@@ -4,10 +4,9 @@ import (

 	"encoding/json"

 	"net/http"

-	"golang.org/x/net/context"

-

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/cliconfig"

+	"github.com/docker/docker/context"

 )

 func (s *Server) postAuth(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

@@ -8,15 +8,14 @@ import (

 	"strings"

 	"time"

-	"golang.org/x/net/context"

 	"golang.org/x/net/websocket"

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/context"

 	"github.com/docker/docker/daemon"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/signal"

-	"github.com/docker/docker/pkg/version"

 	"github.com/docker/docker/runconfig"

 )

@@ -251,7 +250,7 @@ func (s *Server) postContainersKill(ctx context.Context, w http.ResponseWriter,

 		// Return error that's not caused because the container is stopped.

 		// Return error if the container is not running and the api is >= 1.20

 		// to keep backwards compatibility.

-		version, _ := ctx.Value("api-version").(version.Version)

+		version := ctx.Version()

 		if version.GreaterThanOrEqualTo("1.20") || !isStopped {

 			return fmt.Errorf("Cannot kill container %s: %v", name, err)

 		}

@@ -392,7 +391,7 @@ func (s *Server) postContainersCreate(ctx context.Context, w http.ResponseWriter

 	if err != nil {

 		return err

 	}

-	version, _ := ctx.Value("api-version").(version.Version)

+	version := ctx.Version()

 	adjustCPUShares := version.LessThan("1.19")

 	container, warnings, err := s.daemon.ContainerCreate(name, config, hostConfig, adjustCPUShares)

@@ -9,9 +9,8 @@ import (

 	"os"

 	"strings"

-	"golang.org/x/net/context"

-

 	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/context"

 )

 // postContainersCopy is deprecated in favor of getContainersArchive.

@@ -8,17 +8,15 @@ import (

 	"strings"

 	"time"

-	"golang.org/x/net/context"

-

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api"

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/autogen/dockerversion"

+	"github.com/docker/docker/context"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/jsonmessage"

 	"github.com/docker/docker/pkg/parsers/filters"

 	"github.com/docker/docker/pkg/parsers/kernel"

-	"github.com/docker/docker/pkg/version"

 	"github.com/docker/docker/utils"

 )

@@ -33,7 +31,7 @@ func (s *Server) getVersion(ctx context.Context, w http.ResponseWriter, r *http.

 		BuildTime:  dockerversion.BUILDTIME,

 	}

-	version, _ := ctx.Value("api-version").(version.Version)

+	version := ctx.Version()

 	if version.GreaterThanOrEqualTo("1.19") {

 		v.Experimental = utils.ExperimentalBuild()

@@ -7,10 +7,9 @@ import (

 	"net/http"

 	"strconv"

-	"golang.org/x/net/context"

-

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/context"

 	"github.com/docker/docker/pkg/stdcopy"

 	"github.com/docker/docker/runconfig"

 )

@@ -8,18 +8,16 @@ import (

 	"net/http"

 	"strings"

-	"golang.org/x/net/context"

-

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api/types"

 	"github.com/docker/docker/builder"

 	"github.com/docker/docker/cliconfig"

+	"github.com/docker/docker/context"

 	"github.com/docker/docker/graph"

 	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/parsers"

 	"github.com/docker/docker/pkg/streamformatter"

 	"github.com/docker/docker/pkg/ulimit"

-	"github.com/docker/docker/pkg/version"

 	"github.com/docker/docker/runconfig"

 	"github.com/docker/docker/utils"

 )

@@ -36,7 +34,7 @@ func (s *Server) postCommit(ctx context.Context, w http.ResponseWriter, r *http.

 	cname := r.Form.Get("container")

 	pause := boolValue(r, "pause")

-	version, _ := ctx.Value("api-version").(version.Version)

+	version := ctx.Version()

 	if r.FormValue("pause") == "" && version.GreaterThanOrEqualTo("1.13") {

 		pause = true

 	}

@@ -283,7 +281,7 @@ func (s *Server) postBuild(ctx context.Context, w http.ResponseWriter, r *http.R

 	w.Header().Set("Content-Type", "application/json")

-	version, _ := ctx.Value("api-version").(version.Version)

+	version := ctx.Version()

 	if boolValue(r, "forcerm") && version.GreaterThanOrEqualTo("1.12") {

 		buildConfig.Remove = true

 	} else if r.FormValue("rm") == "" && version.GreaterThanOrEqualTo("1.12") {

@@ -4,9 +4,7 @@ import (

 	"fmt"

 	"net/http"

-	"golang.org/x/net/context"

-

-	"github.com/docker/docker/pkg/version"

+	"github.com/docker/docker/context"

 )

 // getContainersByName inspects containers configuration and serializes it as json.

