ecs_provider.go

Documentation: go.mongodb.org/mongo-driver/internal/credproviders

     1  // Copyright (C) MongoDB, Inc. 2023-present.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License"); you may
     4  // not use this file except in compliance with the License. You may obtain
     5  // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
     6  
     7  package credproviders
     8  
     9  import (
    10  	"context"
    11  	"encoding/json"
    12  	"errors"
    13  	"fmt"
    14  	"net/http"
    15  	"time"
    16  
    17  	"go.mongodb.org/mongo-driver/internal/aws/credentials"
    18  )
    19  
    20  const (
    21  	// ecsProviderName provides a name of ECS provider
    22  	ecsProviderName = "ECSProvider"
    23  
    24  	awsRelativeURI = "http://169.254.170.2/"
    25  )
    26  
    27  // An ECSProvider retrieves credentials from ECS metadata.
    28  type ECSProvider struct {
    29  	AwsContainerCredentialsRelativeURIEnv EnvVar
    30  
    31  	httpClient *http.Client
    32  	expiration time.Time
    33  
    34  	// expiryWindow will allow the credentials to trigger refreshing prior to the credentials actually expiring.
    35  	// This is beneficial so expiring credentials do not cause request to fail unexpectedly due to exceptions.
    36  	//
    37  	// So a ExpiryWindow of 10s would cause calls to IsExpired() to return true
    38  	// 10 seconds before the credentials are actually expired.
    39  	expiryWindow time.Duration
    40  }
    41  
    42  // NewECSProvider returns a pointer to an ECS credential provider.
    43  func NewECSProvider(httpClient *http.Client, expiryWindow time.Duration) *ECSProvider {
    44  	return &ECSProvider{
    45  		// AwsContainerCredentialsRelativeURIEnv is the environment variable for AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
    46  		AwsContainerCredentialsRelativeURIEnv: EnvVar("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI"),
    47  		httpClient:                            httpClient,
    48  		expiryWindow:                          expiryWindow,
    49  	}
    50  }
    51  
    52  // RetrieveWithContext retrieves the keys from the AWS service.
    53  func (e *ECSProvider) RetrieveWithContext(ctx context.Context) (credentials.Value, error) {
    54  	const defaultHTTPTimeout = 10 * time.Second
    55  
    56  	v := credentials.Value{ProviderName: ecsProviderName}
    57  
    58  	relativeEcsURI := e.AwsContainerCredentialsRelativeURIEnv.Get()
    59  	if len(relativeEcsURI) == 0 {
    60  		return v, errors.New("AWS_CONTAINER_CREDENTIALS_RELATIVE_URI is missing")
    61  	}
    62  	fullURI := awsRelativeURI + relativeEcsURI
    63  
    64  	req, err := http.NewRequest(http.MethodGet, fullURI, nil)
    65  	if err != nil {
    66  		return v, err
    67  	}
    68  	req.Header.Set("Accept", "application/json")
    69  
    70  	ctx, cancel := context.WithTimeout(ctx, defaultHTTPTimeout)
    71  	defer cancel()
    72  	resp, err := e.httpClient.Do(req.WithContext(ctx))
    73  	if err != nil {
    74  		return v, err
    75  	}
    76  	defer resp.Body.Close()
    77  	if resp.StatusCode != http.StatusOK {
    78  		return v, fmt.Errorf("response failure: %s", resp.Status)
    79  	}
    80  
    81  	var ecsResp struct {
    82  		AccessKeyID     string    `json:"AccessKeyId"`
    83  		SecretAccessKey string    `json:"SecretAccessKey"`
    84  		Token           string    `json:"Token"`
    85  		Expiration      time.Time `json:"Expiration"`
    86  	}
    87  
    88  	err = json.NewDecoder(resp.Body).Decode(&ecsResp)
    89  	if err != nil {
    90  		return v, err
    91  	}
    92  
    93  	v.AccessKeyID = ecsResp.AccessKeyID
    94  	v.SecretAccessKey = ecsResp.SecretAccessKey
    95  	v.SessionToken = ecsResp.Token
    96  	if !v.HasKeys() {
    97  		return v, errors.New("failed to retrieve ECS keys")
    98  	}
    99  	e.expiration = ecsResp.Expiration.Add(-e.expiryWindow)
   100  
   101  	return v, nil
   102  }
   103  
   104  // Retrieve retrieves the keys from the AWS service.
   105  func (e *ECSProvider) Retrieve() (credentials.Value, error) {
   106  	return e.RetrieveWithContext(context.Background())
   107  }
   108  
   109  // IsExpired returns true if the credentials are expired.
   110  func (e *ECSProvider) IsExpired() bool {
   111  	return e.expiration.Before(time.Now())
   112  }
   113
View as plain text