From a3e5121f7bb41a036d86d0c82af30e3192687851 Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@harshavardhana.net>
Date: Tue, 17 Feb 2015 23:48:42 -0800
Subject: [PATCH] Make channels more aware of errors and shutdown on error -
 some cleanup

---
 pkg/server/server.go | 29 ++++++++++++++---------------
 pkg/storage/fs/fs.go | 38 ++++++++++++++++++--------------------
 2 files changed, 32 insertions(+), 35 deletions(-)

diff --git a/pkg/server/server.go b/pkg/server/server.go
index 1b44e0203..3aad8bf90 100644
--- a/pkg/server/server.go
+++ b/pkg/server/server.go
@@ -18,7 +18,6 @@ package server
 
 import (
 	"log"
-	"os"
 	"path"
 	"reflect"
 
@@ -129,14 +128,8 @@ func getStorageChannels(storageType StorageType) (ctrlChans []chan<- string, sta
 	case storageType == FileStorage:
 		{
 			homeDir := helpers.HomeDir()
-			rootPath := path.Join(homeDir, "minio-storage")
-			_, err := os.Stat(rootPath)
-			if os.IsNotExist(err) {
-				err = os.Mkdir(rootPath, 0700)
-			} else if err != nil {
-				log.Fatal("Could not create $HOME/minio-storage", err)
-			}
-			ctrlChan, statusChan, storage = fs.Start(rootPath)
+			root := path.Join(homeDir, "minio-storage")
+			ctrlChan, statusChan, storage = fs.Start(root)
 			ctrlChans = append(ctrlChans, ctrlChan)
 			statusChans = append(statusChans, statusChan)
 		}
@@ -147,17 +140,23 @@ func getStorageChannels(storageType StorageType) (ctrlChans []chan<- string, sta
 }
 
 func Start(configs []ServerConfig) {
-	// listen for critical errors
-	// TODO Handle critical errors appropriately when they arise
 	// reflected looping is necessary to remove dead channels from loop and not flood switch
-	_, statusChans := getHttpChannels(configs)
+	ctrlChans, statusChans := getHttpChannels(configs)
 	cases := createSelectCases(statusChans)
 	for len(cases) > 0 {
 		chosen, value, recvOk := reflect.Select(cases)
-		if recvOk == true {
+		switch recvOk {
+		case true:
 			// Status Message Received
-			log.Println(chosen, value.Interface(), recvOk)
-		} else {
+			switch true {
+			case value.Interface() != nil:
+				// For any error received cleanup all existing channels and fail
+				for _, ch := range ctrlChans {
+					close(ch)
+				}
+				log.Fatal(value.Interface())
+			}
+		case false:
 			// Channel closed, remove from list
 			var aliveStatusChans []<-chan error
 			for i, ch := range statusChans {
diff --git a/pkg/storage/fs/fs.go b/pkg/storage/fs/fs.go
index bd8df7116..3d0c08dba 100644
--- a/pkg/storage/fs/fs.go
+++ b/pkg/storage/fs/fs.go
@@ -31,33 +31,31 @@ import (
 )
 
 type storage struct {
-	root      string
-	writeLock sync.Mutex
+	root string
+	lock *sync.Mutex
 }
 
 type SerializedMetadata struct {
 	ContentType string
 }
 
-type MkdirFailedError struct{}
-
-func (self MkdirFailedError) Error() string {
-	return "Mkdir Failed"
-}
-
 func Start(root string) (chan<- string, <-chan error, *storage) {
 	ctrlChannel := make(chan string)
 	errorChannel := make(chan error)
-	go start(ctrlChannel, errorChannel)
-	return ctrlChannel, errorChannel, &storage{root: root}
+	s := storage{}
+	s.root = root
+	s.lock = new(sync.Mutex)
+	go start(ctrlChannel, errorChannel, &s)
+	return ctrlChannel, errorChannel, &s
 }
 
-func start(ctrlChannel <-chan string, errorChannel chan<- error) {
+func start(ctrlChannel <-chan string, errorChannel chan<- error, s *storage) {
+	err := os.MkdirAll(s.root, 0700)
+	errorChannel <- err
 	close(errorChannel)
 }
 
 // Bucket Operations
-
 func (storage *storage) ListBuckets() ([]mstorage.BucketMetadata, error) {
 	files, err := ioutil.ReadDir(storage.root)
 	if err != nil {
@@ -83,8 +81,8 @@ func (storage *storage) ListBuckets() ([]mstorage.BucketMetadata, error) {
 }
 
 func (storage *storage) StoreBucket(bucket string) error {
-	storage.writeLock.Lock()
-	defer storage.writeLock.Unlock()
+	storage.lock.Lock()
+	defer storage.lock.Unlock()
 
 	// verify bucket path legal
 	if mstorage.IsValidBucket(bucket) == false {
@@ -110,8 +108,8 @@ func (storage *storage) StoreBucket(bucket string) error {
 }
 
 func (storage *storage) GetBucketPolicy(bucket string) (interface{}, error) {
-	storage.writeLock.Lock()
-	defer storage.writeLock.Unlock()
+	storage.lock.Lock()
+	defer storage.lock.Unlock()
 
 	var p policy.BucketPolicy
 	// verify bucket path legal
@@ -153,8 +151,8 @@ func (storage *storage) GetBucketPolicy(bucket string) (interface{}, error) {
 }
 
 func (storage *storage) StoreBucketPolicy(bucket string, policy interface{}) error {
-	storage.writeLock.Lock()
-	defer storage.writeLock.Unlock()
+	storage.lock.Lock()
+	defer storage.lock.Unlock()
 
 	// verify bucket path legal
 	if mstorage.IsValidBucket(bucket) == false {
@@ -332,8 +330,8 @@ func (storage *storage) ListObjects(bucket, prefix string, count int) ([]mstorag
 
 func (storage *storage) StoreObject(bucket, key, contentType string, data io.Reader) error {
 	// TODO Commits should stage then move instead of writing directly
-	storage.writeLock.Lock()
-	defer storage.writeLock.Unlock()
+	storage.lock.Lock()
+	defer storage.lock.Unlock()
 
 	// check bucket name valid
 	if mstorage.IsValidBucket(bucket) == false {