Documentation
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Overview ¶
Package externalaccount provides support for creating workload identity federation and workforce identity federation token providers that can be used to access Google Cloud resources from external identity providers.
Workload Identity Federation ¶
Using workload identity federation, your application can access Google Cloud resources from Amazon Web Services (AWS), Microsoft Azure or any identity provider that supports OpenID Connect (OIDC) or SAML 2.0. Traditionally, applications running outside Google Cloud have used service account keys to access Google Cloud resources. Using identity federation, you can allow your workload to impersonate a service account. This lets you access Google Cloud resources directly, eliminating the maintenance and security burden associated with service account keys.
Follow the detailed instructions on how to configure Workload Identity Federation in various platforms:
- Amazon Web Services (AWS): https://cloud.google.com/iam/docs/workload-identity-federation-with-other-clouds#aws - Microsoft Azure: https://cloud.google.com/iam/docs/workload-identity-federation-with-other-clouds#azure - OIDC identity provider: https://cloud.google.com/iam/docs/workload-identity-federation-with-other-providers#oidc - SAML 2.0 identity provider: https://cloud.google.com/iam/docs/workload-identity-federation-with-other-providers#saml
For OIDC and SAML providers, the library can retrieve tokens in fours ways: from a local file location (file-sourced credentials), from a server (URL-sourced credentials), from a local executable (executable-sourced credentials), or from a user defined function that returns an OIDC or SAML token. For file-sourced credentials, a background process needs to be continuously refreshing the file location with a new OIDC/SAML token prior to expiration. For tokens with one hour lifetimes, the token needs to be updated in the file every hour. The token can be stored directly as plain text or in JSON format. For URL-sourced credentials, a local server needs to host a GET endpoint to return the OIDC/SAML token. The response can be in plain text or JSON. Additional required request headers can also be specified. For executable-sourced credentials, an application needs to be available to output the OIDC/SAML token and other information in a JSON format. For more information on how these work (and how to implement executable-sourced credentials), please check out: https://cloud.google.com/iam/docs/workload-identity-federation-with-other-providers#create_a_credential_configuration
To use a custom function to supply the token, define a struct that implements the SubjectTokenProvider interface for OIDC/SAML providers, or one that implements AwsSecurityCredentialsProvider for AWS providers. This can then be used when building a Options.The cloud.google.com/go/auth.Credentials created from the options using NewCredentials can then be used to access Google Cloud resources. For instance, you can create a new client from the cloud.google.com/go/storage package and pass in option.WithTokenProvider(yourTokenProvider))
Workforce Identity Federation ¶
Workforce identity federation lets you use an external identity provider (IdP) to authenticate and authorize a workforce—a group of users, such as employees, partners, and contractors—using IAM, so that the users can access Google Cloud services. Workforce identity federation extends Google Cloud's identity capabilities to support syncless, attribute-based single sign on.
With workforce identity federation, your workforce can access Google Cloud resources using an external identity provider (IdP) that supports OpenID Connect (OIDC) or SAML 2.0 such as Azure Active Directory (Azure AD), Active Directory Federation Services (AD FS), Okta, and others.
Follow the detailed instructions on how to configure Workload Identity Federation in various platforms:
For workforce identity federation, the library can retrieve tokens in three ways: from a local file location (file-sourced credentials), from a server (URL-sourced credentials), or from a local executable (executable-sourced credentials). For file-sourced credentials, a background process needs to be continuously refreshing the file location with a new OIDC/SAML token prior to expiration. For tokens with one hour lifetimes, the token needs to be updated in the file every hour. The token can be stored directly as plain text or in JSON format. For URL-sourced credentials, a local server needs to host a GET endpoint to return the OIDC/SAML token. The response can be in plain text or JSON. Additional required request headers can also be specified. For executable-sourced credentials, an application needs to be available to output the OIDC/SAML token and other information in a JSON format. For more information on how these work (and how to implement executable-sourced credentials), please check out: https://cloud.google.com/iam/docs/workforce-obtaining-short-lived-credentials#generate_a_configuration_file_for_non-interactive_sign-in
Security considerations ¶
Note that this library does not perform any validation on the token_url, token_info_url, or service_account_impersonation_url fields of the credential configuration. It is not recommended to use a credential configuration that you did not generate with the gcloud CLI unless you verify that the URL fields point to a googleapis.com domain.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func NewCredentials ¶
func NewCredentials(opts *Options) (*auth.Credentials, error)
NewCredentials returns a cloud.google.com/go/auth.Credentials configured with the provided options.
