GH-33977: [Dev] PR Workflow automation bot

.github/workflows/pr_bot.yml

@@ -0,0 +1,97 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+name: "Workflow label bot"
+on:
+  pull_request_target:
+    types:
+      - opened
+      - converted_to_draft
+      - ready_for_review
+      - synchronize
+  workflow_run:
+    workflows: ["Label when reviewed"]
+    types: ['completed']
+
+permissions:
+  contents: read
+  pull-requests: write
+  issues: write
+
+jobs:
+  pr-workflow-bot-job:
+    name: "PR Workflow bot"
+    runs-on: ubuntu-latest
+    steps:
+      - name: 'Download PR review payload'
+        id: 'download'
+        if: github.event_name == 'workflow_run'
+        uses: actions/github-script@v6
+        with:
+          script: |
+            const run_id = "${{ github.event.workflow_run.id }}";
+            let artifacts = await github.rest.actions.listWorkflowRunArtifacts({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              run_id: run_id,
+            });
+            let pr_review_artifact = artifacts.data.artifacts.filter((artifact) => {
+              return artifact.name == "pr_review_payload"
+            })[0];
+            let pr_review_download = await github.rest.actions.downloadArtifact({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              artifact_id: pr_review_artifact.id,
+              archive_format: 'zip',
+            });
+            var fs = require('fs');
+            fs.writeFileSync('${{github.workspace}}/pr_review.zip', Buffer.from(pr_review_download.data));
+      - name: Extract artifact
+        id: extract
+        if: github.event_name == 'workflow_run'
+        run: |
+          unzip pr_review.zip
+          echo "pr_review_path=$(pwd)/event.json" >> $GITHUB_OUTPUT
+      - name: Checkout Arrow
+        uses: actions/checkout@v3
+        with:
+          path: arrow
+          repository: apache/arrow
+          ref: main
+          persist-credentials: false
+          # fetch the tags for version number generation
+          fetch-depth: 0
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.8
+      - name: Install Archery and Crossbow dependencies
+        run: pip install -e arrow/dev/archery[bot]
+      - name: Handle PR workflow event
+        env:
+          ARROW_GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          if [ "${GITHUB_EVENT_NAME}" = "workflow_run" ]; then
+            # workflow_run is executed on PR review. Update to original event.
+            archery trigger-bot \
+              --event-name "pull_request_review" \
+              --event-payload "${{ steps.extract.outputs.pr_review_path }}"
+          else
+            archery trigger-bot \
+              --event-name "${{ github.event_name }}" \
+              --event-payload "${{ github.event_path }}"
+          fi

.github/workflows/pr_review_trigger.yml

@@ -0,0 +1,32 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+name: "Label when reviewed"
+on: pull_request_review
+
+jobs:
+  # due to GitHub Actions permissions we can't change labels on the pull_request_review
+  # workflow. We trigger a new workflow run which will have permissions to add labels.
+  label-when-reviewed:
+    name: "Label PRs when reviewed"
+    runs-on: ubuntu-latest
+    steps:
+      - name: "Upload PR review Payload"
+        uses: actions/upload-artifact@v3
+        with:
+          path: "${{ github.event_path }}"
+          name: "pr_review_payload"

dev/archery/archery/bot.py

@@ -15,10 +15,11 @@
 # specific language governing permissions and limitations
 # under the License.
 
+import enum
 import os
 import shlex
 from pathlib import Path
-from functools import partial
+from functools import lru_cache, partial
 import tempfile
 
 import click
@@ -29,6 +30,10 @@
 from .crossbow import Repo, Queue, Config, Target, Job, CommentReport
 
 
+def cached_property(fn):
+    return property(lru_cache(maxsize=1)(fn))
+
+
 class EventError(Exception):
     pass
 
@@ -82,6 +87,122 @@ def parse_args(self, ctx, args):
 group = partial(click.group, cls=Group)
 
