fix #117: add a log level setting

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+* Add a log level setting ([#117](https://github.com/evanw/esbuild/issues/117))
+
+    You can now silence esbuild except for errors with `--log-level=error`, or except for errors and warnings with `--log-level=warning`.
+
 ## 0.4.0
 
 * Add the `esm` output format ([#48](https://github.com/evanw/esbuild/issues/48))

README.md

@@ -240,6 +240,7 @@ Advanced options:
   --sourcemap=external  Do not link to the source map with a comment
   --sourcefile=...      Set the source file for the source map (for stdin)
   --error-limit=...     Maximum error count or 0 to disable (default 10)
+  --log-level=...       Disable logging (info, warning, error)
 
   --trace=...           Write a CPU trace to this file
   --cpuprofile=...      Write a CPU profile to this file

cmd/esbuild/main.go

@@ -54,6 +54,7 @@ Advanced options:
   --sourcemap=external  Do not link to the source map with a comment
   --sourcefile=...      Set the source file for the source map (for stdin)
   --error-limit=...     Maximum error count or 0 to disable (default 10)
+  --log-level=...       Disable logging (info, warning, error)
 
   --trace=...           Write a CPU trace to this file
   --cpuprofile=...      Write a CPU profile to this file
@@ -84,6 +85,12 @@ type argsObject struct {
 	entryPaths     []string
 }
 
+func (args argsObject) logInfo(text string) {
+	if args.logOptions.LogLevel <= logging.LevelInfo {
+		fmt.Fprintf(os.Stderr, "%s\n", text)
+	}
+}
+
 func exitWithError(text string) {
 	colorRed := ""
 	colorBold := ""
@@ -377,6 +384,18 @@ func parseArgs(fs fs.FS, rawArgs []string) (argsObject, error) {
 				return argsObject{}, fmt.Errorf("Invalid JSX fragment: %s", arg)
 			}
 
+		case strings.HasPrefix(arg, "--log-level="):
+			switch arg[len("--log-level="):] {
+			case "info":
+				args.logOptions.LogLevel = logging.LevelInfo
+			case "warning":
+				args.logOptions.LogLevel = logging.LevelWarning
+			case "error":
+				args.logOptions.LogLevel = logging.LevelError
+			default:
+				return argsObject{}, fmt.Errorf("Invalid log level: %s", arg)
+			}
+
 		case strings.HasPrefix(arg, "--trace="):
 			args.traceFile = arg[len("--trace="):]
 
@@ -438,9 +457,6 @@ func parseArgs(fs fs.FS, rawArgs []string) (argsObject, error) {
 		// Write to stdout by default if there's only one input file
 		if len(args.entryPaths) == 1 && args.bundleOptions.AbsOutputFile == "" && args.bundleOptions.AbsOutputDir == "" {
 			args.bundleOptions.WriteToStdout = true
-			if args.bundleOptions.SourceMap != bundler.SourceMapNone {
-				args.bundleOptions.SourceMap = bundler.SourceMapInline
-			}
 		}
 	} else if !logging.GetTerminalInfo(os.Stdin).IsTTY {
 		// If called with no input files and we're not a TTY, read from stdin instead
@@ -457,9 +473,16 @@ func parseArgs(fs fs.FS, rawArgs []string) (argsObject, error) {
 				return argsObject{}, fmt.Errorf("Cannot use --outdir when reading from stdin")
 			}
 			args.bundleOptions.WriteToStdout = true
-			if args.bundleOptions.SourceMap != bundler.SourceMapNone {
-				args.bundleOptions.SourceMap = bundler.SourceMapInline
-			}
+		}
+	}
+
+	// Change the default value for some settings if we're writing to stdout
+	if args.bundleOptions.WriteToStdout {
+		if args.bundleOptions.SourceMap != bundler.SourceMapNone {
+			args.bundleOptions.SourceMap = bundler.SourceMapInline
+		}
+		if args.logOptions.LogLevel == logging.LevelNone {
+			args.logOptions.LogLevel = logging.LevelWarning
 		}
 	}
 
