auth.go•4.57 kB
// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0
package googlecloud
import (
"context"
"encoding/json"
"fmt"
"os"
"golang.org/x/oauth2/google"
)
// GcpPrincipal represents the current GCP principal information
type GcpPrincipal struct {
ProjectID string `json:"project_id,omitempty"`
ServiceAccountEmail string `json:"service_account_email,omitempty"`
}
// GcpAuthConfig represents authentication configuration for GCP
type GcpAuthConfig struct {
ProjectID string
Credentials *google.Credentials
}
// CredentialsFromEnvironment allows Google Cloud credentials to be passed in "raw" as an environment
// variable. This is helpful in environments where the developer has limited
// ability to configure their compute environment, but does have the ability to
// set environment variables.
//
// This is different from the GOOGLE_APPLICATION_CREDENTIALS used by ADC, which
// represents a path to a credential file on disk. In *most* cases, even for
// 3rd party cloud providers, developers *should* attempt to use ADC, which
// searches for credential files in standard locations, before using this
// method.
//
// See also: https://cloud.google.com/docs/authentication/provide-credentials-adc
func CredentialsFromEnvironment() (*GcpAuthConfig, error) {
ctx := context.Background()
config := &GcpAuthConfig{}
if credsJSON := os.Getenv("GCLOUD_SERVICE_ACCOUNT_CREDS"); credsJSON != "" {
var serviceAccountCreds map[string]interface{}
if err := json.Unmarshal([]byte(credsJSON), &serviceAccountCreds); err != nil {
return nil, fmt.Errorf("failed to parse GCLOUD_SERVICE_ACCOUNT_CREDS: %w", err)
}
creds, err := google.CredentialsFromJSON(ctx, []byte(credsJSON))
if err != nil {
return nil, fmt.Errorf("failed to create credentials from service account: %w", err)
}
config.Credentials = creds
if projectID, ok := serviceAccountCreds["project_id"].(string); ok && projectID != "" {
config.ProjectID = projectID
}
} else {
creds, err := google.FindDefaultCredentials(ctx)
if err != nil {
return nil, fmt.Errorf("failed to find default credentials: %w", err)
}
config.Credentials = creds
config.ProjectID = creds.ProjectID
}
if config.ProjectID == "" && config.Credentials != nil {
if config.Credentials.ProjectID != "" {
config.ProjectID = config.Credentials.ProjectID
}
}
return config, nil
}
// ResolveCurrentPrincipal resolves the currently configured principal, either from the Genkit specific
// GCLOUD_SERVICE_ACCOUNT_CREDS environment variable, or from ADC.
//
// Since the Google Cloud Telemetry Exporter will discover credentials on its
// own, we don't immediately have access to the current principal. This method
// can be handy to get access to the current credential for logging debugging
// information or other purposes.
func ResolveCurrentPrincipal() (*GcpPrincipal, error) {
ctx := context.Background()
principal := &GcpPrincipal{}
envConfig, err := CredentialsFromEnvironment()
if err != nil {
adcCreds, adcErr := google.FindDefaultCredentials(ctx)
if adcErr != nil {
return principal, fmt.Errorf("could not resolve credentials from environment or ADC: %w", err)
}
principal.ProjectID = adcCreds.ProjectID
if email := extractServiceAccountEmail(adcCreds); email != "" {
principal.ServiceAccountEmail = email
}
return principal, nil
}
principal.ProjectID = envConfig.ProjectID
if email := extractServiceAccountEmail(envConfig.Credentials); email != "" {
principal.ServiceAccountEmail = email
}
return principal, nil
}
// extractServiceAccountEmail extracts the service account email from Google credentials
func extractServiceAccountEmail(creds *google.Credentials) string {
if creds == nil {
return ""
}
if creds.JSON != nil {
var serviceAccount map[string]interface{}
if err := json.Unmarshal(creds.JSON, &serviceAccount); err == nil {
if email, ok := serviceAccount["client_email"].(string); ok {
return email
}
}
}
return ""
}