github.com/google/cloudprober@v0.11.3/common/oauth/bearer.go (about)

     1  // Copyright 2019 The Cloudprober Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package oauth
    16  
    17  import (
    18  	"fmt"
    19  	"os/exec"
    20  	"strings"
    21  	"sync"
    22  	"time"
    23  
    24  	"github.com/google/cloudprober/common/file"
    25  	configpb "github.com/google/cloudprober/common/oauth/proto"
    26  	"github.com/google/cloudprober/logger"
    27  	"golang.org/x/oauth2"
    28  	"golang.org/x/oauth2/google"
    29  )
    30  
    31  type bearerTokenSource struct {
    32  	c                   *configpb.BearerToken
    33  	getTokenFromBackend func(*configpb.BearerToken) (string, error)
    34  	cache               string
    35  	mu                  sync.RWMutex
    36  	l                   *logger.Logger
    37  }
    38  
    39  var getTokenFromFile = func(c *configpb.BearerToken) (string, error) {
    40  	b, err := file.ReadFile(c.GetFile())
    41  	if err != nil {
    42  		return "", err
    43  	}
    44  	return string(b), nil
    45  }
    46  
    47  var getTokenFromCmd = func(c *configpb.BearerToken) (string, error) {
    48  	var cmd *exec.Cmd
    49  
    50  	cmdParts := strings.Split(c.GetCmd(), " ")
    51  	cmd = exec.Command(cmdParts[0], cmdParts[1:len(cmdParts)]...)
    52  
    53  	out, err := cmd.Output()
    54  	if err != nil {
    55  		return "", fmt.Errorf("failed to execute command: %v", cmd)
    56  	}
    57  	return string(out), nil
    58  }
    59  
    60  var getTokenFromGCEMetadata = func(c *configpb.BearerToken) (string, error) {
    61  	ts := google.ComputeTokenSource(c.GetGceServiceAccount())
    62  	tok, err := ts.Token()
    63  	return tok.AccessToken, err
    64  }
    65  
    66  func newBearerTokenSource(c *configpb.BearerToken, l *logger.Logger) (oauth2.TokenSource, error) {
    67  	ts := &bearerTokenSource{
    68  		c: c,
    69  		l: l,
    70  	}
    71  
    72  	switch ts.c.Source.(type) {
    73  	case *configpb.BearerToken_File:
    74  		ts.getTokenFromBackend = getTokenFromFile
    75  
    76  	case *configpb.BearerToken_Cmd:
    77  		ts.getTokenFromBackend = getTokenFromCmd
    78  
    79  	case *configpb.BearerToken_GceServiceAccount:
    80  		ts.getTokenFromBackend = getTokenFromGCEMetadata
    81  
    82  	default:
    83  		ts.getTokenFromBackend = getTokenFromGCEMetadata
    84  	}
    85  
    86  	tok, err := ts.getTokenFromBackend(c)
    87  	if err != nil {
    88  		return nil, err
    89  	}
    90  	ts.cache = tok
    91  
    92  	if ts.c.GetRefreshIntervalSec() == 0 {
    93  		return ts, nil
    94  	}
    95  
    96  	go func() {
    97  		interval := time.Duration(ts.c.GetRefreshIntervalSec()) * time.Second
    98  
    99  		for range time.Tick(interval) {
   100  			tok, err := ts.getTokenFromBackend(ts.c)
   101  
   102  			if err != nil {
   103  				ts.l.Warningf("oauth.bearerTokenSource: %s", err)
   104  				continue
   105  			}
   106  
   107  			ts.mu.Lock()
   108  			ts.cache = tok
   109  			ts.mu.Unlock()
   110  		}
   111  	}()
   112  
   113  	return ts, nil
   114  }
   115  
   116  func (ts *bearerTokenSource) Token() (*oauth2.Token, error) {
   117  	ts.mu.RLock()
   118  	defer ts.mu.RUnlock()
   119  
   120  	if ts.c.GetRefreshIntervalSec() == 0 {
   121  		tok, err := ts.getTokenFromBackend(ts.c)
   122  
   123  		if err != nil {
   124  			if ts.cache == "" {
   125  				return nil, err
   126  			}
   127  
   128  			ts.l.Errorf("oauth.bearerTokenSource: failed to get token: %v, using cache", err)
   129  			return &oauth2.Token{AccessToken: ts.cache}, nil
   130  		}
   131  
   132  		return &oauth2.Token{AccessToken: tok}, nil
   133  	}
   134  
   135  	return &oauth2.Token{AccessToken: ts.cache}, nil
   136  }