gcs implements Google Cloud Storage object operations through the JSON API. Its direct runtime dependencies are cloud.google.com/go/compute/metadata and golang.org/x/oauth2.

go get github.com/git-pkgs/gcs

ctx := context.Background()
bucket, err := gcs.OpenBucket(ctx, "gs://my-bucket")
if err != nil {
	return err
}

_, err = bucket.Write(ctx, "packages/example.txt", strings.NewReader("content"))
if err != nil {
	return err
}

reader, err := bucket.Open(ctx, "packages/example.txt")
if err != nil {
	return err
}
defer reader.Close()

Write returns the number of bytes uploaded and sends each object as one non-resumable media upload. Retrying after a failed request starts the upload again.

Open, Exists, Delete, and Size operate on individual object names. Open and Size return ErrNotFound for a missing object; Delete accepts one. ListPrefix reads object metadata by prefix, while UsedSpace reads every object page with only the size field and takes time proportional to the object count.

OpenBucket reads Application Default Credentials from attached service accounts on GKE, GCE, and Cloud Run. It also reads a file selected by GOOGLE_APPLICATION_CREDENTIALS or local credentials created by gcloud auth application-default login.

SignedURL generates a V2 signed URL with a service-account private key when the credential file contains one. For Workload Identity and impersonated credentials, signing calls the IAM Credentials signBlob API and requires permission to sign blobs. The method returns ErrSignedURLUnsupported for the emulator and plain user credentials that do not impersonate a service account.

Set STORAGE_EMULATOR_HOST to the address of a Cloud Storage emulator. The value may include an http:// or https:// scheme.

MIT.