Types ¶
type AwsSecurityCredentials ¶
type AwsSecurityCredentials struct {
// AccessKeyId is the AWS Access Key ID - Required.
AccessKeyID string `json:"AccessKeyID"`
// SecretAccessKey is the AWS Secret Access Key - Required.
SecretAccessKey string `json:"SecretAccessKey"`
// SessionToken is the AWS Session token. This should be provided for
// temporary AWS security credentials - Optional.
SessionToken string `json:"Token"`
}
AwsSecurityCredentials models AWS security credentials.
type AwsSecurityCredentialsProvider ¶
type AwsSecurityCredentialsProvider interface {
// AwsRegion should return the AWS region or an error.
AwsRegion(ctx context.Context, opts *RequestOptions) (string, error)
// GetAwsSecurityCredentials should return a valid set of
// AwsSecurityCredentials or an error. The external account token provider
// does not cache the returned security credentials, so caching logic should
// be implemented in the provider to prevent multiple requests for the
// same security credentials.
AwsSecurityCredentials(ctx context.Context, opts *RequestOptions) (*AwsSecurityCredentials, error)
}
AwsSecurityCredentialsProvider can be used to supply AwsSecurityCredentials and an AWS Region to exchange for a GCP access token.
type CredentialSource ¶
type CredentialSource struct {
// File is the location for file sourced credentials.
// One field amongst File, URL, Executable, or EnvironmentID should be
// provided, depending on the kind of credential in question.
File string
// Url is the URL to call for URL sourced credentials.
// One field amongst File, URL, Executable, or EnvironmentID should be
// provided, depending on the kind of credential in question.
URL string
// Executable is the configuration object for executable sourced credentials.
// One field amongst File, URL, Executable, or EnvironmentID should be
// provided, depending on the kind of credential in question.
Executable *ExecutableConfig
// EnvironmentID is the EnvironmentID used for AWS sourced credentials.
// This should start with "AWS".
// One field amongst File, URL, Executable, or EnvironmentID should be provided, depending on the kind of credential in question.
EnvironmentID string
// Headers are the headers to attach to the request for URL sourced
// credentials.
Headers map[string]string
// RegionURL is the metadata URL to retrieve the region from for EC2 AWS
// credentials.
RegionURL string
// RegionalCredVerificationURL is the AWS regional credential verification
// URL, will default to `https://sts.{region}.amazonaws.com?Action=GetCallerIdentity&Version=2011-06-15`
// if not provided.
RegionalCredVerificationURL string
// IMDSv2SessionTokenURL is the URL to retrieve the session token when using
// IMDSv2 in AWS.
IMDSv2SessionTokenURL string
// Format is the format type for the subject token. Used for File and URL
// sourced credentials.
Format *Format
}
CredentialSource stores the information necessary to retrieve the credentials for the STS exchange.
type ExecutableConfig ¶
type ExecutableConfig struct {
// Command is the the full command to run to retrieve the subject token.
// This can include arguments. Must be an absolute path for the program. Required.
Command string
// TimeoutMillis is the timeout duration, in milliseconds. Defaults to 30000 milliseconds when not provided. Optional.
TimeoutMillis int
// OutputFile is the absolute path to the output file where the executable will cache the response.
// If specified the auth libraries will first check this location before running the executable. Optional.
OutputFile string
}
ExecutableConfig contains information needed for executable sourced credentials.
type Format ¶
type Format struct {
// Type should be either "text" or "json". This determines whether the file
// or URL sourced credentials expect a simple text subject token or if the
// subject token will be contained in a JSON object. When not provided
// "text" type is assumed.
Type string
// SubjectTokenFieldName is only required for JSON format. This is the field
// name that the credentials will check for the subject token in the file or
// URL response. This would be "access_token" for azure.
SubjectTokenFieldName string
}
Format contains information needed to retrieve a subject token for URL or File sourced credentials.
type Options ¶
type Options struct {
// Audience is the Secure Token Service (STS) audience which contains the
// resource name for the workload identity pool or the workforce pool and
// the provider identifier in that pool. Required.
