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// Copyright 2014 Google Inc. All rights reserved.
// Use of this source code is governed by the Apache 2.0
// license that can be found in the LICENSE file.
package internal
// This file has code for accessing metadata.
//
// References:
// https://cloud.google.com/compute/docs/metadata
import (
"fmt"
"io/ioutil"
"net/http"
"net/url"
)
const (
metadataHost = "metadata"
metadataPath = "/computeMetadata/v1/"
)
var (
metadataRequestHeaders = http.Header{
"Metadata-Flavor": []string{"Google"},
}
)
// TODO(dsymonds): Do we need to support default values, like Python?
func mustGetMetadata(key string) []byte {
b, err := getMetadata(key)
if err != nil {
panic(fmt.Sprintf("Metadata fetch failed for '%s': %v", key, err))
}
return b
}
func getMetadata(key string) ([]byte, error) {
// TODO(dsymonds): May need to use url.Parse to support keys with query args.
req := &http.Request{
Method: "GET",
URL: &url.URL{
Scheme: "http",
Host: metadataHost,
Path: metadataPath + key,
},
Header: metadataRequestHeaders,
Host: metadataHost,
}
resp, err := http.DefaultClient.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.StatusCode != 200 {
return nil, fmt.Errorf("metadata server returned HTTP %d", resp.StatusCode)
}
return ioutil.ReadAll(resp.Body)
}
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