pr-agent/pr_agent/servers/github_app.py

import copy
import os
import asyncio.locks
import re
from typing import Any, Dict, List, Tuple

import uvicorn
from fastapi import APIRouter, FastAPI, HTTPException, Request, Response
from starlette.middleware import Middleware
from starlette_context import context
from starlette_context.middleware import RawContextMiddleware

from pr_agent.agent.pr_agent import PRAgent
from pr_agent.algo.utils import update_settings_from_args
from pr_agent.config_loader import get_settings, global_settings
from pr_agent.git_providers import get_git_provider
from pr_agent.git_providers.utils import apply_repo_settings
from pr_agent.git_providers.git_provider import IncrementalPR
from pr_agent.log import LoggingFormat, get_logger, setup_logger
from pr_agent.servers.utils import verify_signature, DefaultDictWithTimeout

setup_logger(fmt=LoggingFormat.JSON)

router = APIRouter()


@router.post("/api/v1/github_webhooks")
async def handle_github_webhooks(request: Request, response: Response):
    """
    Receives and processes incoming GitHub webhook requests.
    Verifies the request signature, parses the request body, and passes it to the handle_request function for further
    processing.
    """
    get_logger().debug("Received a GitHub webhook")

    body = await get_body(request)

    installation_id = body.get("installation", {}).get("id")
    context["installation_id"] = installation_id
    context["settings"] = copy.deepcopy(global_settings)

    response = await handle_request(body, event=request.headers.get("X-GitHub-Event", None))
    return response or {}


@router.post("/api/v1/marketplace_webhooks")
async def handle_marketplace_webhooks(request: Request, response: Response):
    body = await get_body(request)
    get_logger().info(f'Request body:\n{body}')


async def get_body(request):
    try:
        body = await request.json()
    except Exception as e:
        get_logger().error("Error parsing request body", e)
        raise HTTPException(status_code=400, detail="Error parsing request body") from e
    webhook_secret = getattr(get_settings().github, 'webhook_secret', None)
    if webhook_secret:
        body_bytes = await request.body()
        signature_header = request.headers.get('x-hub-signature-256', None)
        verify_signature(body_bytes, webhook_secret, signature_header)
    return body


_duplicate_push_triggers = DefaultDictWithTimeout(ttl=get_settings().github_app.push_trigger_pending_tasks_ttl)
_pending_task_duplicate_push_conditions = DefaultDictWithTimeout(asyncio.locks.Condition, ttl=get_settings().github_app.push_trigger_pending_tasks_ttl)

async def handle_comments_on_pr(body: Dict[str, Any],
                                event: str,
                                sender: str,
                                action: str,
                                log_context: Dict[str, Any],
                                agent: PRAgent):
    if "comment" not in body:
        return {}
    comment_body = body.get("comment", {}).get("body")
    if comment_body and isinstance(comment_body, str) and not comment_body.lstrip().startswith("/"):
        get_logger().info("Ignoring comment not starting with /")
        return {}
    disable_eyes = False
    if "issue" in body and "pull_request" in body["issue"] and "url" in body["issue"]["pull_request"]:
        api_url = body["issue"]["pull_request"]["url"]
    elif "comment" in body and "pull_request_url" in body["comment"]:
        api_url = body["comment"]["pull_request_url"]
        try:
            if ('/ask' in comment_body and
                    'subject_type' in body["comment"] and body["comment"]["subject_type"] == "line"):
                # comment on a code line in the "files changed" tab
                comment_body = handle_line_comments(body, comment_body)
                disable_eyes = True
        except Exception as e:
            get_logger().error(f"Failed to handle line comments: {e}")
    else:
        return {}
    log_context["api_url"] = api_url
    comment_id = body.get("comment", {}).get("id")
    provider = get_git_provider()(pr_url=api_url)
    with get_logger().contextualize(**log_context):
        get_logger().info(f"Processing comment on PR {api_url=}, comment_body={comment_body}")
        await agent.handle_request(api_url, comment_body,
                    notify=lambda: provider.add_eyes_reaction(comment_id, disable_eyes=disable_eyes))

async def handle_new_pr_opened(body: Dict[str, Any],
                               event: str,
                               sender: str,
                               action: str,
                               log_context: Dict[str, Any],
                               agent: PRAgent):
    title = body.get("pull_request", {}).get("title", "")