Audience string
// SubjectTokenType is the STS token type based on the Oauth2.0 token
// exchange spec. Expected values include:
// - “urn:ietf:params:oauth:token-type:jwt”
// - “urn:ietf:params:oauth:token-type:id-token”
// - “urn:ietf:params:oauth:token-type:saml2”
// - “urn:ietf:params:aws:token-type:aws4_request”
// Required.
SubjectTokenType string
// TokenURL is the STS token exchange endpoint. If not provided, will
// default to https://sts.UNIVERSE_DOMAIN/v1/token, with UNIVERSE_DOMAIN set
// to the default service domain googleapis.com unless UniverseDomain is
// set. Optional.
TokenURL string
// TokenInfoURL is the token_info endpoint used to retrieve the account
// related information (user attributes like account identifier, eg. email,
// username, uid, etc). This is needed for gCloud session account
// identification. Optional.
TokenInfoURL string
// ServiceAccountImpersonationURL is the URL for the service account
// impersonation request. This is only required for workload identity pools
// when APIs to be accessed have not integrated with UberMint.
ServiceAccountImpersonationURL string
// ServiceAccountImpersonationLifetimeSeconds is the number of seconds the
// service account impersonation token will be valid for.
ServiceAccountImpersonationLifetimeSeconds int
// ClientSecret is currently only required if token_info endpoint also
// needs to be called with the generated GCP access token. When provided,
// STS will be called with additional basic authentication using client_id
// as username and client_secret as password. Optional.
ClientSecret string
// ClientID is only required in conjunction with ClientSecret, as described
// above. Optional.
ClientID string
// CredentialSource contains the necessary information to retrieve the token
// itself, as well as some environmental information. Optional.
CredentialSource *CredentialSource
// QuotaProjectID is injected by gCloud. If the value is non-empty, the Auth
// libraries will set the x-goog-user-project which overrides the project
// associated with the credentials. Optional.
QuotaProjectID string
// Scopes contains the desired scopes for the returned access token.
// Optional.
Scopes []string
// WorkforcePoolUserProject should be set when it is a workforce pool and
// not a workload identity pool. The underlying principal must still have
// serviceusage.services.use IAM permission to use the project for
// billing/quota. Optional.
WorkforcePoolUserProject string
// UniverseDomain is the default service domain for a given Cloud universe.
// This value will be used in the default STS token URL. The default value
// is "googleapis.com". It will not be used if TokenURL is set. Optional.
UniverseDomain string
// SubjectTokenProvider is an optional token provider for OIDC/SAML
// credentials. One of SubjectTokenProvider, AWSSecurityCredentialProvider
// or CredentialSource must be provided. Optional.
SubjectTokenProvider SubjectTokenProvider
// AwsSecurityCredentialsProvider is an AWS Security Credential provider
// for AWS credentials. One of SubjectTokenProvider,
// AWSSecurityCredentialProvider or CredentialSource must be provided. Optional.
AwsSecurityCredentialsProvider AwsSecurityCredentialsProvider
// Client configures the underlying client used to make network requests
// when fetching tokens. Optional.
Client *http.Client
}
Options for creating a cloud.google.com/go/auth.Credentials.
type RequestOptions ¶
type RequestOptions struct {
// Audience is the requested audience for the external account credential.
Audience string
// Subject token type is the requested subject token type for the external
// account credential. Expected values include:
// “urn:ietf:params:oauth:token-type:jwt”
// “urn:ietf:params:oauth:token-type:id-token”
// “urn:ietf:params:oauth:token-type:saml2”
// “urn:ietf:params:aws:token-type:aws4_request”
SubjectTokenType string
}
RequestOptions contains information about the requested subject token or AWS security credentials from the Google external account credential.
type SubjectTokenProvider ¶
type SubjectTokenProvider interface {
// SubjectToken should return a valid subject token or an error.
// The external account token provider does not cache the returned subject
// token, so caching logic should be implemented in the provider to prevent
// multiple requests for the same subject token.
SubjectToken(ctx context.Context, opts *RequestOptions) (string, error)
}
SubjectTokenProvider can be used to supply a subject token to exchange for a GCP access token.
Source Files