Merge pull request #66 from vincepri/defaults-once

Set default values only once

klog.go

@@ -404,21 +404,36 @@ func init() {
 	go logging.flushDaemon()
 }
 
-// InitFlags is for explicitly initializing the flags
+var initDefaultsOnce sync.Once
+
+// InitFlags is for explicitly initializing the flags.
 func InitFlags(flagset *flag.FlagSet) {
+
+	// Initialize defaults.
+	initDefaultsOnce.Do(func() {
+		logging.logDir = ""
+		logging.logFile = ""
+		logging.logFileMaxSizeMB = 1800
+		logging.toStderr = true
+		logging.alsoToStderr = false
+		logging.skipHeaders = false
+		logging.skipLogHeaders = false
+	})
+
 	if flagset == nil {
 		flagset = flag.CommandLine
 	}
-	flagset.StringVar(&logging.logDir, "log_dir", "", "If non-empty, write log files in this directory")
-	flagset.StringVar(&logging.logFile, "log_file", "", "If non-empty, use this log file")
-	flagset.Uint64Var(&logging.logFileMaxSizeMB, "log_file_max_size", 1800,
+
+	flagset.StringVar(&logging.logDir, "log_dir", logging.logDir, "If non-empty, write log files in this directory")
+	flagset.StringVar(&logging.logFile, "log_file", logging.logFile, "If non-empty, use this log file")
+	flagset.Uint64Var(&logging.logFileMaxSizeMB, "log_file_max_size", logging.logFileMaxSizeMB,
 		"Defines the maximum size a log file can grow to. Unit is megabytes. "+
 			"If the value is 0, the maximum file size is unlimited.")
-	flagset.BoolVar(&logging.toStderr, "logtostderr", true, "log to standard error instead of files")
-	flagset.BoolVar(&logging.alsoToStderr, "alsologtostderr", false, "log to standard error as well as files")
+	flagset.BoolVar(&logging.toStderr, "logtostderr", logging.toStderr, "log to standard error instead of files")
+	flagset.BoolVar(&logging.alsoToStderr, "alsologtostderr", logging.alsoToStderr, "log to standard error as well as files")
 	flagset.Var(&logging.verbosity, "v", "number for the log level verbosity")
-	flagset.BoolVar(&logging.skipHeaders, "skip_headers", false, "If true, avoid header prefixes in the log messages")
-	flagset.BoolVar(&logging.skipLogHeaders, "skip_log_headers", false, "If true, avoid headers when opening log files")
+	flagset.BoolVar(&logging.skipHeaders, "skip_headers", logging.skipHeaders, "If true, avoid header prefixes in the log messages")
+	flagset.BoolVar(&logging.skipLogHeaders, "skip_log_headers", logging.skipLogHeaders, "If true, avoid headers when opening log files")
 	flagset.Var(&logging.stderrThreshold, "stderrthreshold", "logs at or above this threshold go to stderr")
 	flagset.Var(&logging.vmodule, "vmodule", "comma-separated list of pattern=N settings for file-filtered logging")
 	flagset.Var(&logging.traceLocation, "log_backtrace_at", "when logging hits line file:N, emit a stack trace")

klog_test.go

@@ -18,6 +18,7 @@ package klog
 
 import (
 	"bytes"
+	"flag"
 	"fmt"
 	"io/ioutil"
 	stdLog "log"
@@ -533,3 +534,19 @@ func TestFileSizeCheck(t *testing.T) {
 		}
 	}
 }
+
+func TestInitFlags(t *testing.T) {
+	fs1 := flag.NewFlagSet("test1", flag.PanicOnError)
+	InitFlags(fs1)
+	fs1.Set("log_dir", "/test1")
+	fs1.Set("log_file_max_size", "1")
+	fs2 := flag.NewFlagSet("test2", flag.PanicOnError)
+	InitFlags(fs2)
+	if logging.logDir != "/test1" {
+		t.Fatalf("Expected log_dir to be %q, got %q", "/test1", logging.logDir)
+	}
+	fs2.Set("log_file_max_size", "2048")
+	if logging.logFileMaxSizeMB != 2048 {
+		t.Fatal("Expected log_file_max_size to be 2048")
+	}
+}