    # logic to ignore PRs with specific titles (e.g. "[Auto] ...")
    ignore_pr_title_re = get_settings().get("GITHUB_APP.IGNORE_PR_TITLE", [])
    if not isinstance(ignore_pr_title_re, list):
        ignore_pr_title_re = [ignore_pr_title_re]
    if ignore_pr_title_re and any(re.search(regex, title) for regex in ignore_pr_title_re):
        get_logger().info(f"Ignoring PR with title '{title}' due to github_app.ignore_pr_title setting")
        return {}

    pull_request, api_url = _check_pull_request_event(action, body, log_context)
    if not (pull_request and api_url):
        get_logger().info(f"Invalid PR event: {action=} {api_url=}")
        return {}
    if action in get_settings().github_app.handle_pr_actions:  # ['opened', 'reopened', 'ready_for_review', 'review_requested']
        await _perform_auto_commands_github("pr_commands", agent, body, api_url, log_context)

async def handle_push_trigger_for_new_commits(body: Dict[str, Any],
                        event: str,
                        sender: str,
                        action: str,
                        log_context: Dict[str, Any],
                        agent: PRAgent):
    pull_request, api_url = _check_pull_request_event(action, body, log_context)
    if not (pull_request and api_url):
        return {}

    apply_repo_settings(api_url) # we need to apply the repo settings to get the correct settings for the PR. This is quite expensive - a call to the git provider is made for each PR event.
    if not get_settings().github_app.handle_push_trigger:
        return {}

    # TODO: do we still want to get the list of commits to filter bot/merge commits?
    before_sha = body.get("before")
    after_sha = body.get("after")
    merge_commit_sha = pull_request.get("merge_commit_sha")
    if before_sha == after_sha:
        return {}
    if get_settings().github_app.push_trigger_ignore_merge_commits and after_sha == merge_commit_sha:
        return {}

    # Prevent triggering multiple times for subsequent push triggers when one is enough:
    # The first push will trigger the processing, and if there's a second push in the meanwhile it will wait.
    # Any more events will be discarded, because they will all trigger the exact same processing on the PR.
    # We let the second event wait instead of discarding it because while the first event was being processed,
    # more commits may have been pushed that led to the subsequent events,
    # so we keep just one waiting as a delegate to trigger the processing for the new commits when done waiting.
    current_active_tasks = _duplicate_push_triggers.setdefault(api_url, 0)
    max_active_tasks = 2 if get_settings().github_app.push_trigger_pending_tasks_backlog else 1
    if current_active_tasks < max_active_tasks:
        # first task can enter, and second tasks too if backlog is enabled
        get_logger().info(
            f"Continue processing push trigger for {api_url=} because there are {current_active_tasks} active tasks"
        )
        _duplicate_push_triggers[api_url] += 1
    else:
        get_logger().info(
            f"Skipping push trigger for {api_url=} because another event already triggered the same processing"
        )
        return {}
    async with _pending_task_duplicate_push_conditions[api_url]:
        if current_active_tasks == 1:
            # second task waits
            get_logger().info(
                f"Waiting to process push trigger for {api_url=} because the first task is still in progress"
            )
            await _pending_task_duplicate_push_conditions[api_url].wait()
            get_logger().info(f"Finished waiting to process push trigger for {api_url=} - continue with flow")

    try:
        if get_settings().github_app.push_trigger_wait_for_initial_review and not get_git_provider()(api_url,
                                                                                                     incremental=IncrementalPR(
                                                                                                             True)).previous_review:
            get_logger().info(f"Skipping incremental review because there was no initial review for {api_url=} yet")
            return {}
        get_logger().info(f"Performing incremental review for {api_url=} because of {event=} and {action=}")
        await _perform_auto_commands_github("push_commands", agent, body, api_url, log_context)

    finally:
        # release the waiting task block
        async with _pending_task_duplicate_push_conditions[api_url]:
            _pending_task_duplicate_push_conditions[api_url].notify(1)
            _duplicate_push_triggers[api_url] -= 1


async def handle_request(body: Dict[str, Any], event: str):
    """
    Handle incoming GitHub webhook requests.

