Move context stuff to its own package

Signed-off-by: Doug Davis <dug@us.ibm.com>

api/server/auth.go

@@ -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 {

api/server/container.go

@@ -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)

api/server/copy.go

@@ -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.

api/server/daemon.go

@@ -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()

api/server/exec.go

@@ -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"
 )

api/server/image.go

@@ -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") {

api/server/inspect.go

@@ -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"):

api/server/server.go

@@ -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
 		}

api/server/volume.go

@@ -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 {

context/context.go

@@ -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
+}

context/context_test.go

@@ -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)
+	}
+}