Auto merge of #22597 - servo:tc-pr, r=jdm

Taskcluster: run tidy on PRs

Taskcluster: run tasks for PRs from everyone

These tasks should be untrusted, since they run before review. The `repo:github.com/servo/servo:pull-request` role determines what scopes (permissions) those tasks have.

https://tools.taskcluster.net/auth/roles/repo%3Agithub.com%2Fservo%2Fservo%3Apull-request

~For more paranoia, we could run these tasks on entirely separate worker types (machine pools). For now, maybe being careful to to give scopes for any kind of write access is hopefully enough.~

There seems to be no way to disable the "docker-in-docker" feature, which could allow tasks to escalate to root on the host worker. So this uses a separate `servo-docker-untrusted` worker type. To manage cost, these workers are configured with `minCapacity: 0` and to shut down after 2 minutes idle. (This is a trade-off with the latency of spinning up new AWS EC2 instances.)

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.taskcluster.yml

@@ -1,67 +1,100 @@
 version: 1
 policy:
   # https://docs.taskcluster.net/docs/reference/integrations/taskcluster-github/docs/taskcluster-yml-v1#pull-requests
-  pullRequests: collaborators
+  pullRequests: public
+
+  # NOTE: when updating this consider whether the daily hook needs similar changes:
+# https://tools.taskcluster.net/hooks/project-servo/daily
 tasks:
-  - $if: 'tasks_for == "github-push"'
+  $let:
-    then:
+    task_common:
-      $if: >-
+      provisionerId: aws-provisioner-v1
-        event.ref in ["refs/heads/auto", "refs/heads/try", "refs/heads/master"] ||
+      created: {$fromNow: ''}
-        event.ref[:15] == "refs/heads/try-"
+      deadline: {$fromNow: '1 day'}
+      extra:
+        treeherder:
+          machine: {platform: Linux}
+          labels: [x64]
+          symbol: Decision
+      payload:
+        maxRunTime: {$eval: '20 * 60'}
+        # https://github.com/servo/taskcluster-bootstrap-docker-images#decision-task
+        image: "servobrowser/taskcluster-bootstrap:decision-task@sha256:28045b7ec0485ef363f8cb14f194008b47e9ede99f2ea40a1e945e921fce976e"
+        features:
+          taskclusterProxy: true
+        env:
+          GIT_URL: ${event.repository.clone_url}
+          TASK_FOR: ${tasks_for}
+        command:
+          - /bin/bash
+          - '--login'
+          - '-e'
+          - '-c'
+          - >-
+            git init repo &&
+            cd repo &&
+            git fetch --depth 1 "$GIT_URL" "$GIT_REF" &&
+            git reset --hard "$GIT_SHA" &&
+            python3 etc/taskcluster/decision_task.py
+  in:
+    - $if: "tasks_for == 'github-push'"
       then:
+        $let:
+          branch:
+            $if: "event.ref[:11] == 'refs/heads/'"
+            then: "${event.ref[11:]}"
+        in:
+          $if: "branch in ['auto', 'try', 'master'] || branch[:4] == 'try-'"
+          then:
+            $mergeDeep:
+              - {$eval: "task_common"}
+              - metadata:
+                  name: "Servo: GitHub push decision task"
+                  description: ""
+                  owner: ${event.pusher.name}@users.noreply.github.com
+                  source: ${event.compare}
+                workerType: servo-docker-worker
+                scopes:
+                  - "assume:repo:github.com/servo/servo:branch:${branch}"
+                routes:
+                  $let:
+                    treeherder_repo:
+                      $if: "branch[:4] == 'try-'"
+                      then: "servo-${branch}"
+                      else: "servo-try"
+                  in:
+                    - "tc-treeherder.v2._/${treeherder_repo}.${event.after}"
+                    - "tc-treeherder-staging.v2._/${treeherder_repo}.${event.after}"
+                payload:
+                  env:
+                    GIT_REF: ${event.ref}
+                    GIT_SHA: ${event.after}
+                    TASK_OWNER: ${event.pusher.name}@users.noreply.github.com
+                    TASK_SOURCE: ${event.compare}
+    - $if: >-
+        tasks_for == 'github-pull-request' &&
+        event['action'] in ['opened', 'reopened', 'synchronize']
+      then:
+        $mergeDeep:
+          - {$eval: "task_common"}
+          - metadata:
+              name: "Servo: GitHub PR decision task"
+              description: ""
+              owner: ${event.sender.login}@users.noreply.github.com
+              source: ${event.pull_request.url}
+            workerType: servo-docker-untrusted
+            scopes:
+              - "assume:repo:github.com/servo/servo:pull-request"
+            routes:
+              - "tc-treeherder.v2._/servo-prs.${event.pull_request.head.sha}"
+              - "tc-treeherder-staging.v2._/servo-prs.${event.pull_request.head.sha}"
+            payload:
+              env:
+                # We use the merge commit made by GitHub, not the PR’s branch
+                GIT_REF: refs/pull/${event.pull_request.number}/merge
+                # `event.pull_request.merge_commit_sha` is tempting but not what we want:
+                # https://github.com/servo/servo/pull/22597#issuecomment-451518810
+                GIT_SHA: FETCH_HEAD
+                TASK_OWNER: ${event.sender.login}@users.noreply.github.com
+                TASK_SOURCE: ${event.pull_request.url}
 