    Args:
        body: The request body.
        event: The GitHub event type (e.g. "pull_request", "issue_comment", etc.).
    """
    action = body.get("action") # "created", "opened", "reopened", "ready_for_review", "review_requested", "synchronize"
    if not action:
        return {}
    agent = PRAgent()
    sender = body.get("sender", {}).get("login")
    log_context = {"action": action, "event": event, "sender": sender, "server_type": "github_app"}

    # handle comments on PRs
    if action == 'created':
        get_logger().debug(f'Request body', body=body)
        await handle_comments_on_pr(body, event, sender, action, log_context, agent)
    # handle new PRs
    elif event == 'pull_request' and action != 'synchronize':
        get_logger().debug(f'Request body', body=body)
        await handle_new_pr_opened(body, event, sender, action, log_context, agent)
    # handle pull_request event with synchronize action - "push trigger" for new commits
    elif event == 'pull_request' and action == 'synchronize':
        get_logger().debug(f'Request body', body=body)
        await handle_push_trigger_for_new_commits(body, event, sender, action, log_context, agent)
    else:
        get_logger().info(f"event {event=} action {action=} does not require any handling")
        return {}


def handle_line_comments(body: Dict, comment_body: [str, Any]) -> str:
    if not comment_body:
        return ""
    start_line = body["comment"]["start_line"]
    end_line = body["comment"]["line"]
    start_line = end_line if not start_line else start_line
    question = comment_body.replace('/ask', '').strip()
    diff_hunk = body["comment"]["diff_hunk"]
    get_settings().set("ask_diff_hunk", diff_hunk)
    path = body["comment"]["path"]
    side = body["comment"]["side"]
    comment_id = body["comment"]["id"]
    if '/ask' in comment_body:
        comment_body = f"/ask_line --line_start={start_line} --line_end={end_line} --side={side} --file_name={path} --comment_id={comment_id} {question}"
    return comment_body


def _check_pull_request_event(action: str, body: dict, log_context: dict) -> Tuple[Dict[str, Any], str]:
    invalid_result = {}, ""
    pull_request = body.get("pull_request")
    if not pull_request:
        return invalid_result
    api_url = pull_request.get("url")
    if not api_url:
        return invalid_result
    log_context["api_url"] = api_url
    if pull_request.get("draft", True) or pull_request.get("state") != "open":
        return invalid_result
    if action in ("review_requested", "synchronize") and pull_request.get("created_at") == pull_request.get("updated_at"):
        # avoid double reviews when opening a PR for the first time
        return invalid_result
    return pull_request, api_url


async def _perform_auto_commands_github(commands_conf: str, agent: PRAgent, body: dict, api_url: str, log_context: dict):
    apply_repo_settings(api_url)
    commands = get_settings().get(f"github_app.{commands_conf}")
    if not commands:
        with get_logger().contextualize(**log_context):
            get_logger().info(f"New PR, but no auto commands configured")
        return
    for command in commands:
        split_command = command.split(" ")
        command = split_command[0]
        args = split_command[1:]
        other_args = update_settings_from_args(args)
        new_command = ' '.join([command] + other_args)
        with get_logger().contextualize(**log_context):
            get_logger().info(f"New PR opened. Performing auto command '{new_command}', for {api_url=}")
            await agent.handle_request(api_url, new_command)


@router.get("/")
async def root():
    return {"status": "ok"}


if get_settings().github_app.override_deployment_type:
    # Override the deployment type to app
    get_settings().set("GITHUB.DEPLOYMENT_TYPE", "app")
get_settings().set("CONFIG.PUBLISH_OUTPUT_PROGRESS", False)
middleware = [Middleware(RawContextMiddleware)]
app = FastAPI(middleware=middleware)
app.include_router(router)


def start():
    uvicorn.run(app, host="0.0.0.0", port=int(os.environ.get("PORT", "3000")))

if __name__ == '__main__':
    start()