@@ -18,7 +16,7 @@ func (s *Server) getContainersByName(ctx context.Context, w http.ResponseWriter,

 	var json interface{}

 	var err error

-	version, _ := ctx.Value("api-version").(version.Version)

+	version := ctx.Version()

 	switch {

 	case version.LessThan("1.20"):

@@ -12,11 +12,11 @@ import (

 	"strings"

 	"github.com/gorilla/mux"

-	"golang.org/x/net/context"

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/api"

 	"github.com/docker/docker/autogen/dockerversion"

+	"github.com/docker/docker/context"

 	"github.com/docker/docker/daemon"

 	"github.com/docker/docker/pkg/sockets"

 	"github.com/docker/docker/pkg/stringid"

@@ -261,14 +261,14 @@ func makeHTTPHandler(logging bool, localMethod string, localRoute string, handle

 		// as 'args' on the function call.

 		reqID := stringid.TruncateID(stringid.GenerateNonCryptoID())

-		api_version := version.Version(mux.Vars(r)["version"])

-		if api_version == "" {

-			api_version = api.Version

+		apiVersion := version.Version(mux.Vars(r)["version"])

+		if apiVersion == "" {

+			apiVersion = api.Version

 		}

 		ctx := context.Background()

-		ctx = context.WithValue(ctx, "docker-request-id", reqID)

-		ctx = context.WithValue(ctx, "api-version", api_version)

+		ctx = context.WithValue(ctx, context.RequestID, reqID)

+		ctx = context.WithValue(ctx, context.APIVersion, apiVersion)

 		// log the request

 		logrus.Debugf("Calling %s %s", localMethod, localRoute)

@@ -294,11 +294,11 @@ func makeHTTPHandler(logging bool, localMethod string, localRoute string, handle

 			writeCorsHeaders(w, r, corsHeaders)

 		}

-		if api_version.GreaterThan(api.Version) {

-			http.Error(w, fmt.Errorf("client is newer than server (client API version: %s, server API version: %s)", api_version, api.Version).Error(), http.StatusBadRequest)

+		if apiVersion.GreaterThan(api.Version) {

+			http.Error(w, fmt.Errorf("client is newer than server (client API version: %s, server API version: %s)", apiVersion, api.Version).Error(), http.StatusBadRequest)

 			return

 		}

-		if api_version.LessThan(api.MinVersion) {

+		if apiVersion.LessThan(api.MinVersion) {

 			http.Error(w, fmt.Errorf("client is too old, minimum supported API version is %s, please upgrade your client to a newer version", api.MinVersion).Error(), http.StatusBadRequest)

 			return

 		}

@@ -4,9 +4,8 @@ import (

 	"encoding/json"

 	"net/http"

-	"golang.org/x/net/context"

-

 	"github.com/docker/docker/api/types"

+	"github.com/docker/docker/context"

 )

 func (s *Server) getVolumesList(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

new file mode 100644

@@ -0,0 +1,64 @@

+package context

+

+import (

+	"golang.org/x/net/context"

+

+	"github.com/docker/docker/pkg/version"

+)

+

+const (

+	// RequestID is the unique ID for each http request

+	RequestID = "request-id"

+

+	// APIVersion is the client's requested API version

+	APIVersion = "api-version"

+)

+

+// Context is just our own wrapper for the golang 'Context' - mainly

+// so we can add our over version of the funcs.

+type Context struct {

+	context.Context

+}

+

+// Background creates a new Context based on golang's default one.

+func Background() Context {

+	return Context{context.Background()}

+}

+

+// WithValue will return a Context that has this new key/value pair

+// associated with it. Just uses the golang version but then wraps it.

+func WithValue(ctx Context, key, value interface{}) Context {

+	return Context{context.WithValue(ctx, key, value)}

+}

+

+// RequestID is a utility func to make it easier to get the

+// request ID associated with this Context/request.

+func (ctx Context) RequestID() string {

+	val := ctx.Value(RequestID)

+	if val == nil {

+		return ""

+	}

+

+	id, ok := val.(string)

+	if !ok {

+		// Ideally we shouldn't panic but we also should never get here

+		panic("Context RequestID isn't a string")

+	}

+	return id

+}

+

+// Version is a utility func to make it easier to get the

+// API version string associated with this Context/request.

+func (ctx Context) Version() version.Version {

+	val := ctx.Value(APIVersion)

+	if val == nil {

+		return version.Version("")

+	}

+

+	ver, ok := val.(version.Version)

+	if !ok {

+		// Ideally we shouldn't panic but we also should never get here

+		panic("Context APIVersion isn't a version.Version")

+	}

+	return ver

+}

new file mode 100644

@@ -0,0 +1,35 @@

+package context

+

+import (

+	"testing"

+

+	"github.com/docker/docker/pkg/version"

+)

+

+func TestContext(t *testing.T) {

+	ctx := Background()

+

+	// First make sure getting non-existent values doesn't break

+	if id := ctx.RequestID(); id != "" {

+		t.Fatalf("RequestID() should have been '', was: %q", id)

+	}

+

+	if ver := ctx.Version(); ver != "" {

+		t.Fatalf("Version() should have been '', was: %q", ver)

+	}

+

+	// Test basic set/get

+	ctx = WithValue(ctx, RequestID, "123")

+	if ctx.RequestID() != "123" {

+		t.Fatalf("RequestID() should have been '123'")

+	}

+

+	// Now make sure after a 2nd set we can still get both

+	ctx = WithValue(ctx, APIVersion, version.Version("x.y"))

+	if id := ctx.RequestID(); id != "123" {

+		t.Fatalf("RequestID() should have been '123', was %q", id)

+	}

+	if ver := ctx.Version(); ver != "x.y" {

+		t.Fatalf("Version() should have been 'x.y', was %q", ver)

+	}

+}