Replace uuid dependency with internal library

Signed-off-by: Stephen J Day <stephen.day@docker.com>

context/context.go

@@ -1,7 +1,7 @@
 package context
 
 import (
-	"code.google.com/p/go-uuid/uuid"
+	"github.com/docker/distribution/uuid"
 	"golang.org/x/net/context"
 )
 
@@ -27,7 +27,7 @@ func (ic *instanceContext) Value(key interface{}) interface{} {
 
 var background = &instanceContext{
 	Context: context.Background(),
-	id:      uuid.New(),
+	id:      uuid.Generate().String(),
 }
 
 // Background returns a non-nil, empty Context. The background context

context/http.go

@@ -8,8 +8,8 @@ import (
 	"sync"
 	"time"
 
-	"code.google.com/p/go-uuid/uuid"
 	log "github.com/Sirupsen/logrus"
+	"github.com/docker/distribution/uuid"
 	"github.com/gorilla/mux"
 )
 
@@ -79,7 +79,7 @@ func WithRequest(ctx Context, r *http.Request) Context {
 	return &httpRequestContext{
 		Context:   ctx,
 		startedAt: time.Now(),
-		id:        uuid.New(), // assign the request a unique.
+		id:        uuid.Generate().String(),
 		r:         r,
 	}
 }

context/logger.go

@@ -3,6 +3,8 @@ package context
 import (
 	"fmt"
 
+	"github.com/docker/distribution/uuid"
+
 	"github.com/Sirupsen/logrus"
 )
 
@@ -99,3 +101,8 @@ func getLogrusLogger(ctx Context, keys ...interface{}) *logrus.Entry {
 
 	return logger.WithFields(fields)
 }
+
+func init() {
+	// inject a logger into the uuid library.
+	uuid.Loggerf = GetLogger(Background()).Warnf
+}

context/trace.go

@@ -4,7 +4,7 @@ import (
 	"runtime"
 	"time"
 
-	"code.google.com/p/go-uuid/uuid"
+	"github.com/docker/distribution/uuid"
 )
 
 // WithTrace allocates a traced timing span in a new context. This allows a
@@ -45,7 +45,7 @@ func WithTrace(ctx Context) (Context, func(format string, a ...interface{})) {
 	f := runtime.FuncForPC(pc)
 	ctx = &traced{
 		Context: ctx,
-		id:      uuid.New(),
+		id:      uuid.Generate().String(),
 		start:   time.Now(),
 		parent:  GetStringValue(ctx, "trace.id"),
 		fnname:  f.Name(),