Merge pull request #2360 from stevvooe/remove-context-type

context: remove definition of Context

blobs.go

@@ -1,13 +1,13 @@
 package distribution
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
 	"time"
 
-	"github.com/docker/distribution/context"
 	"github.com/docker/distribution/reference"
 	"github.com/opencontainers/go-digest"
 )

context/context.go

@@ -1,21 +1,16 @@
 package context
 
 import (
+	"context"
 	"sync"
 
 	"github.com/docker/distribution/uuid"
-	"golang.org/x/net/context"
 )
 
-// Context is a copy of Context from the golang.org/x/net/context package.
-type Context interface {
-	context.Context
-}
-
 // instanceContext is a context that provides only an instance id. It is
 // provided as the main background context.
 type instanceContext struct {
-	Context
+	context.Context
 	id   string    // id of context, logged as "instance.id"
 	once sync.Once // once protect generation of the id
 }
@@ -42,17 +37,10 @@ var background = &instanceContext{
 // Background returns a non-nil, empty Context. The background context
 // provides a single key, "instance.id" that is globally unique to the
 // process.
-func Background() Context {
+func Background() context.Context {
 	return background
 }
 
-// WithValue returns a copy of parent in which the value associated with key is
-// val. Use context Values only for request-scoped data that transits processes
-// and APIs, not for passing optional parameters to functions.
-func WithValue(parent Context, key, val interface{}) Context {
-	return context.WithValue(parent, key, val)
-}
-
 // stringMapContext is a simple context implementation that checks a map for a
 // key, falling back to a parent if not present.
 type stringMapContext struct {

context/http.go

@@ -1,6 +1,7 @@
 package context
 
 import (
+	"context"
 	"errors"
 	"net"
 	"net/http"
@@ -68,7 +69,7 @@ func RemoteIP(r *http.Request) string {
 // is available at "http.request". Other common attributes are available under
 // the prefix "http.request.". If a request is already present on the context,
 // this method will panic.
-func WithRequest(ctx Context, r *http.Request) Context {
+func WithRequest(ctx context.Context, r *http.Request) context.Context {
 	if ctx.Value("http.request") != nil {
 		// NOTE(stevvooe): This needs to be considered a programming error. It
 		// is unlikely that we'd want to have more than one request in
@@ -87,7 +88,7 @@ func WithRequest(ctx Context, r *http.Request) Context {
 // GetRequest returns the http request in the given context. Returns
 // ErrNoRequestContext if the context does not have an http request associated
 // with it.
-func GetRequest(ctx Context) (*http.Request, error) {
+func GetRequest(ctx context.Context) (*http.Request, error) {
 	if r, ok := ctx.Value("http.request").(*http.Request); r != nil && ok {
 		return r, nil
 	}
@@ -96,13 +97,13 @@ func GetRequest(ctx Context) (*http.Request, error) {
 
 // GetRequestID attempts to resolve the current request id, if possible. An
 // error is return if it is not available on the context.
-func GetRequestID(ctx Context) string {
+func GetRequestID(ctx context.Context) string {
 	return GetStringValue(ctx, "http.request.id")
 }
 
 // WithResponseWriter returns a new context and response writer that makes
 // interesting response statistics available within the context.
-func WithResponseWriter(ctx Context, w http.ResponseWriter) (Context, http.ResponseWriter) {
+func WithResponseWriter(ctx context.Context, w http.ResponseWriter) (context.Context, http.ResponseWriter) {
 	if closeNotifier, ok := w.(http.CloseNotifier); ok {
 		irwCN := &instrumentedResponseWriterCN{
 			instrumentedResponseWriter: instrumentedResponseWriter{
@@ -125,7 +126,7 @@ func WithResponseWriter(ctx Context, w http.ResponseWriter) (Context, http.Respo
 // GetResponseWriter returns the http.ResponseWriter from the provided
 // context. If not present, ErrNoResponseWriterContext is returned. The
 // returned instance provides instrumentation in the context.
-func GetResponseWriter(ctx Context) (http.ResponseWriter, error) {
+func GetResponseWriter(ctx context.Context) (http.ResponseWriter, error) {
 	v := ctx.Value("http.response")
 
