Add debug() function to khepri cmd and lib

cmd/khepri/debug.go

@@ -26,7 +26,7 @@ func initDebugLogger() *log.Logger {
 
 	// open logger
 	l := log.New(io.MultiWriter(os.Stderr, f), "DEBUG: ", log.LstdFlags)
-	fmt.Fprintf(os.Stderr, "logging activated, writing log file %s", filename)
+	fmt.Fprintf(os.Stderr, "logging activated, writing log file %s\n", filename)
 	l.Printf("khepri %s", version)
 
 	return l

debug.go

@@ -0,0 +1,38 @@
+// +build debug
+
+package khepri
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"time"
+)
+
+var version = "compiled manually"
+var debugLogger = initDebugLogger()
+
+func initDebugLogger() *log.Logger {
+	// create new log file
+	filename := fmt.Sprintf("khepri-debug-%d-%s",
+		os.Getpid(), time.Now().Format("20060201-150405"))
+	f, err := os.OpenFile(filepath.Join(os.TempDir(), filename),
+		os.O_WRONLY|os.O_CREATE, 0600)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "unable to create debug log file: %v", err)
+		os.Exit(2)
+	}
+
+	// open logger
+	l := log.New(io.MultiWriter(os.Stderr, f), "DEBUG: ", log.LstdFlags)
+	fmt.Fprintf(os.Stderr, "logging activated, writing log file %s\n", filename)
+	l.Printf("khepri %s", version)
+
+	return l
+}
+
+func debug(fmt string, args ...interface{}) {
+	debugLogger.Printf(fmt, args...)
+}

debug_release.go

@@ -0,0 +1,5 @@
+// +build !debug
+
+package khepri
+
+func debug(fmt string, args ...interface{}) {}