
@@ -100,19 +100,25 @@ func (c *ServerCommand) Run(args []string) int {
 	// start logging too early.
 	c.logGate = &gatedwriter.Writer{Writer: colorable.NewColorable(os.Stderr)}
 	var level int
-	logLevel = strings.ToLower(strings.TrimSpace(logLevel))
+	var logLevel string
+	if os.Getenv("VAULT_LOG_LEVEL") != "" {
+		logLevel = os.Getenv("VAULT_LOG_LEVEL")
+	}
+	if logLevelFlag != "" {
+		logLevel = strings.ToLower(strings.TrimSpace(logLevelFlag))
+	}
 	switch logLevel {
 	case "trace":
 		level = log.LevelTrace
 	case "debug":
 		level = log.LevelDebug
-	case "info":
+	case "info", "":
 		level = log.LevelInfo
 	case "notice":
 		level = log.LevelNotice
-	case "warn":
+	case "warn", "warning":
 		level = log.LevelWarn
-	case "err":
+	case "err", "error":
 		level = log.LevelError
 	default:
 		c.Ui.Output(fmt.Sprintf("Unknown log level %s", logLevel))
@@ -1278,7 +1284,8 @@ General Options:
 
   -log-level=info         Log verbosity. Defaults to "info", will be output to
                           stderr. Supported values: "trace", "debug", "info",
-                          "warn", "err"
+                          "warn", "err". Can also be specified with  the
+                          VAULT_LOG_LEVEL environment variable.
 `
 	return strings.TrimSpace(helpText)
 }