 	rw, ok := v.(http.ResponseWriter)
@@ -145,7 +146,7 @@ var getVarsFromRequest = mux.Vars
 // example, if looking for the variable "name", it can be accessed as
 // "vars.name". Implementations that are accessing values need not know that
 // the underlying context is implemented with gorilla/mux vars.
-func WithVars(ctx Context, r *http.Request) Context {
+func WithVars(ctx context.Context, r *http.Request) context.Context {
 	return &muxVarsContext{
 		Context: ctx,
 		vars:    getVarsFromRequest(r),
@@ -155,7 +156,7 @@ func WithVars(ctx Context, r *http.Request) Context {
 // GetRequestLogger returns a logger that contains fields from the request in
 // the current context. If the request is not available in the context, no
 // fields will display. Request loggers can safely be pushed onto the context.
-func GetRequestLogger(ctx Context) Logger {
+func GetRequestLogger(ctx context.Context) Logger {
 	return GetLogger(ctx,
 		"http.request.id",
 		"http.request.method",
@@ -171,7 +172,7 @@ func GetRequestLogger(ctx Context) Logger {
 // Because the values are read at call time, pushing a logger returned from
 // this function on the context will lead to missing or invalid data. Only
 // call this at the end of a request, after the response has been written.
-func GetResponseLogger(ctx Context) Logger {
+func GetResponseLogger(ctx context.Context) Logger {
 	l := getLogrusLogger(ctx,
 		"http.response.written",
 		"http.response.status",
@@ -188,7 +189,7 @@ func GetResponseLogger(ctx Context) Logger {
 
 // httpRequestContext makes information about a request available to context.
 type httpRequestContext struct {
-	Context
+	context.Context
 
 	startedAt time.Time
 	id        string
@@ -247,7 +248,7 @@ fallback:
 }
 
 type muxVarsContext struct {
-	Context
+	context.Context
 	vars map[string]string
 }
 
@@ -282,7 +283,7 @@ type instrumentedResponseWriterCN struct {
 // implemented by the parent ResponseWriter.
 type instrumentedResponseWriter struct {
 	http.ResponseWriter
-	Context
+	context.Context
 
 	mu      sync.Mutex
 	status  int

context/logger.go

@@ -1,10 +1,11 @@
 package context
 
 import (
+	"context"
 	"fmt"
+	"runtime"
 
 	"github.com/sirupsen/logrus"
-	"runtime"
 )
 
 // Logger provides a leveled-logging interface.
@@ -40,22 +41,24 @@ type Logger interface {
 	Warnln(args ...interface{})
 }
 
+type loggerKey struct{}
+
 // WithLogger creates a new context with provided logger.
-func WithLogger(ctx Context, logger Logger) Context {
-	return WithValue(ctx, "logger", logger)
+func WithLogger(ctx context.Context, logger Logger) context.Context {
+	return context.WithValue(ctx, loggerKey{}, logger)
 }
 
 // GetLoggerWithField returns a logger instance with the specified field key
 // and value without affecting the context. Extra specified keys will be
 // resolved from the context.
-func GetLoggerWithField(ctx Context, key, value interface{}, keys ...interface{}) Logger {
+func GetLoggerWithField(ctx context.Context, key, value interface{}, keys ...interface{}) Logger {
 	return getLogrusLogger(ctx, keys...).WithField(fmt.Sprint(key), value)
 }
 
 // GetLoggerWithFields returns a logger instance with the specified fields
 // without affecting the context. Extra specified keys will be resolved from
 // the context.
-func GetLoggerWithFields(ctx Context, fields map[interface{}]interface{}, keys ...interface{}) Logger {
+func GetLoggerWithFields(ctx context.Context, fields map[interface{}]interface{}, keys ...interface{}) Logger {
 	// must convert from interface{} -> interface{} to string -> interface{} for logrus.
 	lfields := make(logrus.Fields, len(fields))
 	for key, value := range fields {
@@ -71,19 +74,19 @@ func GetLoggerWithFields(ctx Context, fields map[interface{}]interface{}, keys .
 // argument passed to GetLogger will be passed to fmt.Sprint when expanded as
 // a logging key field. If context keys are integer constants, for example,
 // its recommended that a String method is implemented.
-func GetLogger(ctx Context, keys ...interface{}) Logger {
+func GetLogger(ctx context.Context, keys ...interface{}) Logger {
 	return getLogrusLogger(ctx, keys...)
 }
 
 // GetLogrusLogger returns the logrus logger for the context. If one more keys
 // are provided, they will be resolved on the context and included in the
 // logger. Only use this function if specific logrus functionality is
 // required.
-func getLogrusLogger(ctx Context, keys ...interface{}) *logrus.Entry {
+func getLogrusLogger(ctx context.Context, keys ...interface{}) *logrus.Entry {
 	var logger *logrus.Entry
 
