70 lines
2.3 KiB
Go
70 lines
2.3 KiB
Go
// Copyright 2021 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package detect is used find information from the environment.
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package detect
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import (
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"context"
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"errors"
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"fmt"
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"os"
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"golang.org/x/oauth2/google"
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"google.golang.org/api/option"
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"google.golang.org/api/transport"
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)
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const (
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// ProjectIDSentinel is the value that users should pass for the project ID
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// to enable detection.
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ProjectIDSentinel = "*detect-project-id*"
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envProjectID = "GOOGLE_CLOUD_PROJECT"
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)
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var (
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adcLookupFunc func(context.Context, ...option.ClientOption) (*google.Credentials, error) = transport.Creds
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envLookupFunc func(string) string = os.Getenv
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)
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// ProjectID tries to detect the project ID from the environment if the sentinel
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// value, "*detect-project-id*", is sent. It looks in the following order:
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// 1. GOOGLE_CLOUD_PROJECT envvar
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// 2. ADC creds.ProjectID
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// 3. A static value if the environment is emulated.
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func ProjectID(ctx context.Context, projectID, emulatorEnvVar string, opts ...option.ClientOption) (string, error) {
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if projectID != ProjectIDSentinel {
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return projectID, nil
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}
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// 1. Try a well known environment variable
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if id := envLookupFunc(envProjectID); id != "" {
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return id, nil
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}
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// 2. Try ADC
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creds, err := adcLookupFunc(ctx, opts...)
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if err != nil {
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return "", fmt.Errorf("fetching creds: %v", err)
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}
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// 3. If ADC does not work, and the environment is emulated, return a const value.
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if creds.ProjectID == "" && emulatorEnvVar != "" && envLookupFunc(emulatorEnvVar) != "" {
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return "emulated-project", nil
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}
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// 4. If 1-3 don't work, error out
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if creds.ProjectID == "" {
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return "", errors.New("unable to detect projectID, please refer to docs for DetectProjectID")
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}
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// Success from ADC
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return creds.ProjectID, nil
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}
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