@@ -520,7 +543,7 @@ func main() {
 			}
 			defer func() {
 				f.Close()
-				fmt.Fprintf(os.Stderr, "Wrote to %s\n", args.traceFile)
+				args.logInfo(fmt.Sprintf("Wrote to %s", args.traceFile))
 			}()
 			trace.Start(f)
 			defer trace.Stop()
@@ -537,7 +560,7 @@ func main() {
 			}
 			defer func() {
 				f.Close()
-				fmt.Fprintf(os.Stderr, "Wrote to %s\n", args.cpuprofileFile)
+				args.logInfo(fmt.Sprintf("Wrote to %s", args.cpuprofileFile))
 			}()
 			pprof.StartCPUProfile(f)
 			defer pprof.StopCPUProfile()
@@ -548,7 +571,7 @@ func main() {
 			// return useful information for esbuild, since it's so fast. Let's keep
 			// running for 30 seconds straight, which should give us 3,000 samples.
 			seconds := 30.0
-			fmt.Fprintf(os.Stderr, "Running for %g seconds straight due to --cpuprofile...\n", seconds)
+			args.logInfo(fmt.Sprintf("Running for %g seconds straight due to --cpuprofile...", seconds))
 			for time.Since(start).Seconds() < seconds {
 				run(fs, args)
 			}
@@ -563,9 +586,7 @@ func main() {
 		}
 	}()
 
-	if !args.bundleOptions.WriteToStdout {
-		fmt.Fprintf(os.Stderr, "Done in %dms\n", time.Since(start).Nanoseconds()/1000000)
-	}
+	args.logInfo(fmt.Sprintf("Done in %dms", time.Since(start).Nanoseconds()/1000000))
 }
 
 func run(fs fs.FS, args argsObject) {
@@ -612,9 +633,7 @@ func run(fs fs.FS, args argsObject) {
 		if err != nil {
 			exitWithError(fmt.Sprintf("Failed to write to %s (%s)", path, err.Error()))
 		}
-		if !args.bundleOptions.WriteToStdout {
-			fmt.Fprintf(os.Stderr, "Wrote to %s (%s)\n", path, toSize(len(item.JsContents)))
-		}
+		args.logInfo(fmt.Sprintf("Wrote to %s (%s)", path, toSize(len(item.JsContents))))
 
 		// Also write the source map
 		if item.SourceMapAbsPath != "" {
@@ -623,9 +642,7 @@ func run(fs fs.FS, args argsObject) {
 			if err != nil {
 				exitWithError(fmt.Sprintf("Failed to write to %s: (%s)", path, err.Error()))
 			}
-			if !args.bundleOptions.WriteToStdout {
-				fmt.Fprintf(os.Stderr, "Wrote to %s (%s)\n", path, toSize(len(item.SourceMapContents)))
-			}
+			args.logInfo(fmt.Sprintf("Wrote to %s (%s)", path, toSize(len(item.SourceMapContents))))
 		}
 	}
 }

internal/logging/logging.go

@@ -17,7 +17,16 @@ type Log struct {
 	msgs chan Msg
 }
 
-type MsgKind int
+type LogLevel int8
+
+const (
+	LevelNone LogLevel = iota
+	LevelInfo
+	LevelWarning
+	LevelError
+)
+
+type MsgKind uint8
 
 const (
 	Error MsgKind = iota
@@ -66,10 +75,6 @@ func (s *Source) RangeOfString(loc ast.Loc) ast.Range {
 	return ast.Range{loc, 0}
 }
 
