Merge pull request elastic#99 from tsg/use_beat_name_for_config

Use the Beat name in the default configuration file path

beat/beat.go

@@ -59,6 +59,13 @@ func NewBeat(name string, version string, bt Beater) *Beat {
 // To set additional cmd line args use the beat.CmdLine type before calling the function
 func (beat *Beat) CommandLineSetup() {
 
+	// The -c flag is treated separately because it needs the Beat name
+	err := cfgfile.ChangeDefaultCfgfileFlag(beat.Name)
+	if err != nil {
+		fmt.Printf("Failed to fix the -c flag: %v\n", err)
+		os.Exit(1)
+	}
+
 	flag.Parse()
 
 	if *printVersion {

cfgfile/cfgfile.go

@@ -13,11 +13,23 @@ var configfile *string
 var testConfig *bool
 
 func init() {
-	// The default config cannot include the beat name as it is not initialised when this function is called
+	// The default config cannot include the beat name as it is not initialised when this
+	// function is called, but see ChangeDefaultCfgfileFlag
 	configfile = flag.String("c", "/etc/beat/beat.yml", "Configuration file")
 	testConfig = flag.Bool("test", false, "Test configuration and exit.")
 }
 
+// ChangeDefaultCfgfileFlag replaces the value and default value for the `-c` flag so that
+// it reflects the beat name.
+func ChangeDefaultCfgfileFlag(beatName string) error {
+	cliflag := flag.Lookup("c")
+	if cliflag == nil {
+		return fmt.Errorf("Flag -c not found")
+	}
+	cliflag.DefValue = fmt.Sprintf("/etc/%s/%s.yml", beatName, beatName)
+	return cliflag.Value.Set(cliflag.DefValue)
+}
+
 // Read reads the configuration from a yaml file into the given interface structure.
 // In case path is not set this method reads from the default configuration file for the beat.
 func Read(out interface{}, path string) error {