Improve configurability and OIDC support for the ARC Pulsar job runner

Rewrite the method `PulsarARCJobRunner.queue_job()` so that it:
- Obtains the ARC endpoint URL either from the user's preferences or the destination parameters.
- Requests an OIDC access token for the user running the job.
- Decides which OIDC provider to get the token from if multiple are available, based on the user's preferences and the destination parameters.

To let users configure their own settings, admins have to set the destination parameter "arc_user_preferences_key". Galaxy will then read the options "arc_url" and "arc_oidc_provider" under that key from the user extra preferences. Both are optional; if the user does not configure a value, the destination default will be used. If no destination default exists and the user account is associated with exactly one OIDC provider, then Galaxy will use that provider.

Author: kysrpex

lib/galaxy/jobs/runners/pulsar.py

@@ -40,6 +40,7 @@
 from sqlalchemy import select
 
 from galaxy import model
+from galaxy.authnz.util import provider_name_to_backend
 from galaxy.job_execution.compute_environment import (
     ComputeEnvironment,
     dataset_path_to_extra_path,
@@ -1090,19 +1091,64 @@ def get_client_from_state(self, job_state):
 
     def queue_job(self, job_wrapper):
         """
-        Inject user's own ARC endpoint and OIDC token (if defined) as destination parameters.
+        Queue a job to run it using the Pulsar ARC client.
+
+        ARC supports authentication via either x509 certificates or OIDC tokens. Since Galaxy only supports the latter
+        (through OIDC providers), the Pulsar ARC client implementation is designed to work with OIDC. Thus, to run jobs,
+        the Pulsar ARC client needs an ARC endpoint URL and an OIDC access token. Those are passed as destination
+        parameters.
+
+        OIDC tokens are, for obvious reasons, not meant to be part of the job configuration file nor of TPV
+        configuration files; they have to be obtained before the job is queued. For admins, it may also be interesting
+        to have a mechanism to inject an ARC endpoint URL from the user preferences, so that users can configure their
+        own ARC endpoint URLs.
+
+        Therefore, this method provides a framework to:
+        - Obtain an ARC endpoint URL from the user's preferences (if enabled).
+        - Obtain an OIDC access token for the user running the job.
+        - Decide which OIDC provider to obtain the token from if multiple are available.
+
+        To let users configure their own settings, admins have to set the destination parameter
+        "arc_user_preferences_key". Galaxy will then read the options "arc_url" and "arc_oidc_provider" under that key
+        from the user extra preferences. Both are optional; if the user does not configure any, the destination defaults
+        will be used. If no destination default exists and the user account is associated with exactly one OIDC
+        provider, then Galaxy will use that provider.
         """
-        destination_arc_url = job_wrapper.job_destination.params.get("arc_url")
-        destination_oidc_token = job_wrapper.job_destination.params.get("oidc_token")
-        user_arc_url = job_wrapper.get_job().user.extra_preferences.get("distributed_arc_compute|remote_arc_resources")
-        user_oidc_token = job_wrapper.get_job().user.extra_preferences.get("distributed_arc_compute|remote_arc_token")
+        job = job_wrapper.get_job()
+        user = job.user
 
-        job_wrapper.job_destination.params.update(
-            {
-                "arc_url": user_arc_url or destination_arc_url,
-                "oidc_token": user_oidc_token or destination_oidc_token,
-            }
+        extra_user_preferences_key = job_wrapper.job_destination.params.get("arc_user_preferences_key")
+        # for example, "distributed_compute_arc"
+
+        user_arc_url = (
+            user.extra_preferences.get(f"{extra_user_preferences_key}|arc_url") if extra_user_preferences_key else None
         )
+        user_arc_oidc_provider = (
+            user.extra_preferences.get(f"{extra_user_preferences_key}|arc_oidc_provider")
+            if extra_user_preferences_key
+            else None
+        )
+        destination_arc_url = job_wrapper.job_destination.params.get("arc_url")
+        destination_oidc_provider = job_wrapper.job_destination.params.get("arc_oidc_provider")
+        arc_url = user_arc_url or destination_arc_url
+        arc_oidc_provider = user_arc_oidc_provider or destination_oidc_provider
+        if arc_oidc_provider is None:
+            user_oidc_providers = [auth.provider for auth in user.custos_auth + user.social_auth]
+            if len(user_oidc_providers) > 1:
+                raise Exception(
+                    f"Multiple identity providers are linked to your user account '{user.username}', please select one "
+                    f"in your user preferences to launch ARC jobs."
+                )
+            elif len(user_oidc_providers) == 0:
+                raise Exception(
+                    f"No identity provider is linked to your user account '{user.username}', please log in using an "
+                    f"identity provider to launch ARC jobs."
+                )
+            arc_oidc_provider = user_oidc_providers[0]
+        arc_oidc_provider_backend = provider_name_to_backend(arc_oidc_provider)
+        arc_oidc_token = user.get_oidc_tokens(arc_oidc_provider_backend)["access"]
+
+        job_wrapper.job_destination.params.update({"arc_url": arc_url, "arc_oidc_token": arc_oidc_token})
 
         return super().queue_job(job_wrapper)