Merge pull request #2931 from MichaelEischer/reduce-debug-overhead

Reduce debug log overhead

internal/debug/debug.go

@@ -17,9 +17,10 @@ import (
 )
 
 var opts struct {
-	logger *log.Logger
+	isEnabled bool
-	funcs  map[string]bool
+	logger    *log.Logger
-	files  map[string]bool
+	funcs     map[string]bool
+	files     map[string]bool
 }
 
 // make sure that all the initialization happens before the init() functions
@@ -30,6 +31,12 @@ func initDebug() bool {
 	initDebugLogger()
 	initDebugTags()
 
+	if opts.logger == nil && len(opts.funcs) == 0 && len(opts.files) == 0 {
+		opts.isEnabled = false
+		return false
+	}
+
+	opts.isEnabled = true
 	fmt.Fprintf(os.Stderr, "debug enabled\n")
 
 	return true
@@ -173,6 +180,10 @@ func checkFilter(filter map[string]bool, key string) bool {
 
 // Log prints a message to the debug log (if debug is enabled).
 func Log(f string, args ...interface{}) {
+	if !opts.isEnabled {
+		return
+	}
+
 	fn, dir, file, line := getPosition()
 	goroutine := goroutineNum()
 

internal/debug/round_tripper_debug.go

@@ -66,7 +66,12 @@ type loggingRoundTripper struct {
 // RoundTripper returns a new http.RoundTripper which logs all requests (if
 // debug is enabled). When debug is not enabled, upstream is returned.
 func RoundTripper(upstream http.RoundTripper) http.RoundTripper {
-	return loggingRoundTripper{eofDetectRoundTripper{upstream}}
+	eofRoundTripper := eofDetectRoundTripper{upstream}
+	if opts.isEnabled {
+		// only use loggingRoundTripper if the debug log is configured
+		return loggingRoundTripper{eofRoundTripper}
+	}
+	return eofRoundTripper
 }
 
 func (tr loggingRoundTripper) RoundTrip(req *http.Request) (res *http.Response, err error) {