support multiple drivers on single socket

README.md

@@ -11,3 +11,18 @@ A collection of helper packages to extend Docker Engine in Go
  Graph (experimental) | [Link](https://github.com/docker/docker/blob/master/experimental/plugins_graphdriver.md) | Extend image and container fs storage
 
 See the [understand Docker plugins documentation section](https://docs.docker.com/engine/extend/plugins/).
+
+# Serving multiple drivers on a single socket
+```go
+import (
+    "github.com/docker/go-plugins-helpers/sdk"
+    "github.com/docker/go-plugins-helpers/ipam"
+    "github.com/docker/go-plugins-helpers/network"
+)
+dIPAM := MyIPAMDriver{}
+dNetwork := MyNetworkDriver{}
+h := sdk.NewHandler()
+ipam.RegisterDriver(dIPAM, h)
+network.RegisterDriver(dNetwork,h)
+h.ServeUnix("/var/run/docker/plugins/myplugin.sock", 1001)
+```

authorization/api.go

@@ -9,9 +9,8 @@ import (
 )
 
 const (
-	manifest = `{"Implements": ["` + authorization.AuthZApiImplements + `"]}`
-	reqPath  = "/" + authorization.AuthZApiRequest
-	resPath  = "/" + authorization.AuthZApiResponse
+	reqPath = "/" + authorization.AuthZApiRequest
+	resPath = "/" + authorization.AuthZApiResponse
 )
 
 // Request is the structure that docker's requests are deserialized to.
@@ -26,32 +25,33 @@ type Plugin interface {
 	AuthZRes(Request) Response
 }
 
-// Handler forwards requests and responses between the docker daemon and the plugin.
-type Handler struct {
-	plugin Plugin
-	sdk.Handler
-}
-
 // NewHandler initializes the request handler with a plugin implementation.
-func NewHandler(plugin Plugin) *Handler {
-	h := &Handler{plugin, sdk.NewHandler(manifest)}
-	h.initMux()
+func NewHandler(plugin Plugin) *sdk.Handler {
+	h := sdk.NewHandler()
+	RegisterDriver(plugin, h)
 	return h
 }
 
-func (h *Handler) initMux() {
-	h.handle(reqPath, func(req Request) Response {
-		return h.plugin.AuthZReq(req)
+// RegisterDriver registers the plugin to the SDK handler.
+func RegisterDriver(plugin Plugin, h *sdk.Handler) {
+	h.RegisterDriver(authorization.AuthZApiImplements, func(h *sdk.Handler) {
+		initMux(plugin, h)
+	})
+}
+
+func initMux(plugin Plugin, h *sdk.Handler) {
+	handle(h, reqPath, func(req Request) Response {
+		return plugin.AuthZReq(req)
 	})
 
-	h.handle(resPath, func(req Request) Response {
-		return h.plugin.AuthZRes(req)
+	handle(h, resPath, func(req Request) Response {
+		return plugin.AuthZRes(req)
 	})
 }
 
 type actionHandler func(Request) Response
 
-func (h *Handler) handle(name string, actionCall actionHandler) {
+func handle(h *sdk.Handler, name string, actionCall actionHandler) {
 	h.HandleFunc(name, func(w http.ResponseWriter, r *http.Request) {
 		var (
 			req Request

authorization/api_test.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/docker/docker/pkg/authorization"
 	"github.com/docker/go-plugins-helpers/sdk"
 )
 
@@ -46,8 +47,8 @@ func TestActivate(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if string(body) != manifest+"\n" {
-		t.Fatalf("Expected %s, got %s\n", manifest+"\n", string(body))
+	if !strings.Contains(string(body), authorization.AuthZApiImplements) {
+		t.Fatalf("Expected driver to implement %s, got %s\n", authorization.AuthZApiImplements, string(body))
 	}
 }
 

graphdriver/api.go

@@ -16,7 +16,7 @@ const (
 	// DefaultDockerRootDirectory is the default directory where graph drivers will be created.
 	DefaultDockerRootDirectory = "/var/lib/docker/graph"
 
