mirror of
https://github.com/prometheus/prometheus.git
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65 lines
1.9 KiB
Go
65 lines
1.9 KiB
Go
// Copyright 2014 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package internal provides support for the cloud packages.
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//
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// Users should not import this package directly.
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package internal
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import (
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"fmt"
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"net/http"
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)
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const userAgent = "gcloud-golang/0.1"
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// Transport is an http.RoundTripper that appends Google Cloud client's
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// user-agent to the original request's user-agent header.
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type Transport struct {
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// TODO(bradfitz): delete internal.Transport. It's too wrappy for what it does.
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// Do User-Agent some other way.
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// Base is the actual http.RoundTripper
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// requests will use. It must not be nil.
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Base http.RoundTripper
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}
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// RoundTrip appends a user-agent to the existing user-agent
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// header and delegates the request to the base http.RoundTripper.
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func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
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req = cloneRequest(req)
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ua := req.Header.Get("User-Agent")
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if ua == "" {
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ua = userAgent
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} else {
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ua = fmt.Sprintf("%s %s", ua, userAgent)
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}
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req.Header.Set("User-Agent", ua)
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return t.Base.RoundTrip(req)
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}
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// cloneRequest returns a clone of the provided *http.Request.
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// The clone is a shallow copy of the struct and its Header map.
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func cloneRequest(r *http.Request) *http.Request {
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// shallow copy of the struct
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r2 := new(http.Request)
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*r2 = *r
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// deep copy of the Header
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r2.Header = make(http.Header)
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for k, s := range r.Header {
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r2.Header[k] = s
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}
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return r2
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}
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