-        # NOTE: when updating this consider whether the daily hook needs similar changes:
-        # https://tools.taskcluster.net/hooks/project-servo/daily
-
-        taskGroupId: {$eval: as_slugid("decision_task")}
-        taskId: {$eval: as_slugid("decision_task")}
-        provisionerId: aws-provisioner-v1
-        workerType: servo-docker-worker
-        created: {$fromNow: ''}
-        deadline: {$fromNow: '1 day'}
-        metadata:
-          name: "Servo: GitHub push decision task"
-          description: ""
-          owner: &task_owner ${event.pusher.name}@users.noreply.github.com
-          source: &task_source ${event.compare}
-        scopes:
-          - "assume:repo:github.com/servo/servo:branch:${event.ref[11:]}"
-        routes:
-          $let:
-            treeherder_repo:
-              $if: "event.ref[:15] != 'refs/heads/try-'"
-              then: "servo-${event.ref[11:]}"
-              else: "servo-try"
-          in:
-            - "tc-treeherder.v2._/${treeherder_repo}.${event.after}"
-            - "tc-treeherder-staging.v2._/${treeherder_repo}.${event.after}"
-        extra:
-          treeherder:
-            machine: {platform: Linux}
-            labels: [x64]
-            symbol: Decision
-
-        payload:
-          maxRunTime: {$eval: '20 * 60'}
-          # https://github.com/servo/taskcluster-bootstrap-docker-images#decision-task
-          image: "servobrowser/taskcluster-bootstrap:decision-task@sha256:28045b7ec0485ef363f8cb14f194008b47e9ede99f2ea40a1e945e921fce976e"
-          features:
-            taskclusterProxy: true
-          env:
-            GIT_URL: ${event.repository.clone_url}
-            GIT_REF: ${event.ref}
-            GIT_SHA: ${event.after}
-            TASK_FOR: ${tasks_for}
-            TASK_OWNER: *task_owner
-            TASK_SOURCE: *task_source
-          command:
-            - /bin/bash
-            - '--login'
-            - '-e'
-            - '-c'
-            - >-
-              git init repo &&
-              cd repo &&
-              git fetch --depth 1 "$GIT_URL" "$GIT_REF" &&
-              git reset --hard "$GIT_SHA" &&
-              python3 etc/taskcluster/decision_task.py

etc/taskcluster/decision_task.py

@@ -10,11 +10,11 @@ from decisionlib import CONFIG, SHARED
 
 
 def main(task_for):
-    assert CONFIG.git_ref.startswith("refs/heads/")
+    if CONFIG.git_ref.startswith("refs/heads/"):
-    branch = CONFIG.git_ref[len("refs/heads/"):]
+        branch = CONFIG.git_ref[len("refs/heads/"):]
-    CONFIG.treeherder_repository_name = "servo-" + (
+        CONFIG.treeherder_repository_name = "servo-" + (
-        branch if not branch.startswith("try-") else "try"
+            branch if not branch.startswith("try-") else "try"
-    )
+        )
 
     if task_for == "github-push":
         # FIXME https://github.com/servo/servo/issues/22325 implement these:
@@ -72,6 +72,17 @@ def main(task_for):
         for function in by_branch_name.get(branch, []):
             function()
 
+    elif task_for == "github-pull-request":
+        CONFIG.treeherder_repository_name = "servo-prs"
+        CONFIG.index_read_only = True
+
+        # We want the merge commit that GitHub creates for the PR.
+        # The event does contain a `pull_request.merge_commit_sha` key, but it is wrong:
+        # https://github.com/servo/servo/pull/22597#issuecomment-451518810
+        CONFIG.git_sha_is_current_head()
+
+        tidy_untrusted()
+
     # https://tools.taskcluster.net/hooks/project-servo/daily
     elif task_for == "daily":
         daily_tasks_setup()
@@ -120,6 +131,22 @@ windows_sparse_checkout = [
 ]
 
