ci: index docker-images by pull request number

taskcluster/kinds/docker-image/kind.yml

@@ -10,6 +10,7 @@ loader: taskgraph.loader.transform:loader
 transforms:
     - taskgraph.transforms.docker_image:transforms
     - taskgraph.transforms.cached_tasks:transforms
+    - self_taskgraph.transforms.add_pr_route
     - taskgraph.transforms.task:transforms
 
 # make a task for each docker-image we might want.  For the moment, since we

taskcluster/self_taskgraph/custom_parameters.py

@@ -2,7 +2,30 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import os
+
+from voluptuous import All, Any, Range, Required
+
+from taskgraph.parameters import extend_parameters_schema
+
+
+def get_defaults(repo_root):
+    return {
+        "pull_request_number": None,
+    }
+
+
+extend_parameters_schema(
+    {
+        Required("pull_request_number"): Any(All(int, Range(min=1)), None),
+    },
+    defaults_fn=get_defaults,
+)
+
 
 def decision_parameters(graph_config, parameters):
     if parameters["tasks_for"] == "github-release":
         parameters["target_tasks_method"] = "release"
+
+    pr_number = os.environ.get("TASKGRAPH_PULL_REQUEST_NUMBER", None)
+    parameters["pull_request_number"] = None if pr_number is None else int(pr_number)

taskcluster/self_taskgraph/transforms/add_pr_route.py

@@ -0,0 +1,31 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from taskgraph.transforms.base import TransformSequence
+
+transforms = TransformSequence()
+
+
+@transforms.add
+def add_pr_route(config, tasks):
+    """Adds pull request index routes when applicable."""
+    if not (pr_number := config.params.get("pull_request_number")):
+        yield from tasks
+        return
+
+    PR_ROUTE = (
+        "index.{trust-domain}.v2.{project}-pr.{pr-number}.latest.{kind}.{task-name}"
+    )
+    subs = {
+        "trust-domain": config.graph_config["trust-domain"],
+        "project": config.params["project"],
+        "pr-number": pr_number,
+        "kind": config.kind,
+    }
+
+    for task in tasks:
+        subs["task-name"] = task.get("name") or task["label"][len(config.kind) + 1 :]
+        routes = task.setdefault("routes", [])
+        routes.append(PR_ROUTE.format(**subs))
+        yield task

taskcluster/test/params/main-repo-pull-request-untrusted.yml

@@ -17,6 +17,7 @@ moz_build_date: '20220421203159'
 optimize_target_tasks: true
 owner: [email protected]
 project: taskgraph
+pull_request_number: 123
 pushdate: 0
 pushlog_id: '0'
 repository_type: git

taskcluster/test/params/main-repo-pull-request.yml

@@ -17,6 +17,7 @@ moz_build_date: '20220421203159'
 optimize_target_tasks: true
 owner: [email protected]
 project: taskgraph
+pull_request_number: 123
 pushdate: 0
 pushlog_id: '0'
 repository_type: git