 
+LABEL_PREFIX = "awaiting"
+
+
+@enum.unique
+class PullRequestState(enum.Enum):
+    """State of a pull request."""
+
+    review = f"{LABEL_PREFIX} review"
+    committer_review = f"{LABEL_PREFIX} committer review"
+    changes = f"{LABEL_PREFIX} changes"
+    change_review = f"{LABEL_PREFIX} change review"
+    merge = f"{LABEL_PREFIX} merge"
+
+
+COMMITTER_ROLES = {'OWNER', 'MEMBER'}
+
+
+class PullRequestWorkflowBot:
+
+    def __init__(self, event_name, event_payload, token=None):
+        self.github = github.Github(token)
+        self.event_name = event_name
+        self.event_payload = event_payload
+
+    @cached_property
+    def pull(self):
+        """
+        Returns a github.PullRequest object associated with the event.
+        """
+        return self.repo.get_pull(self.event_payload['pull_request']['number'])
+
+    @cached_property
+    def repo(self):
+        return self.github.get_repo(self.event_payload['repository']['id'], lazy=True)
+
+    def handle(self):
+        current_state = None
+        try:
+            current_state = self.get_current_state()
+        except EventError:
+            # In case of error (more than one state) we clear state labels
+            # only possible if a label has been manually added.
+            self.clear_current_state()
+        next_state = self.compute_next_state(current_state)
+        if not current_state or current_state != next_state:
+            if current_state:
+                self.clear_current_state()
+            self.set_state(next_state)
+
+    def get_current_state(self):
+        """
+        Returns a PullRequestState with the current PR state label
+        based on label starting with LABEL_PREFIX.
+        If more than one label is found raises EventError.
+        If no label is found returns None.
+        """
+        states = [label.name for label in self.pull.get_labels()
+                  if label.name.startswith(LABEL_PREFIX)]
+        if len(states) > 1:
+            raise EventError(f"PR cannot be on more than one states - {states}")
+        elif states:
+            return PullRequestState(states[0])
+
+    def clear_current_state(self):
+        """
+        Removes all existing labels starting with LABEL_PREFIX
+        """
+        for label in self.pull.get_labels():
+            if label.name.startswith(LABEL_PREFIX):
+                self.pull.remove_from_labels(label)
+
+    def compute_next_state(self, current_state):
+        """
+        Returns the expected next state based on the event and
+        the current state.
+        """
+        if (self.event_name == "pull_request_target" and
+                self.event_payload['action'] == 'opened'):
+            if (self.event_payload['pull_request']['author_association'] in
+                    COMMITTER_ROLES):
+                return PullRequestState.committer_review
+            else:
+                return PullRequestState.review
+        elif (self.event_name == "pull_request_review" and
+                self.event_payload["action"] == "submitted"):
+            review_state = self.event_payload["review"]["state"].lower()
+            is_committer_review = (self.event_payload['review']['author_association']
+                                   in COMMITTER_ROLES)
+            if not is_committer_review:
+                # Non-committer reviews cannot change state once committer has already
+                # reviewed, requested changes or approved
+                if current_state in (
+                        PullRequestState.change_review,
+                        PullRequestState.changes,
+                        PullRequestState.merge):
+                    return current_state
+                else:
+                    return PullRequestState.committer_review
+            if review_state == 'approved':
+                return PullRequestState.merge
+            else:
+                return PullRequestState.changes
+        elif (self.event_name == "pull_request_target" and
+              self.event_payload['action'] == 'synchronize' and
+              current_state == PullRequestState.changes):
+            return PullRequestState.change_review
+        # Default already opened PRs to Review state.
+        if current_state is None:
+            current_state = PullRequestState.review
+        return current_state
+
+    def set_state(self, state):
+        """Sets the State label to the PR."""
+        self.pull.add_to_labels(state.value)
+
+
 class CommentBot:
 
     def __init__(self, name, handler, token=None):

dev/archery/archery/cli.py

@@ -781,12 +781,15 @@ def integration(with_all=False, random_seed=12345, **args):
 @click.option('--arrow-token', envvar='ARROW_GITHUB_TOKEN',
               help='OAuth token for responding comment in the arrow repo')
 def trigger_bot(event_name, event_payload, arrow_token):
-    from .bot import CommentBot, actions
+    from .bot import CommentBot, PullRequestWorkflowBot, actions
 
     event_payload = json.loads(event_payload.read())
-
-    bot = CommentBot(name='github-actions', handler=actions, token=arrow_token)
-    bot.handle(event_name, event_payload)
+    if 'comment' in event_name:
+        bot = CommentBot(name='github-actions', handler=actions, token=arrow_token)
+        bot.handle(event_name, event_payload)
+    else:
+        bot = PullRequestWorkflowBot(event_name, event_payload, token=arrow_token)
+        bot.handle()
 
 
 @archery.group("linking")