 
+def tidy_untrusted():
+    return (
+        decisionlib.DockerWorkerTask("Tidy")
+        .with_worker_type("servo-docker-untrusted")
+        .with_treeherder("Linux x64", "Tidy")
+        .with_max_run_time_minutes(60)
+        .with_dockerfile(dockerfile_path("build"))
+        .with_env(**build_env, **unix_build_env, **linux_build_env)
+        .with_repo()
+        .with_script("""
+            ./mach test-tidy --no-progress --all
+        """)
+        .create()
+    )
+
+
 def linux_tidy_unit_docs():
     return (
         linux_build_task("Tidy + dev build + unit tests + docs")
@@ -452,7 +479,7 @@ def daily_tasks_setup():
         "expires": SHARED.from_now_json(log_artifacts_expire_in),
     })
 
-    # Unlike when reacting to a GitHub event,
+    # Unlike when reacting to a GitHub push event,
     # the commit hash is not known until we clone the repository.
     CONFIG.git_sha_is_current_head()
 
@@ -511,7 +538,6 @@ def linux_build_task(name, *, build_env=build_env):
         .with_dockerfile(dockerfile_path("build"))
         .with_env(**build_env, **unix_build_env, **linux_build_env)
         .with_repo()
-        .with_index_and_artifacts_expire_in(build_artifacts_expire_in)
     )
 
 

etc/taskcluster/decisionlib.py

@@ -38,6 +38,7 @@ class Config:
     def __init__(self):
         self.task_name_template = "%s"
         self.index_prefix = "garbage.servo-decisionlib"
+        self.index_read_only = False
         self.scopes_for_all_subtasks = []
         self.routes_for_all_subtasks = []
         self.docker_image_buil_worker_type = None
@@ -265,7 +266,8 @@ class Task:
         except taskcluster.TaskclusterRestFailure as e:
             if e.status_code != 404:  # pragma: no cover
                 raise
-            self.routes.append("index.%s.%s" % (CONFIG.index_prefix, index_path))
+            if not CONFIG.index_read_only:
+                self.routes.append("index.%s.%s" % (CONFIG.index_prefix, index_path))
             task_id = self.create()
 
         SHARED.found_or_created_indexed_tasks[index_path] = task_id

etc/taskcluster/mock.py

@@ -62,4 +62,7 @@ decision_task.main("github-push")
 print("\n# Daily:")
 decision_task.main("daily")
 
+print("\n# PR:")
+decision_task.main("github-pull-request")
+
 print()

etc/taskcluster/simulate_github_events.py

@@ -0,0 +1,72 @@
+#!/bin/bash
+
+# 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 https://mozilla.org/MPL/2.0/.
+
+''''set -e
+cd "$(dirname $0)"
+exec ../../python/_virtualenv/bin/python "$(basename $0)"
+'''
+
+try:
+    import jsone
+except ImportError:
+    import sys
+    sys.exit("pip install git+https://github.com/taskcluster/json-e")
+
+import yaml
+import json
+
+template = yaml.load(open("../../.taskcluster.yml").read().decode("utf8"))
+repo = dict(
+    repository=dict(
+        clone_url="https://github.com/servo/servo.git",
+    ),
+)
+contexts = [
+    dict(
+        tasks_for="github-release",
+        event=repo,
+    ),
+    dict(
+        tasks_for="github-pull-request",
+        event=dict(
+            action="comment",
+            **repo
+        ),
+    ),
+    dict(
+        tasks_for="github-push",
+        event=dict(
+            ref="refs/heads/master",
+            compare="https://github.com/servo/servo/compare/1753cda...de09c8f",
+            after="de09c8fb6ef87dec5932d5fab4adcb421d291a54",
+            pusher=dict(
+                name="bors-servo",
+            ),
+            **repo
+        ),
+    ),
+    dict(
+        tasks_for="github-pull-request",
+        event=dict(
+            action="synchronize",
+            pull_request=dict(
+                number=22583,
+                url="https://github.com/servo/servo/pull/22583",
+                head=dict(
+                    sha="51a422c9ef47420eb69c802643b7686bdb498652",
+                ),
+                merge_commit_sha="876fcf7a5fe971a9ac0a4ce117906c552c08c095",
+            ),
+            sender=dict(
+                login="jdm",
+            ),
+            **repo
+        ),
+    ),
+]
+for context in contexts:
+    print(context["tasks_for"])
+    print(json.dumps(jsone.render(template, context), indent=2))