Setup a PR review bot

.github/workflows/pr_review_bot.yaml

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+name: Bot Review
+
+on:
+  pull_request:
+    types:
+      - opened
+      - edited
+jobs:
+  bot_review:
+    runs-on: ubuntu-latest
+
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+
+      - name: Set Up Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+
+      - name: Install Dependencies
+        run: pip install PyGithub requests
+
+      - name: Run Bot Review
+        run: python scripts/review_bot.py "${{ github.event_path }}"
+
+

scripts/review_bot.py

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+
+import sys
+import json
+import re
+import os
+import requests
+from github import Github
+
+BOT_REVIEW_LABEL = "bot-review"
+GRAPHQL_ENDPOINT = "https://api.github.com/graphql"
+
+# Read the pr event file, which is passed in as first arg
+def read_pr_event():
+    with open(sys.argv[1], 'r') as file:
+        event_payload = json.load(file)
+    return event_payload
+
+# Read template file
+def read_template_file():
+    template_file_path = ".github/pull_request_template.md"
+    with open(template_file_path, 'r') as template_file:
+        combined_templates = template_file.read()
+    return combined_templates
+
+# Separate out each template
+template_separator = re.compile(r"<!--- \*{5} Template: (.*?) \*{5}\n\n(.*?)\n\n-->", re.DOTALL)
+def separate_templates(combined_templates):
+    matches = template_separator.findall(combined_templates)
+    for (name,content) in matches:
+        yield name,content
+
+# Find fields in a template or pull request. They look like **field name**
+field_finder = re.compile(r"\*{2}(.+?)\*{2}")
+def find_field_set(content):
+    return set(field_finder.findall(content))
+
+# use GraphQL to get pull request id
+def get_pull_request_graphql_id(accessToken,name,number):
+    headers = {"Authorization": f"Bearer {accessToken}"}
+    owner,name = name.split('/')
+    query = f"""query {{
+      repository(owner:"{owner}", name:"{name}"){{
+        pullRequest(number: {number}) {{
+            id
+        }}
+      }}
+    }}"""
+    r = requests.post(GRAPHQL_ENDPOINT, json={"query": query}, headers=headers)
+    return r.json()["data"]["repository"]["pullRequest"]["id"]
+
+# use GraphQL to set pull request as draft
+def set_pr_draft(accessToken,id):
+    headers = {"Authorization": f"Bearer {accessToken}"}
+    query = f"""mutation {{
+        convertPullRequestToDraft(input:{{pullRequestId:"{id}"}}){{
+            pullRequest {{
+                id
+            }}
+        }}
+    }}"""
+    requests.post(GRAPHQL_ENDPOINT, json={"query": query}, headers=headers)
+
+# use GraphQL to set pull request as ready
+def set_pr_ready(accessToken,id):
+    headers = {"Authorization": f"Bearer {accessToken}"}
+    query = f"""mutation {{
+        markPullRequestReadyForReview(input:{{pullRequestId:"{id}"}}){{
+            pullRequest {{
+                id
+            }}
+        }}
+    }}"""
+    requests.post(GRAPHQL_ENDPOINT, json={"query": query}, headers=headers)
+
+if __name__ == "__main__":
+    accessToken = os.environ['GITHUB_TOKEN']
+    g = Github(accessToken)
+
+    pr_event = read_pr_event()
+    repo_name = pr_event['repository']['full_name']
+    pr_number = pr_event['pull_request']['number']
+    pr_id = get_pull_request_graphql_id(accessToken,repo_name,pr_number)
+    pr_body = pr_event["pull_request"]["body"]
+    pr = g.get_repo(repo_name).get_pull(pr_number)
+    pr.add_to_labels(BOT_REVIEW_LABEL)
+    set_pr_draft(accessToken,pr_id)
+
+    fields_in_pr_body = find_field_set(pr_body)
+    combined_templates = read_template_file()
+    templates = separate_templates(combined_templates)
+
+    # Calculate which templates match
+    possible_template_matches = []
+    for template_name,template_content in templates:
+        required_fields = find_field_set(template_content)
+        if fields_in_pr_body.issuperset(required_fields):
+            possible_template_matches.append(template_name)
+
+    # Return results
+    if len(possible_template_matches) > 0:
+        print("PR matches template(s): ",", ".join(possible_template_matches))
+        pr.remove_from_labels(BOT_REVIEW_LABEL)
+        set_pr_ready(accessToken,pr_id)
+        sys.exit(0) # Pass
+    else:
+        print("PR does not match any known templates")
+        sys.exit(1) # Fail
+