containermetadata: extract duplicated parsing code

agent/containermetadata/manager.go

@@ -114,13 +114,7 @@ func (manager *metadataManager) Create(config *docker.Config, hostConfig *docker
 
 	// Acquire the metadata then write it in JSON format to the file
 	metadata := manager.parseMetadataAtContainerCreate(taskARN, containerName)
-	data, err := json.MarshalIndent(metadata, "", "\t")
-	if err != nil {
-		return fmt.Errorf("create metadata for task %s container %s: %v", taskARN, containerName, err)
-	}
-
-	// Write the metadata to file
-	err = writeToMetadataFile(manager.osWrap, manager.ioutilWrap, data, taskARN, containerName, manager.dataDir)
+	err = manager.marshalAndWrite(metadata, taskARN, containerName)
 	if err != nil {
 		return err
 	}
@@ -148,12 +142,11 @@ func (manager *metadataManager) Update(dockerID string, taskARN string, containe
 
 	// Acquire the metadata then write it in JSON format to the file
 	metadata := manager.parseMetadata(dockerContainer, taskARN, containerName)
-	data, err := json.MarshalIndent(metadata, "", "\t")
+	err = manager.marshalAndWrite(metadata, taskARN, containerName)
 	if err != nil {
-		return fmt.Errorf("update metadata for task %s container %s: %v", taskARN, containerName, err)
+		return err
 	}
-
-	return writeToMetadataFile(manager.osWrap, manager.ioutilWrap, data, taskARN, containerName, manager.dataDir)
+	return nil
 }
 
 // Clean removes the metadata files of all containers associated with a task
@@ -164,3 +157,18 @@ func (manager *metadataManager) Clean(taskARN string) error {
 	}
 	return manager.osWrap.RemoveAll(metadataPath)
 }
+
+func (manager *metadataManager) marshalAndWrite(metadata Metadata, taskARN string, containerName string) error {
+	data, err := json.MarshalIndent(metadata, "", "\t")
+	if err != nil {
+		return fmt.Errorf("create metadata for task %s container %s: %v", taskARN, containerName, err)
+	}
+
+	// Write the metadata to file
+	err = writeToMetadataFile(manager.osWrap, manager.ioutilWrap, data, taskARN, containerName, manager.dataDir)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

agent/containermetadata/write_metadata_unix.go

@@ -27,6 +27,7 @@ import (
 
 const (
 	mountPoint = "/opt/ecs/metadata"
+	tempFile   = "temp_metadata_file"
 )
 
 // createBindsEnv will do the appropriate formatting to add a new mount in a container's HostConfig
@@ -51,7 +52,7 @@ func writeToMetadataFile(osWrap oswrapper.OS, ioutilWrap ioutilwrapper.IOUtil, d
 	}
 	metadataFileName := filepath.Join(metadataFileDir, metadataFile)
 
-	temp, err := ioutilWrap.TempFile(metadataFileDir, "temp_metadata_file")
+	temp, err := ioutilWrap.TempFile(metadataFileDir, tempFile)
 	if err != nil {
 		return err
 	}