golang.org/x/oauth2@v0.18.0/google/downscope/tokenbroker_test.go (about)

     1  // Copyright 2021 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package downscope_test
     6  
     7  import (
     8  	"context"
     9  	"fmt"
    10  
    11  	"golang.org/x/oauth2/google"
    12  
    13  	"golang.org/x/oauth2"
    14  	"golang.org/x/oauth2/google/downscope"
    15  )
    16  
    17  func ExampleNewTokenSource() {
    18  	// This shows how to generate a downscoped token. This code would be run on the
    19  	// token broker, which holds the root token used to generate the downscoped token.
    20  	ctx := context.Background()
    21  	// Initializes an accessBoundary with one Rule which restricts the downscoped
    22  	// token to only be able to access the bucket "foo" and only grants it the
    23  	// permission "storage.objectViewer".
    24  	accessBoundary := []downscope.AccessBoundaryRule{
    25  		{
    26  			AvailableResource:    "//storage.googleapis.com/projects/_/buckets/foo",
    27  			AvailablePermissions: []string{"inRole:roles/storage.objectViewer"},
    28  		},
    29  	}
    30  
    31  	var rootSource oauth2.TokenSource
    32  	// This Source can be initialized in multiple ways; the following example uses
    33  	// Application Default Credentials.
    34  
    35  	rootSource, err := google.DefaultTokenSource(ctx, "https://www.googleapis.com/auth/cloud-platform")
    36  
    37  	dts, err := downscope.NewTokenSource(ctx, downscope.DownscopingConfig{RootSource: rootSource, Rules: accessBoundary})
    38  	if err != nil {
    39  		fmt.Printf("failed to generate downscoped token source: %v", err)
    40  		return
    41  	}
    42  
    43  	tok, err := dts.Token()
    44  	if err != nil {
    45  		fmt.Printf("failed to generate token: %v", err)
    46  		return
    47  	}
    48  	_ = tok
    49  	// You can now pass tok to a token consumer however you wish, such as exposing
    50  	// a REST API and sending it over HTTP.
    51  
    52  	// You can instead use the token held in dts to make
    53  	// Google Cloud Storage calls, as follows:
    54  
    55  	// storageClient, err := storage.NewClient(ctx, option.WithTokenSource(dts))
    56  
    57  }