Add Redis support for Distributed Filer store.

docs/distributed_filer.rst

@@ -10,7 +10,11 @@ However, no SPOF is a must-have requirement for many projects.
 Luckily, SeaweedFS is so flexible that we can use a completely different way
 to manage file metadata.
 
-This distributed filer uses Cassandra to store the metadata.
+This distributed filer uses Redis or Cassandra to store the metadata.
+
+Redis Setup
+#####################
+No setup required.
 
 Cassandra Setup
 #####################
@@ -37,7 +41,14 @@ For production server, you would want to set replication_factor to 3.
 Sample usage
 #####################
 
-To start a weed filer in distributed mode:
+To start a weed filer in distributed mode with Redis:
+
+.. code-block:: bash
+
+	# assuming you already started weed master and weed volume
+	weed filer -redis.server=localhost:6379
+
+To start a weed filer in distributed mode with Cassandra:
 
 .. code-block:: bash
 
@@ -57,8 +68,8 @@ Now you can add/delete files
 
 Limitation
 ############
-List sub folders and files are not supported because Cassandra does not support
-prefix search.
+List sub folders and files are not supported because Redis or Cassandra
+does not support prefix search.
 
 Flat Namespace Design
 ############
@@ -73,16 +84,16 @@ A flat namespace would take more space because the parent directories are
 repeatedly stored. But disk space is a lesser concern especially for
 distributed systems.
 
-The Cassandra table is a simple file_full_path ~ file_id mapping. Actually
-it is a file_full_path ~ list_of_file_ids mapping with the hope to support
-easy file appending for streaming files.
+So either Redis or Cassandra is a simple file_full_path ~ file_id mapping.
+(Actually Cassandra is a file_full_path ~ list_of_file_ids mapping
+with the hope to support easy file appending for streaming files.)
 
 Complexity
 ###################
 
 For one file retrieval, the full_filename=>file_id lookup will be O(logN)
-using Cassandra. But very likely the one additional network hop would
-take longer than the Cassandra internal lookup.
+using Redis or Cassandra. But very likely the one additional network hop would
+take longer than the actual lookup.
 
 Use Cases
 #########################
@@ -93,7 +104,7 @@ read files via HTTP POST directly.
 Future
 ###################
 
-SeaweedFS can support additional distributed databases. It will be better
+SeaweedFS can support other distributed databases. It will be better
 if that database can support prefix search, in order to list files
 under a directory.
 

go/filer/redis_store/redis_store.go

@@ -0,0 +1,48 @@
+package redis_store
+
+import (
+	redis "gopkg.in/redis.v2"
+)
+
+type RedisStore struct {
+	Client *redis.Client
+}
+
+func NewRedisStore(hostPort string, database int) *RedisStore {
+	client := redis.NewTCPClient(&redis.Options{
+		Addr:     hostPort,
+		Password: "", // no password set
+		DB:       int64(database),
+	})
+	return &RedisStore{Client: client}
+}
+
+func (s *RedisStore) Get(fullFileName string) (fid string, err error) {
+	fid, err = s.Client.Get(fullFileName).Result()
+	if err == redis.Nil {
+		err = nil
+	}
+	return fid, err
+}
+func (s *RedisStore) Put(fullFileName string, fid string) (err error) {
+	_, err = s.Client.Set(fullFileName, fid).Result()
+	if err == redis.Nil {
+		err = nil
+	}
+	return err
+}
+
+// Currently the fid is not returned
+func (s *RedisStore) Delete(fullFileName string) (fid string, err error) {
+	_, err = s.Client.Del(fullFileName).Result()
+	if err == redis.Nil {
+		err = nil
+	}
+	return "", err
+}
+
+func (c *RedisStore) Close() {
+	if c.Client != nil {
+		c.Client.Close()
+	}
+}

go/weed/filer.go

@@ -24,6 +24,8 @@ type FilerOptions struct {
 	redirectOnRead          *bool
 	cassandra_server        *string
 	cassandra_keyspace      *string
+	redis_server            *string
+	redis_database          *int
 }
 
