[CI] Validate scraped push commits via GitHub API (llvm#514)

As GitHubArchive BigQuery is known to be lossy, it is likely that we
currently overestimate the number of commits made to llvm/llvm-project
without an associated pull request.

To remedy this, we can make calls to the [GitHub Event
API](https://docs.github.com/en/rest/activity/events). While we want to
avoid using the API to get information regarding every single commit
made to LLVM, we can narrow our calls down to only commits that don't
have any pull request data available via BigQuery. From those calls, we
can determine if a "push" commit actually does have a pull request and,
if it does, whether or not it has been approved.

Author: jriv01

llvm-ops-metrics/ops-container/process_llvm_commits.py

@@ -9,8 +9,13 @@
 GRAFANA_URL = (
     "https://influx-prod-13-prod-us-east-0.grafana.net/api/v1/push/influx/write"
 )
+GITHUB_GRAPHQL_API_URL = "https://api.github.com/graphql"
 REPOSITORY_URL = "https://github.com/llvm/llvm-project.git"
 
+# How many commits to query the GitHub GraphQL API for at a time.
+# Querying too many commits at once often leads to the call failing.
+GITHUB_API_BATCH_SIZE = 75
+
 # Number of days to look back for new commits
 # We allow some buffer time between when a commit is made and when it is queried
 # for reviews. This is allow time for any events to propogate in the GitHub
@@ -44,6 +49,23 @@
   AND JSON_VALUE(pr_event.payload, '$.pull_request.merge_commit_sha') IS NOT NULL
 """
 
+# Template GraphQL subquery to check if a commit has an associated pull request
+# and whether that pull request has been reviewed and approved.
+COMMIT_GRAPHQL_SUBQUERY_TEMPLATE = """
+commit_{commit_sha}:
+  object(oid:"{commit_sha}") {{
+    ... on Commit {{
+      associatedPullRequests(first: 1) {{
+        totalCount
+        pullRequest: nodes {{
+          number
+          reviewDecision
+        }}
+      }}
+    }}
+  }}
+"""
+
 
 @dataclasses.dataclass
 class LLVMCommitInfo:
@@ -153,6 +175,85 @@ def query_for_reviews(
   return list(new_commits.values())
 
 
+def validate_push_commits(
+    new_commits: list[LLVMCommitInfo], github_token: str
+) -> None:
+  """Validate that push commits don't have a pull request.
+
+  To address lossiness of data from GitHub Archive BigQuery, we check each
+  commit to see if it actually has an associated pull request.
+
+  Args:
+    new_commits: List of commits to validate.
+    github_token: The access token to use with the GitHub GraphQL API.
+  """
+
+  # Get all push commits from new commits and form their subqueries
+  commit_subqueries = []
+  potential_push_commits = {}
+  for commit in new_commits:
+    if commit.has_pull_request:
+      continue
+    potential_push_commits[commit.commit_sha] = commit
+    commit_subqueries.append(
+        COMMIT_GRAPHQL_SUBQUERY_TEMPLATE.format(commit_sha=commit.commit_sha)
+    )
+  logging.info("Found %d potential push commits", len(potential_push_commits))
+
+  # Query GitHub GraphQL API for pull requests associated with push commits
+  # We query in batches as large queries often fail
+  api_commit_data = {}
+  query_template = """
+    query {
+      repository(owner:"llvm", name:"llvm-project"){
+          %s
+      }
+    }
+  """
+  num_batches = len(commit_subqueries) // GITHUB_API_BATCH_SIZE + 1
+  logging.info("Querying GitHub GraphQL API in %d batches", num_batches)
+  for i in range(num_batches):
+    subquery_batch = commit_subqueries[
+        i * GITHUB_API_BATCH_SIZE : (i + 1) * GITHUB_API_BATCH_SIZE
+    ]
+    query = query_template % "".join(subquery_batch)
+
+    logging.info(
+        "Querying batch %d of %d (%d commits)",
+        i + 1,
+        num_batches,
+        len(subquery_batch),
+    )
+    response = requests.post(
+        url=GITHUB_GRAPHQL_API_URL,
+        headers={
+            "Authorization": f"bearer {github_token}",
+        },
+        json={"query": query},
+    )
+    if response.status_code < 200 or response.status_code >= 300:
+      logging.error("Failed to query GitHub GraphQL API: %s", response.text)
+    api_commit_data.update(response.json()["data"]["repository"])
+
+  amend_count = 0
+  for commit_sha, data in api_commit_data.items():
+    # Verify that push commit has no pull requests
+    commit_sha = commit_sha.removeprefix("commit_")
+    if data["associatedPullRequests"]["totalCount"] == 0:
+      continue
+
+    # Amend fields with new data from API
+    pull_request = data["associatedPullRequests"]["pullRequest"][0]
+    commit_info = potential_push_commits[commit_sha]
+    commit_info.has_pull_request = True
+    commit_info.pr_number = pull_request["number"]
+    commit_info.is_reviewed = pull_request["reviewDecision"] is not None
+    commit_info.is_approved = pull_request["reviewDecision"] == "APPROVED"
+    amend_count += 1
+
+  logging.info("Amended %d commits", amend_count)
+
+
 def upload_daily_metrics(
     grafana_api_key: str,
     grafana_metrics_userid: str,
@@ -164,9 +265,6 @@ def upload_daily_metrics(
     grafana_api_key: The key to make API requests with.
     grafana_metrics_userid: The user to make API requests with.
     new_commits: List of commits to process & upload to Grafana.
-
-  Returns:
-    None
   """
   # Count each type of commit made
   approval_count = 0
@@ -200,6 +298,7 @@ def upload_daily_metrics(
 
 
 def main() -> None:
+  github_token = os.environ["GITHUB_TOKEN"]
   grafana_api_key = os.environ["GRAFANA_API_KEY"]
   grafana_metrics_userid = os.environ["GRAFANA_METRICS_USERID"]
 
@@ -219,6 +318,9 @@ def main() -> None:
   logging.info("Querying for reviews of new commits.")
   new_commit_info = query_for_reviews(new_commits, date_to_scrape)
 
+  logging.info("Validating push commits.")
+  validate_push_commits(new_commit_info, github_token)
+
   logging.info("Uploading metrics to Grafana.")
   upload_daily_metrics(grafana_api_key, grafana_metrics_userid, new_commit_info)