Service-to-Service Authentication

Service to Service (S2S) authentication provides an easy-to-use interface for applications to retrieve a JSON web token (JWT). By using this token, applications can access data from other resources.

In order to integrate service-to-service authentication into your application follow the instructions below.

Important

Service-to-Service authentication is not available for apps which are installed from "unkown sources". Only apps which have been validated & digitally signed by Bosch Rexroth AG are permitted to use the interface.

Add Content Plug to snapcraft.yaml

To be able to retrieve a token, the app has to provide two content slots. The definition for those slots must be added to the snapcraft.yaml:

slots:
  secure-assets:
    interface: content
    content: secure-assets
    target: $SNAP/secure-assets/${SNAPCRAFT_PROJECT_NAME}
  service-token:
    interface: content
    content: service-token
    source:
      write:
        - $SNAP_DATA/service-token/${SNAPCRAFT_PROJECT_NAME}

Important

The target of the secure-assets slot must point to a location in the read-only area of the application ($SNAP, see example above). The app validation will fail if this rule is violated.

Define & Provide Permissions (secure-assets)

The application must provide a file named ${SNAP_NAME}.scopes.json located in $SNAP/secure-assets/${SNAPCRAFT_PROJECT_NAME} which defines the permissions that are requested by the application. One example would be:

{
  "id": "myapp",
  "required-permissions": ["logbook.diag.r", "rexroth-deviceadmin.web.licensemanager.r"]
}

In this example, your app would request a token which provides access to the logbook (read-only) and the License Manager backend (read-only).

Important

The parameter id must match the id that is defined in the Package Manifest (refer to Package Manifest documentation for details)

Retrieve and Use Authentication Token (service-token)

During runtime, the token will be provided to the application as a file named <id>.token (in the example shown above, this would be myapp.token) in the service-token folder ($SNAP_DATA/service-token/${SNAPCRAFT_PROJECT_NAME}).

Important

The content of the token file might not be up-to-date when the application is ready, especially after a (re-)start of the system. Using an outdated token will lead to an authentication failure. Therefore, the application must implement a logic which - if the authentication request has failed - parses the token file again and tries to re-authenticate. This must be repeated until the authentication succeeds.