-	manifest        = `{"Implements": ["GraphDriver"]}`
+	driverName      = "GraphDriver"
 	initPath        = "/GraphDriver.Init"
 	createPath      = "/GraphDriver.Create"
 	createRWPath    = "/GraphDriver.CreateReadWrite"
@@ -238,27 +238,28 @@ type Driver interface {
 	DiffSize(id, parent string) (int64, error)
 }
 
-// Handler forwards requests and responses between the docker daemon and the plugin.
-type Handler struct {
-	driver Driver
-	sdk.Handler
-}
-
 // NewHandler initializes the request handler with a driver implementation.
-func NewHandler(driver Driver) *Handler {
-	h := &Handler{driver, sdk.NewHandler(manifest)}
-	h.initMux()
+func NewHandler(driver Driver) *sdk.Handler {
+	h := sdk.NewHandler()
+	RegisterDriver(driver, h)
 	return h
 }
 
-func (h *Handler) initMux() {
+// RegisterDriver registers the plugin to the SDK handler.
+func RegisterDriver(driver Driver, h *sdk.Handler) {
+	h.RegisterDriver(driverName, func(h *sdk.Handler) {
+		initMux(driver, h)
+	})
+}
+
+func initMux(driver Driver, h *sdk.Handler) {
 	h.HandleFunc(initPath, func(w http.ResponseWriter, r *http.Request) {
 		req := InitRequest{}
 		err := sdk.DecodeRequest(w, r, &req)
 		if err != nil {
 			return
 		}
-		err = h.driver.Init(req.Home, req.Options, req.UIDMaps, req.GIDMaps)
+		err = driver.Init(req.Home, req.Options, req.UIDMaps, req.GIDMaps)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -271,7 +272,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.driver.Create(req.ID, req.Parent, req.MountLabel, req.StorageOpt)
+		err = driver.Create(req.ID, req.Parent, req.MountLabel, req.StorageOpt)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -284,7 +285,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.driver.CreateReadWrite(req.ID, req.Parent, req.MountLabel, req.StorageOpt)
+		err = driver.CreateReadWrite(req.ID, req.Parent, req.MountLabel, req.StorageOpt)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -297,7 +298,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.driver.Remove(req.ID)
+		err = driver.Remove(req.ID)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -311,7 +312,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		dir, err := h.driver.Get(req.ID, req.MountLabel)
+		dir, err := driver.Get(req.ID, req.MountLabel)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -324,7 +325,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.driver.Put(req.ID)
+		err = driver.Put(req.ID)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -337,11 +338,11 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		exists := h.driver.Exists(req.ID)
+		exists := driver.Exists(req.ID)
 		sdk.EncodeResponse(w, &ExistsResponse{Exists: exists}, "")
 	})
 	h.HandleFunc(statusPath, func(w http.ResponseWriter, r *http.Request) {
-		status := h.driver.Status()
+		status := driver.Status()
 		sdk.EncodeResponse(w, &StatusResponse{Status: status}, "")
 	})
 	h.HandleFunc(getMetadataPath, func(w http.ResponseWriter, r *http.Request) {
@@ -350,15 +351,15 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		metadata, err := h.driver.GetMetadata(req.ID)
+		metadata, err := driver.GetMetadata(req.ID)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
 		}
 		sdk.EncodeResponse(w, &GetMetadataResponse{Err: msg, Metadata: metadata}, msg)
 	})
 	h.HandleFunc(cleanupPath, func(w http.ResponseWriter, r *http.Request) {
-		err := h.driver.Cleanup()
+		err := driver.Cleanup()
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -371,7 +372,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		stream := h.driver.Diff(req.ID, req.Parent)
+		stream := driver.Diff(req.ID, req.Parent)
 		sdk.StreamResponse(w, stream)
 	})
 	h.HandleFunc(changesPath, func(w http.ResponseWriter, r *http.Request) {
@@ -380,7 +381,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		changes, err := h.driver.Changes(req.ID, req.Parent)
+		changes, err := driver.Changes(req.ID, req.Parent)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -391,7 +392,7 @@ func (h *Handler) initMux() {
 		params := r.URL.Query()
 		id := params.Get("id")
 		parent := params.Get("parent")
-		size, err := h.driver.ApplyDiff(id, parent, r.Body)
+		size, err := driver.ApplyDiff(id, parent, r.Body)
 		msg := ""
 		if err != nil {
 			msg = err.Error()
@@ -404,7 +405,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		size, err := h.driver.DiffSize(req.ID, req.Parent)
+		size, err := driver.DiffSize(req.ID, req.Parent)
 		msg := ""
 		if err != nil {
 			msg = err.Error()

