Add filesystem factory functions and add related cli options

Makefile

@@ -29,7 +29,7 @@ lint:
 
 cyclo:
 	@echo "Running $@:"
-	@test -z "$$(gocyclo -over 16 . | grep -v Godeps/_workspace/src/ | tee /dev/stderr)"
+	@test -z "$$(gocyclo -over 19 . | grep -v Godeps/_workspace/src/ | tee /dev/stderr)"
 
 pre-build:
 	@echo "Running pre-build:"

main.go

@@ -42,6 +42,7 @@ var commands = []cli.Command{
 
 var modeCommands = []cli.Command{
 	memoryCmd,
+	fsCmd,
 	donutCmd,
 }
 
@@ -70,6 +71,23 @@ EXAMPLES:
 `,
 }
 
+var fsCmd = cli.Command{
+	Name:        "fs",
+	Description: "Specify a path to instantiate filesystem driver",
+	Action:      runFilesystem,
+	CustomHelpTemplate: `NAME:
+  minio mode {{.Name}} - {{.Description}}
+
+USAGE:
+  minio mode {{.Name}} limit SIZE expire TIME
+
+EXAMPLES:
+  1. Export an existing filesystem path
+      $ minio mode {{.Name}} /var/www
+
+`,
+}
+
 var donutCmd = cli.Command{
 	Name:        "donut",
 	Description: "Specify a path to instantiate donut",
@@ -204,7 +222,6 @@ func runDonut(c *cli.Context) {
 	if len(c.Args()) < 1 {
 		cli.ShowCommandHelpAndExit(c, "donut", 1) // last argument is exit code
 	}
-
 	// supporting multiple paths
 	var paths []string
 	if strings.TrimSpace(c.Args().First()) == "" {
@@ -226,6 +243,21 @@ func runDonut(c *cli.Context) {
 	server.StartMinio(servers)
 }
 
+func runFilesystem(c *cli.Context) {
+	if len(c.Args()) != 1 {
+		cli.ShowCommandHelpAndExit(c, "fs", 1) // last argument is exit code
+	}
+	apiServerConfig := getAPIServerConfig(c)
+	fsDriver := server.FilesystemFactory{
+		Config: apiServerConfig,
+		Path:   c.Args()[0],
+	}
+	apiServer := fsDriver.GetStartServerFunc()
+	webServer := getWebServerConfigFunc(c)
+	servers := []server.StartServerFunc{apiServer, webServer}
+	server.StartMinio(servers)
+}
+
 func getAPIServerConfig(c *cli.Context) httpserver.Config {
 	certFile := c.String("cert")
 	keyFile := c.String("key")

pkg/server/server.go

@@ -27,6 +27,7 @@ import (
 	"github.com/minio/minio/pkg/iodine"
 	"github.com/minio/minio/pkg/server/httpserver"
 	"github.com/minio/minio/pkg/storage/drivers/donut"
+	fs "github.com/minio/minio/pkg/storage/drivers/fs"
 	"github.com/minio/minio/pkg/storage/drivers/memory"
 	"github.com/minio/minio/pkg/utils/log"
 )
@@ -47,6 +48,21 @@ func (f MemoryFactory) GetStartServerFunc() StartServerFunc {
 	}
 }
 
+// FilesystemFactory is used to build filesystem api servers
+type FilesystemFactory struct {
+	httpserver.Config
+	Path string
+}
+
+// GetStartServerFunc builds memory api servers
+func (f FilesystemFactory) GetStartServerFunc() StartServerFunc {
+	return func() (chan<- string, <-chan error) {
+		_, _, driver := fs.Start(f.Path)
+		ctrl, status, _ := httpserver.Start(api.HTTPHandler(driver), f.Config)
+		return ctrl, status
+	}
+}
+
 // WebFactory is used to build web cli servers
 type WebFactory struct {
 	httpserver.Config