 func init() {
@@ -36,6 +38,8 @@ func init() {
 	f.redirectOnRead = cmdFiler.Flag.Bool("redirectOnRead", false, "whether proxy or redirect to volume server during file GET request")
 	f.cassandra_server = cmdFiler.Flag.String("cassandra.server", "", "host[:port] of the cassandra server")
 	f.cassandra_keyspace = cmdFiler.Flag.String("cassandra.keyspace", "seaweed", "keyspace of the cassandra server")
+	f.redis_server = cmdFiler.Flag.String("redis.server", "", "host:port of the cassandra server, e.g., 127.0.0.1:6379")
+	f.redis_database = cmdFiler.Flag.Int("redis.database", 0, "the database on the redis server")
 }
 
 var cmdFiler = &Command{
@@ -70,6 +74,7 @@ func runFiler(cmd *Command, args []string) bool {
 	_, nfs_err := weed_server.NewFilerServer(r, *f.port, *f.master, *f.dir, *f.collection,
 		*f.defaultReplicaPlacement, *f.redirectOnRead,
 		*f.cassandra_server, *f.cassandra_keyspace,
+		*f.redis_server, *f.redis_database,
 	)
 	if nfs_err != nil {
 		glog.Fatalf(nfs_err.Error())

go/weed/server.go

@@ -160,6 +160,7 @@ func runServer(cmd *Command, args []string) bool {
 			_, nfs_err := weed_server.NewFilerServer(r, *filerOptions.port, *filerOptions.master, *filerOptions.dir, *filerOptions.collection,
 				*filerOptions.defaultReplicaPlacement, *filerOptions.redirectOnRead,
 				"", "",
+				"", 0,
 			)
 			if nfs_err != nil {
 				glog.Fatalf(nfs_err.Error())

go/weed/weed_server/filer_server.go

@@ -8,6 +8,7 @@ import (
 	"github.com/chrislusf/weed-fs/go/filer/cassandra_store"
 	"github.com/chrislusf/weed-fs/go/filer/embedded_filer"
 	"github.com/chrislusf/weed-fs/go/filer/flat_namespace"
+	"github.com/chrislusf/weed-fs/go/filer/redis_store"
 	"github.com/chrislusf/weed-fs/go/glog"
 )
 
@@ -23,6 +24,7 @@ type FilerServer struct {
 func NewFilerServer(r *http.ServeMux, port int, master string, dir string, collection string,
 	replication string, redirectOnRead bool,
 	cassandra_server string, cassandra_keyspace string,
+	redis_server string, redis_database int,
 ) (fs *FilerServer, err error) {
 	fs = &FilerServer{
 		master:             master,
@@ -32,19 +34,22 @@ func NewFilerServer(r *http.ServeMux, port int, master string, dir string, colle
 		port:               ":" + strconv.Itoa(port),
 	}
 
-	if cassandra_server == "" {
+	if cassandra_server != "" {
+		cassandra_store, err := cassandra_store.NewCassandraStore(cassandra_keyspace, cassandra_server)
+		if err != nil {
+			glog.Fatalf("Can not connect to cassandra server %s with keyspace %s: %v", cassandra_server, cassandra_keyspace, err)
+		}
+		fs.filer = flat_namespace.NewFlatNamesapceFiler(master, cassandra_store)
+	} else if redis_server != "" {
+		redis_store := redis_store.NewRedisStore(redis_server, redis_database)
+		fs.filer = flat_namespace.NewFlatNamesapceFiler(master, redis_store)
+	} else {
 		if fs.filer, err = embedded_filer.NewFilerEmbedded(master, dir); err != nil {
 			glog.Fatalf("Can not start filer in dir %s : %v", err)
 			return
 		}
 
 		r.HandleFunc("/admin/mv", fs.moveHandler)
-	} else {
-		cassandra_store, err := cassandra_store.NewCassandraStore(cassandra_keyspace, cassandra_server)
-		if err != nil {
-			glog.Fatalf("Can not connect to cassandra server %s with keyspace %s: %v", cassandra_server, cassandra_keyspace, err)
-		}
-		fs.filer = flat_namespace.NewFlatNamesapceFiler(master, cassandra_store)
 	}
 
 	r.HandleFunc("/", fs.filerHandler)