 	// Get a logger, if it is present.
-	loggerInterface := ctx.Value("logger")
+	loggerInterface := ctx.Value(loggerKey{})
 	if loggerInterface != nil {
 		if lgr, ok := loggerInterface.(*logrus.Entry); ok {
 			logger = lgr

context/trace.go

@@ -1,6 +1,7 @@
 package context
 
 import (
+	"context"
 	"runtime"
 	"time"
 
@@ -36,7 +37,7 @@ import (
 //
 // Notice that the function name is automatically resolved, along with the
 // package and a trace id is emitted that can be linked with parent ids.
-func WithTrace(ctx Context) (Context, func(format string, a ...interface{})) {
+func WithTrace(ctx context.Context) (context.Context, func(format string, a ...interface{})) {
 	if ctx == nil {
 		ctx = Background()
 	}
@@ -69,7 +70,7 @@ func WithTrace(ctx Context) (Context, func(format string, a ...interface{})) {
 // also provides fast lookup for the various attributes that are available on
 // the trace.
 type traced struct {
-	Context
+	context.Context
 	id     string
 	parent string
 	start  time.Time

context/trace_test.go

@@ -1,6 +1,7 @@
 package context
 
 import (
+	"context"
 	"runtime"
 	"testing"
 	"time"
@@ -35,7 +36,7 @@ func TestWithTrace(t *testing.T) {
 	ctx, done := WithTrace(Background())
 	defer done("this will be emitted at end of test")
 
-	checkContextForValues(t, ctx, append(base, valueTestCase{
+	checkContextForValues(ctx, t, append(base, valueTestCase{
 		key:      "trace.func",
 		expected: f.Name(),
 	}))
@@ -48,7 +49,7 @@ func TestWithTrace(t *testing.T) {
 		ctx, done := WithTrace(ctx)
 		defer done("this should be subordinate to the other trace")
 		time.Sleep(time.Second)
-		checkContextForValues(t, ctx, append(base, valueTestCase{
+		checkContextForValues(ctx, t, append(base, valueTestCase{
 			key:      "trace.func",
 			expected: f.Name(),
 		}, valueTestCase{
@@ -67,8 +68,7 @@ type valueTestCase struct {
 	notnilorempty bool // just check not empty/not nil
 }
 
-func checkContextForValues(t *testing.T, ctx Context, values []valueTestCase) {
-
+func checkContextForValues(ctx context.Context, t *testing.T, values []valueTestCase) {
 	for _, testcase := range values {
 		v := ctx.Value(testcase.key)
 		if testcase.notnilorempty {

context/util.go

@@ -1,13 +1,14 @@
 package context
 
 import (
+	"context"
 	"time"
 )
 
 // Since looks up key, which should be a time.Time, and returns the duration
 // since that time. If the key is not found, the value returned will be zero.
 // This is helpful when inferring metrics related to context execution times.
-func Since(ctx Context, key interface{}) time.Duration {
+func Since(ctx context.Context, key interface{}) time.Duration {
 	if startedAt, ok := ctx.Value(key).(time.Time); ok {
 		return time.Since(startedAt)
 	}
@@ -16,7 +17,7 @@ func Since(ctx Context, key interface{}) time.Duration {
 
 // GetStringValue returns a string value from the context. The empty string
 // will be returned if not found.
-func GetStringValue(ctx Context, key interface{}) (value string) {
+func GetStringValue(ctx context.Context, key interface{}) (value string) {
 	if valuev, ok := ctx.Value(key).(string); ok {
 		value = valuev
 	}

context/version.go

@@ -1,16 +1,22 @@
 package context
 
+import "context"
+
+type versionKey struct{}
+
+func (versionKey) String() string { return "version" }
+
 // WithVersion stores the application version in the context. The new context
 // gets a logger to ensure log messages are marked with the application
 // version.
-func WithVersion(ctx Context, version string) Context {
-	ctx = WithValue(ctx, "version", version)
+func WithVersion(ctx context.Context, version string) context.Context {
+	ctx = context.WithValue(ctx, versionKey{}, version)
 	// push a new logger onto the stack
-	return WithLogger(ctx, GetLogger(ctx, "version"))
+	return WithLogger(ctx, GetLogger(ctx, versionKey{}))
 }
 
 // GetVersion returns the application version from the context. An empty
 // string may returned if the version was not set on the context.
-func GetVersion(ctx Context) string {
-	return GetStringValue(ctx, "version")
+func GetVersion(ctx context.Context) string {
+	return GetStringValue(ctx, versionKey{})
 }