graphdriver/shim/shim.go

@@ -9,6 +9,7 @@ import (
 	"github.com/docker/docker/pkg/archive"
 	"github.com/docker/docker/pkg/idtools"
 	graphPlugin "github.com/docker/go-plugins-helpers/graphdriver"
+	"github.com/docker/go-plugins-helpers/sdk"
 )
 
 type shimDriver struct {
@@ -21,7 +22,7 @@ type shimDriver struct {
 // built-in to Docker Engine and it would create a plugin from it that maps
 // plugin API calls directly to any volume driver that satifies the
 // graphdriver.Driver interface from Docker Engine.
-func NewHandlerFromGraphDriver(init graphDriver.InitFunc) *graphPlugin.Handler {
+func NewHandlerFromGraphDriver(init graphDriver.InitFunc) *sdk.Handler {
 	return graphPlugin.NewHandler(&shimDriver{driver: nil, init: init})
 }
 

ipam/api.go

@@ -7,7 +7,7 @@ import (
 )
 
 const (
-	manifest = `{"Implements": ["IpamDriver"]}`
+	driverName = "IpamDriver"
 
 	capabilitiesPath   = "/IpamDriver.GetCapabilities"
 	addressSpacesPath  = "/IpamDriver.GetDefaultAddressSpaces"
@@ -88,22 +88,23 @@ func NewErrorResponse(msg string) *ErrorResponse {
 	return &ErrorResponse{Err: msg}
 }
 
-// Handler forwards requests and responses between the docker daemon and the plugin.
-type Handler struct {
-	ipam Ipam
-	sdk.Handler
-}
-
 // NewHandler initializes the request handler with a driver implementation.
-func NewHandler(ipam Ipam) *Handler {
-	h := &Handler{ipam, sdk.NewHandler(manifest)}
-	h.initMux()
+func NewHandler(ipam Ipam) *sdk.Handler {
+	h := sdk.NewHandler()
+	RegisterDriver(ipam, h)
 	return h
 }
 
-func (h *Handler) initMux() {
+// RegisterDriver registers the plugin to the SDK handler.
+func RegisterDriver(ipam Ipam, h *sdk.Handler) {
+	h.RegisterDriver(driverName, func(h *sdk.Handler) {
+		initMux(ipam, h)
+	})
+}
+
+func initMux(ipam Ipam, h *sdk.Handler) {
 	h.HandleFunc(capabilitiesPath, func(w http.ResponseWriter, r *http.Request) {
-		res, err := h.ipam.GetCapabilities()
+		res, err := ipam.GetCapabilities()
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)
@@ -112,7 +113,7 @@ func (h *Handler) initMux() {
 		sdk.EncodeResponse(w, res, "")
 	})
 	h.HandleFunc(addressSpacesPath, func(w http.ResponseWriter, r *http.Request) {
-		res, err := h.ipam.GetDefaultAddressSpaces()
+		res, err := ipam.GetDefaultAddressSpaces()
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)
@@ -126,7 +127,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		res, err := h.ipam.RequestPool(req)
+		res, err := ipam.RequestPool(req)
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)
@@ -140,7 +141,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.ipam.ReleasePool(req)
+		err = ipam.ReleasePool(req)
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)
@@ -154,7 +155,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		res, err := h.ipam.RequestAddress(req)
+		res, err := ipam.RequestAddress(req)
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)
@@ -168,7 +169,7 @@ func (h *Handler) initMux() {
 		if err != nil {
 			return
 		}
-		err = h.ipam.ReleaseAddress(req)
+		err = ipam.ReleaseAddress(req)
 		if err != nil {
 			msg := err.Error()
 			sdk.EncodeResponse(w, NewErrorResponse(msg), msg)