/** Guarded by this. */
  private OAuthSession session;

  public SlackClient(SlackApi slackApi) {
    this.slackApi = slackApi;
  }

  /** Shows a browser URL to authorize this app to act as this user. */
  public void requestOauthSession(String scopes, String team) throws Exception {
    if (sessionFactory == null) {
      sessionFactory = new OAuthSessionFactory(slackApi);

OPA is a lightweight general-purpose policy engine that can be co-located with MinIO server, in this document we talk about how to use OPA HTTP API to authorize requests. It can be used with any type of credentials (STS based like OpenID or LDAP, regular IAM users or service accounts).

OPA is enabled through MinIO's Access Management Plugin feature.

## Get started

You will see something like this:

<img src="/img/tutorial/security/image01.png">

/// check | Authorize button!

You already have a shiny new "Authorize" button.

And your *path operation* has a little lock in the top-right corner that you can click.

///

Sie werden etwa Folgendes sehen:

<img src="/img/tutorial/security/image01.png">

/// check | Authorize-Button!

Sie haben bereits einen glänzenden, neuen „Authorize“-Button.

Und Ihre *Pfadoperation* hat in der oberen rechten Ecke ein kleines Schloss, auf das Sie klicken können.

///

  }

  /** See https://api.slack.com/docs/oauth. */
  public HttpUrl authorizeUrl(String scopes, HttpUrl redirectUrl, ByteString state, String team) {
    HttpUrl.Builder builder = baseUrl.newBuilder("/oauth/authorize")
        .addQueryParameter("client_id", clientId)
        .addQueryParameter("scope", scopes)
        .addQueryParameter("redirect_uri", redirectUrl.toString())
        .addQueryParameter("state", state.base64());

## List of metrics exposed by MinIO

- MinIO exports Prometheus compatible data by default as an authorized endpoint at `/minio/v2/metrics/cluster`. 
- MinIO exports Prometheus compatible data by default which is bucket centric as an authorized endpoint at `/minio/v2/metrics/bucket`.
- MinIO exports Prometheus compatible data by default which is node centric as an authorized endpoint at `/minio/v2/metrics/node`.

Open the interactive docs: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

### Authenticate { #authenticate }

Click the "Authorize" button.

Use the credentials:

User: `johndoe`

Password: `secret`

<img src="/img/tutorial/security/image04.png">

After authenticating in the system, you will see it like:

Verás algo así:

<img src="/img/tutorial/security/image01.png">

/// check | ¡Botón de autorización!

Ya tienes un nuevo y brillante botón de "Authorize".

Y tu *path operation* tiene un pequeño candado en la esquina superior derecha que puedes pulsar.

///

    /**
     * Default constructor.
     */
    public FessApiAdminAction() {
        super();
    }

    /**
     * Determines whether the current request is authorized to access admin API endpoints.
     * This method validates the access token and checks if the associated permissions
     * allow admin access according to the Fess configuration.
     *

		"s3:PutObject"
	  ],
	  "Effect": "Allow",
	  "Resource": ["arn:aws:s3:::mybucket/${aws:username}/*"]
	}
  ]
}
```

If the user is authenticating using an STS credential which was authorized from OpenID connect we allow all `jwt:*` variables specified in the JWT specification, custom `jwt:*` or extensions are not supported. List of policy variables for OpenID based STS.

- `jwt:sub`
- `jwt:iss`
- `jwt:aud`