forked from Mirrors/oauth2
81 lines
2.4 KiB
Go
81 lines
2.4 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package externalaccount
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"golang.org/x/oauth2"
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"io"
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"io/ioutil"
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"net/http"
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"time"
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)
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// generateAccesstokenReq is used for service account impersonation
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type generateAccessTokenReq struct {
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Delegates []string `json:"delegates,omitempty"`
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Lifetime string `json:"lifetime,omitempty"`
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Scope []string `json:"scope,omitempty"`
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}
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type impersonateTokenResponse struct {
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AccessToken string `json:"accessToken"`
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ExpireTime string `json:"expireTime"`
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}
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// impersonate performs the exchange to get a temporary service account
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func (ts tokenSource) impersonate() (*oauth2.Token, error) {
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reqBody := generateAccessTokenReq{
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Lifetime: "3600s",
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Scope: ts.conf.Scopes,
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}
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b, err := json.Marshal(reqBody)
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serviceAccountImpersonationURL := ts.conf.ServiceAccountImpersonationURL
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ts.conf.ServiceAccountImpersonationURL = ""
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ts.conf.Scopes = []string{"https://www.googleapis.com/auth/cloud-platform"}
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client := oauth2.NewClient(ts.ctx, ts)
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if err != nil {
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return &oauth2.Token{}, fmt.Errorf("google: unable to marshal request: %v", err)
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}
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req, err := http.NewRequest("POST", serviceAccountImpersonationURL, bytes.NewReader(b))
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if err != nil {
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return nil, fmt.Errorf("impersonate: unable to create request: %v", err)
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}
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req = req.WithContext(ts.ctx)
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req.Header.Set("Content-Type", "application/json")
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resp, err := client.Do(req)
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if err != nil {
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return nil, fmt.Errorf("impersonate: unable to generate access token: %v", err)
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}
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defer resp.Body.Close()
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body, err := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
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if err != nil {
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return nil, fmt.Errorf("impersonate: unable to read body: %v", err)
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}
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if c := resp.StatusCode; c < 200 || c > 299 {
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return nil, fmt.Errorf("impersonate: status code %d: %s", c, body)
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}
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var accessTokenResp impersonateTokenResponse
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if err := json.Unmarshal(body, &accessTokenResp); err != nil {
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return nil, fmt.Errorf("impersonate: unable to parse response: %v", err)
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}
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expiry, err := time.Parse(time.RFC3339, accessTokenResp.ExpireTime)
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if err != nil {
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return nil, fmt.Errorf("impersonate: unable to parse expiry: %v", err)
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}
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return &oauth2.Token{
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AccessToken: accessTokenResp.AccessToken,
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Expiry: expiry,
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TokenType: "Bearer",
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}, nil
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}
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