Creating Clients

The process for getting user credentials is designed for other frontend applications that can use OIDC flow. That does not work for command-line tools.

Tools provides an alternative flow to support non-OIDC applications. The process involves a browser and a redirect flow that finishes at a URL pointing to a local server, containing Taskcluster credentials. For command-line tools, this is a small webserver running within the tool itself. The tool itself requests that the user either create a new client or reset the accessToken for an existing client.

The tool should open a new browser window with a URL with prefix and the following URL-encoded query parameters:

  • name -- name suffix for the client
  • description -- description of the client
  • scope (can be repeated) -- scopes the new client will need
  • expires -- time until the new client expires
  • callback_url -- URL to which the resulting credentials will be sent

The name should be the same from one invocation to the next by the same tool, allowing the user to re-use an existing client of the same name. The clientId will be created by appending the name to a prefix where the user has permission to create clients. The description will become the description of the newly-created user.

The scope parameter can be specified multiple times, and allows the creation of a client with only the required scopes -- a good security practice. The resulting client's scopes are the intersection of the user's scopes and the scope parameters. For example, a tool for administering the hooks service might request ?scope=hooks:*&scope=assume:hook-id:*.

The expires parameter specifies a lifetime for the resulting clientId, in a format defined by taskcluster-client's fromNow. For example, ?expires=3h would result in credentials expiring in 3 hours.

Finally, callback_url is the URL to which the user's browser should be redirected with the resulting client. It is called with the URL-encoded query parameters clientId and accessToken. When this URL is accessed, the command-line tool should respond with some simple HTML for the browser to display, then extract the credentials from the URL and use them as desired.