forked from TrueCloudLab/distribution
128 lines
3.6 KiB
Go
128 lines
3.6 KiB
Go
// Copyright 2014 Google Inc. All Rights Reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// Package internal provides support for the cloud packages.
|
|
//
|
|
// Users should not import this package directly.
|
|
package internal
|
|
|
|
import (
|
|
"fmt"
|
|
"net/http"
|
|
"sync"
|
|
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
type contextKey struct{}
|
|
|
|
func WithContext(parent context.Context, projID string, c *http.Client) context.Context {
|
|
if c == nil {
|
|
panic("nil *http.Client passed to WithContext")
|
|
}
|
|
if projID == "" {
|
|
panic("empty project ID passed to WithContext")
|
|
}
|
|
return context.WithValue(parent, contextKey{}, &cloudContext{
|
|
ProjectID: projID,
|
|
HTTPClient: c,
|
|
})
|
|
}
|
|
|
|
const userAgent = "gcloud-golang/0.1"
|
|
|
|
type cloudContext struct {
|
|
ProjectID string
|
|
HTTPClient *http.Client
|
|
|
|
mu sync.Mutex // guards svc
|
|
svc map[string]interface{} // e.g. "storage" => *rawStorage.Service
|
|
}
|
|
|
|
// Service returns the result of the fill function if it's never been
|
|
// called before for the given name (which is assumed to be an API
|
|
// service name, like "datastore"). If it has already been cached, the fill
|
|
// func is not run.
|
|
// It's safe for concurrent use by multiple goroutines.
|
|
func Service(ctx context.Context, name string, fill func(*http.Client) interface{}) interface{} {
|
|
return cc(ctx).service(name, fill)
|
|
}
|
|
|
|
func (c *cloudContext) service(name string, fill func(*http.Client) interface{}) interface{} {
|
|
c.mu.Lock()
|
|
defer c.mu.Unlock()
|
|
|
|
if c.svc == nil {
|
|
c.svc = make(map[string]interface{})
|
|
} else if v, ok := c.svc[name]; ok {
|
|
return v
|
|
}
|
|
v := fill(c.HTTPClient)
|
|
c.svc[name] = v
|
|
return v
|
|
}
|
|
|
|
// Transport is an http.RoundTripper that appends
|
|
// Google Cloud client's user-agent to the original
|
|
// request's user-agent header.
|
|
type Transport struct {
|
|
// Base represents the actual http.RoundTripper
|
|
// the requests will be delegated to.
|
|
Base http.RoundTripper
|
|
}
|
|
|
|
// RoundTrip appends a user-agent to the existing user-agent
|
|
// header and delegates the request to the base http.RoundTripper.
|
|
func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
|
|
req = cloneRequest(req)
|
|
ua := req.Header.Get("User-Agent")
|
|
if ua == "" {
|
|
ua = userAgent
|
|
} else {
|
|
ua = fmt.Sprintf("%s %s", ua, userAgent)
|
|
}
|
|
req.Header.Set("User-Agent", ua)
|
|
return t.Base.RoundTrip(req)
|
|
}
|
|
|
|
// cloneRequest returns a clone of the provided *http.Request.
|
|
// The clone is a shallow copy of the struct and its Header map.
|
|
func cloneRequest(r *http.Request) *http.Request {
|
|
// shallow copy of the struct
|
|
r2 := new(http.Request)
|
|
*r2 = *r
|
|
// deep copy of the Header
|
|
r2.Header = make(http.Header)
|
|
for k, s := range r.Header {
|
|
r2.Header[k] = s
|
|
}
|
|
return r2
|
|
}
|
|
|
|
func ProjID(ctx context.Context) string {
|
|
return cc(ctx).ProjectID
|
|
}
|
|
|
|
func HTTPClient(ctx context.Context) *http.Client {
|
|
return cc(ctx).HTTPClient
|
|
}
|
|
|
|
// cc returns the internal *cloudContext (cc) state for a context.Context.
|
|
// It panics if the user did it wrong.
|
|
func cc(ctx context.Context) *cloudContext {
|
|
if c, ok := ctx.Value(contextKey{}).(*cloudContext); ok {
|
|
return c
|
|
}
|
|
panic("invalid context.Context type; it should be created with cloud.NewContext")
|
|
}
|