-func NewLog(msgs chan Msg) Log {
-	return Log{msgs}
-}
-
 type MsgCounts struct {
 	Errors   int
 	Warnings int
@@ -109,7 +114,7 @@ type TerminalInfo struct {
 func NewStderrLog(options StderrOptions) (Log, func() MsgCounts) {
 	msgs := make(chan Msg)
 	done := make(chan MsgCounts)
-	log := NewLog(msgs)
+	log := Log{msgs}
 	terminalInfo := GetTerminalInfo(os.Stderr)
 
 	switch options.Color {
@@ -122,15 +127,22 @@ func NewStderrLog(options StderrOptions) (Log, func() MsgCounts) {
 	go func(msgs chan Msg, done chan MsgCounts) {
 		counts := MsgCounts{}
 		for msg := range msgs {
-			os.Stderr.WriteString(msg.String(options, terminalInfo))
 			switch msg.Kind {
 			case Error:
 				counts.Errors++
+				if options.LogLevel <= LevelError {
+					os.Stderr.WriteString(msg.String(options, terminalInfo))
+				}
 			case Warning:
 				counts.Warnings++
+				if options.LogLevel <= LevelWarning {
+					os.Stderr.WriteString(msg.String(options, terminalInfo))
+				}
 			}
 			if options.ExitWhenLimitIsHit && options.ErrorLimit != 0 && counts.Errors >= options.ErrorLimit {
-				fmt.Fprintf(os.Stderr, "%s reached (disable error limit with --error-limit=0)\n", counts.String())
+				if options.LogLevel <= LevelInfo {
+					fmt.Fprintf(os.Stderr, "%s reached (disable error limit with --error-limit=0)\n", counts.String())
+				}
 				os.Exit(1)
 			}
 		}
@@ -140,7 +152,7 @@ func NewStderrLog(options StderrOptions) (Log, func() MsgCounts) {
 	return log, func() MsgCounts {
 		close(log.msgs)
 		counts := <-done
-		if counts.Warnings != 0 || counts.Errors != 0 {
+		if options.LogLevel <= LevelInfo && (counts.Warnings != 0 || counts.Errors != 0) {
 			fmt.Fprintf(os.Stderr, "%s\n", counts.String())
 		}
 		return counts
@@ -150,7 +162,7 @@ func NewStderrLog(options StderrOptions) (Log, func() MsgCounts) {
 func NewDeferLog() (Log, func() []Msg) {
 	msgs := make(chan Msg)
 	done := make(chan []Msg)
-	log := NewLog(msgs)
+	log := Log{msgs}
 
 	go func(msgs chan Msg, done chan []Msg) {
 		result := []Msg{}
@@ -186,6 +198,7 @@ type StderrOptions struct {
 	ErrorLimit         int
 	ExitWhenLimitIsHit bool
 	Color              StderrColor
+	LogLevel           LogLevel
 }
 
 func (msg Msg) String(options StderrOptions, terminalInfo TerminalInfo) string {

npm/esbuild/lib/main.d.ts

@@ -2,6 +2,7 @@ export declare type Target = 'esnext' | 'es6' | 'es2015' | 'es2016' | 'es2017' |
 export declare type Platform = 'browser' | 'node';
 export declare type Format = 'iife' | 'cjs' | 'esm';
 export declare type Loader = 'js' | 'jsx' | 'ts' | 'tsx' | 'json' | 'text' | 'base64' | 'dataurl';
+export declare type LogLevel = 'info' | 'warning' | 'error';
 
 interface CommonOptions {
   sourcemap?: boolean | 'inline' | 'external';
@@ -29,6 +30,7 @@ export interface BuildOptions extends CommonOptions {
   color?: boolean;
   external?: string[];
   loader?: { [ext: string]: Loader };
+  logLevel?: LogLevel;
 
   entryPoints: string[];
 

npm/esbuild/lib/main.js

@@ -86,6 +86,7 @@ exports.build = options => {
     if (options.platform) flags.push(`--platform=${options.platform}`);
     if (options.format) flags.push(`--format=${options.format}`);
     if (options.color) flags.push(`--color=${options.color}`);
+    if (options.logLevel) flags.push(`--log-level=${options.logLevel}`);
     if (options.external) for (const name of options.external) flags.push(`--external:${name}`);
     if (options.loader) for (const ext in options.loader) flags.push(`--loader:${ext}=${options.loader[ext]}`);