# google-cloud-auth
Google Cloud Platform server application authentication library.
[](https://crates.io/crates/google-cloud-auth)
## Installation
```
[dependencies]
google-cloud-auth = <version>
```
## Quickstart
```rust
use google_cloud_auth::*;
#[tokio::main]
async fn main() -> Result<(), error::Error> {
let audience = "https://spanner.googleapis.com/";
let scopes = [
"https://www.googleapis.com/auth/cloud-platform",
"https://www.googleapis.com/auth/spanner.data",
];
let config = Config {
// audience is required only for service account jwt-auth
// https://developers.google.com/identity/protocols/oauth2/service-account#jwt-auth
audience: Some(audience),
// scopes is required only for service account Oauth2
// https://developers.google.com/identity/protocols/oauth2/service-account
scopes: Some(&scopes),
sub: None
};
let ts = create_token_source(config).await?;
let token = ts.token().await?;
println!("token is {}",token.access_token);
Ok(())
}
```
`create_token_source`looks for credentials in the following places,
preferring the first location found:
1. A JSON file whose path is specified by the
GOOGLE_APPLICATION_CREDENTIALS environment variable.
2. A JSON file in a location known to the gcloud command-line tool.
On Windows, this is %APPDATA%/gcloud/application_default_credentials.json.
On other systems, $HOME/.config/gcloud/application_default_credentials.json.
3. On Google Compute Engine, it fetches credentials from the metadata server.
## Supported Credentials
- [x] [Service Account(JWT)](https://developers.google.com/identity/protocols/oauth2/service-account#jwt-auth)
- [x] [Service Account(OAuth 2.0)](https://developers.google.com/identity/protocols/oauth2/service-account)
- [x] [Authorized User](https://cloud.google.com/docs/authentication/end-user)
- [ ] [External Account](https://cloud.google.com/anthos/clusters/docs/aws/how-to/workload-identity-gcp)
- [ ] Google Developers Console client_credentials.json
## Supported Workload Identity
https://cloud.google.com/iam/docs/workload-identity-federation
- [ ] AWS
- [ ] Azure Active Directory
- [ ] On-premises Active Directory
- [ ] Okta
- [x] Kubernetes clusters