disable user function logs at debug level config (#1179)

api/agent/agent_test.go

@@ -342,7 +342,7 @@ func TestLoggerIsStringerAndWorks(t *testing.T) {
 	// TODO test limit writer, logrus writer, etc etc
 
 	var call models.Call
-	logger := setupLogger(context.Background(), 1*1024*1024, &call)
+	logger := setupLogger(context.Background(), 1*1024*1024, true, &call)
 
 	if _, ok := logger.(fmt.Stringer); !ok {
 		// NOTE: if you are reading, maybe what you've done is ok, but be aware we were relying on this for optimization...
@@ -366,7 +366,7 @@ func TestLoggerIsStringerAndWorks(t *testing.T) {
 func TestLoggerTooBig(t *testing.T) {
 
 	var call models.Call
-	logger := setupLogger(context.Background(), 10, &call)
+	logger := setupLogger(context.Background(), 10, true, &call)
 
 	str := fmt.Sprintf("0 line\n1 l\n-----max log size 10 bytes exceeded, truncating log-----\n")
 

api/agent/call.go

@@ -431,7 +431,7 @@ func (a *agent) GetCall(opts ...CallOpt) (Call, error) {
 
 	c.handler = a.da
 	c.ct = a
-	c.stderr = setupLogger(c.req.Context(), a.cfg.MaxLogSize, c.Call)
+	c.stderr = setupLogger(c.req.Context(), a.cfg.MaxLogSize, !a.cfg.DisableDebugUserLogs, c.Call)
 	if c.w == nil {
 		// send STDOUT to logs if no writer given (async...)
 		// TODO we could/should probably make this explicit to GetCall, ala 'WithLogger', but it's dupe code (who cares?)

api/agent/config.go

@@ -33,6 +33,7 @@ type Config struct {
 	EnableNBResourceTracker bool          `json:"enable_nb_resource_tracker"`
 	MaxTmpFsInodes          uint64        `json:"max_tmpfs_inodes"`
 	DisableReadOnlyRootFs   bool          `json:"disable_readonly_rootfs"`
+	DisableDebugUserLogs    bool          `json:"disable_debug_user_logs"`
 }
 
 const (
@@ -83,6 +84,8 @@ const (
 	EnvMaxTmpFsInodes = "FN_MAX_TMPFS_INODES"
 	// EnvDisableReadOnlyRootFs makes the root fs for a container have rw permissions, by default it is read only
 	EnvDisableReadOnlyRootFs = "FN_DISABLE_READONLY_ROOTFS"
+	// EnvDisableDebugUserLogs disables user function logs being logged at level debug. wise to enable for production.
+	EnvDisableDebugUserLogs = "FN_DISABLE_DEBUG_USER_LOGS"
 
 	// MaxMsDisabled is used to determine whether mr freeze is lying in wait. TODO remove this manuever
 	MaxMsDisabled = time.Duration(math.MaxInt64)
@@ -137,6 +140,9 @@ func NewConfig() (*Config, error) {
 	if _, ok := os.LookupEnv(EnvDisableReadOnlyRootFs); ok {
 		cfg.DisableReadOnlyRootFs = true
 	}
+	if _, ok := os.LookupEnv(EnvDisableDebugUserLogs); ok {
+		cfg.DisableDebugUserLogs = true
+	}
 
 	if cfg.EjectIdle == time.Duration(0) {
 		return cfg, fmt.Errorf("error %s cannot be zero", EnvEjectIdle)

api/agent/func_logger.go

@@ -25,7 +25,7 @@ var (
 // multiWriteCloser ignores errors. Close will flush the line writers
 // appropriately.  The returned io.ReadWriteCloser is not safe for use after
 // calling Close.
-func setupLogger(ctx context.Context, maxSize uint64, c *models.Call) io.ReadWriteCloser {
+func setupLogger(ctx context.Context, maxSize uint64, debug bool, c *models.Call) io.ReadWriteCloser {
 	lbuf := bufPool.Get().(*bytes.Buffer)
 	dbuf := logPool.Get().(*bytes.Buffer)
 
@@ -41,14 +41,20 @@ func setupLogger(ctx context.Context, maxSize uint64, c *models.Call) io.ReadWri
 	// we don't need to log per line to db, but we do need to limit it
 	limitw := &nopCloser{newLimitWriter(int(maxSize), dbuf)}
 
+	// order matters, in that closer should be last and limit should be next to last
+	mw := make(multiWriteCloser, 0, 3)
+
+	if debug {
 		// accumulate all line writers, wrap in same line writer (to re-use buffer)
 		stderrLogger := common.Logger(ctx).WithFields(logrus.Fields{"user_log": true, "app_id": c.AppID, "path": c.Path, "image": c.Image, "call_id": c.ID})
 		loggo := &nopCloser{&logWriter{stderrLogger}}
 
 		// we don't need to limit the log writer(s), but we do need it to dispense lines
 		linew := newLineWriterWithBuffer(lbuf, loggo)
+		mw = append(mw, linew)
+	}
 
-	mw := multiWriteCloser{linew, limitw, &fCloser{close}}
+	mw = append(mw, limitw, &fCloser{close})
 	return &rwc{mw, dbuf}
 }