Fix bug in config.LoadFromFile if file is not present

config/load.go

@@ -56,9 +56,10 @@ func LoadFromString(configString string) (*Config, error) {
 
 func LoadFromFile(fileName string) (*Config, error) {
 	configReader, err := os.Open(fileName)
-	defer configReader.Close()
 	if err != nil {
 		return &Config{}, err
 	}
+	defer configReader.Close()
+
 	return LoadFromReader(configReader)
 }

config/load_test.go

@@ -0,0 +1,25 @@
+// Copyright 2013 Prometheus Team
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+  "testing"
+)
+
+func TestLoadFromFile(t *testing.T) {
+  _, err := LoadFromFile("file-does-not-exist.conf")
+  if err == nil {
+    t.Error(err)
+  }
+}

main.go

@@ -39,7 +39,7 @@ func main() {
 	flag.Parse()
 	conf, err := config.LoadFromFile(*configFile)
 	if err != nil {
-		log.Fatalf("Error loading configuration from %s: %v", configFile, err)
+		log.Fatalf("Error loading configuration from %s: %v", *configFile, err)
 	}
 
 	persistence, err := leveldb.NewLevelDBMetricPersistence(*metricsStoragePath)