aurweb/aurweb/asgi.py
Leonidas Spyropoulos 9c0f8f053e
chore: rename logging.py and redis.py to avoid circular imports
Signed-off-by: Leonidas Spyropoulos <artafinde@archlinux.org>
2022-10-22 18:51:38 +01:00

322 lines
11 KiB
Python

import hashlib
import http
import io
import os
import re
import sys
import traceback
import typing
from urllib.parse import quote_plus
import requests
from fastapi import FastAPI, HTTPException, Request, Response
from fastapi.responses import RedirectResponse
from fastapi.staticfiles import StaticFiles
from jinja2 import TemplateNotFound
from prometheus_client import multiprocess
from sqlalchemy import and_, or_
from starlette.exceptions import HTTPException as StarletteHTTPException
from starlette.middleware.authentication import AuthenticationMiddleware
from starlette.middleware.sessions import SessionMiddleware
import aurweb.captcha # noqa: F401
import aurweb.config
import aurweb.filters # noqa: F401
import aurweb.pkgbase.util as pkgbaseutil
from aurweb import aur_logging, prometheus, util
from aurweb.aur_redis import redis_connection
from aurweb.auth import BasicAuthBackend
from aurweb.db import get_engine, query
from aurweb.models import AcceptedTerm, Term
from aurweb.packages.util import get_pkg_or_base
from aurweb.prometheus import instrumentator
from aurweb.routers import APP_ROUTES
from aurweb.templates import make_context, render_template
logger = aur_logging.get_logger(__name__)
# Setup the FastAPI app.
app = FastAPI()
# Instrument routes with the prometheus-fastapi-instrumentator
# library with custom collectors and expose /metrics.
instrumentator().add(prometheus.http_api_requests_total())
instrumentator().add(prometheus.http_requests_total())
instrumentator().instrument(app)
@app.on_event("startup")
async def app_startup():
# https://stackoverflow.com/questions/67054759/about-the-maximum-recursion-error-in-fastapi
# Test failures have been observed by internal starlette code when
# using starlette.testclient.TestClient. Looking around in regards
# to the recursion error has really not recommended a course of action
# other than increasing the recursion limit. For now, that is how
# we handle the issue: an optional TEST_RECURSION_LIMIT env var
# provided by the user. Docker uses .env's TEST_RECURSION_LIMIT
# when running test suites.
# TODO: Find a proper fix to this issue.
recursion_limit = int(
os.environ.get("TEST_RECURSION_LIMIT", sys.getrecursionlimit() + 1000)
)
sys.setrecursionlimit(recursion_limit)
backend = aurweb.config.get("database", "backend")
if backend not in aurweb.db.DRIVERS:
raise ValueError(
f"The configured database backend ({backend}) is unsupported. "
f"Supported backends: {str(aurweb.db.DRIVERS.keys())}"
)
session_secret = aurweb.config.get("fastapi", "session_secret")
if not session_secret:
raise Exception("[fastapi] session_secret must not be empty")
if not os.environ.get("PROMETHEUS_MULTIPROC_DIR", None):
logger.warning(
"$PROMETHEUS_MULTIPROC_DIR is not set, the /metrics "
"endpoint is disabled."
)
app.mount("/static/css", StaticFiles(directory="web/html/css"), name="static_css")
app.mount("/static/js", StaticFiles(directory="web/html/js"), name="static_js")
app.mount(
"/static/images", StaticFiles(directory="web/html/images"), name="static_images"
)
# Add application middlewares.
app.add_middleware(AuthenticationMiddleware, backend=BasicAuthBackend())
app.add_middleware(SessionMiddleware, secret_key=session_secret)
# Add application routes.
def add_router(module):
app.include_router(module.router)
util.apply_all(APP_ROUTES, add_router)
# Initialize the database engine and ORM.
get_engine()
def child_exit(server, worker): # pragma: no cover
"""This function is required for gunicorn customization
of prometheus multiprocessing."""
multiprocess.mark_process_dead(worker.pid)
async def internal_server_error(request: Request, exc: Exception) -> Response:
"""
Catch all uncaught Exceptions thrown in a route.
:param request: FastAPI Request
:return: Rendered 500.html template with status_code 500
"""
repo = aurweb.config.get("notifications", "gitlab-instance")
project = aurweb.config.get("notifications", "error-project")
token = aurweb.config.get("notifications", "error-token")
context = make_context(request, "Internal Server Error")
# Print out the exception via `traceback` and store the value
# into the `traceback` context variable.
tb_io = io.StringIO()
traceback.print_exc(file=tb_io)
tb = tb_io.getvalue()
context["traceback"] = tb
# Produce a SHA1 hash of the traceback string.
tb_hash = hashlib.sha1(tb.encode()).hexdigest()
tb_id = tb_hash[:7]
redis = redis_connection()
key = f"tb:{tb_hash}"
retval = redis.get(key)
if not retval:
# Expire in one hour; this is just done to make sure we
# don't infinitely store these values, but reduce the number
# of automated reports (notification below). At this time of
# writing, unexpected exceptions are not common, thus this
# will not produce a large memory footprint in redis.
pipe = redis.pipeline()
pipe.set(key, tb)
pipe.expire(key, 86400) # One day.
pipe.execute()
# Send out notification about it.
if "set-me" not in (project, token):
proj = quote_plus(project)
endp = f"{repo}/api/v4/projects/{proj}/issues"
base = f"{request.url.scheme}://{request.url.netloc}"
title = f"Traceback [{tb_id}]: {base}{request.url.path}"
desc = [
"DISCLAIMER",
"----------",
"**This issue is confidential** and should be sanitized "
"before sharing with users or developers. Please ensure "
"you've completed the following tasks:",
"- [ ] I have removed any sensitive data and "
"the description history.",
"",
"Exception Details",
"-----------------",
f"- Route: `{request.url.path}`",
f"- User: `{request.user.Username}`",
f"- Email: `{request.user.Email}`",
]
# Add method-specific information to the description.
if request.method.lower() == "get":
# get
if request.url.query:
desc = desc + [f"- Query: `{request.url.query}`"]
desc += ["", f"```{tb}```"]
else:
# post
form_data = str(dict(request.state.form_data))
desc = desc + [f"- Data: `{form_data}`"] + ["", f"```{tb}```"]
headers = {"Authorization": f"Bearer {token}"}
data = {
"title": title,
"description": "\n".join(desc),
"labels": ["triage"],
"confidential": True,
}
logger.info(endp)
resp = requests.post(endp, json=data, headers=headers)
if resp.status_code != http.HTTPStatus.CREATED:
logger.error(f"Unable to report exception to {repo}: {resp.text}")
else:
logger.warning(
"Unable to report an exception found due to "
"unset notifications.error-{{project,token}}"
)
# Log details about the exception traceback.
logger.error(f"FATAL[{tb_id}]: An unexpected exception has occurred.")
logger.error(tb)
else:
retval = retval.decode()
return render_template(
request,
"errors/500.html",
context,
status_code=http.HTTPStatus.INTERNAL_SERVER_ERROR,
)
@app.exception_handler(StarletteHTTPException)
async def http_exception_handler(request: Request, exc: HTTPException) -> Response:
"""Handle an HTTPException thrown in a route."""
phrase = http.HTTPStatus(exc.status_code).phrase
context = make_context(request, phrase)
context["exc"] = exc
context["phrase"] = phrase
# Additional context for some exceptions.
if exc.status_code == http.HTTPStatus.NOT_FOUND:
tokens = request.url.path.split("/")
matches = re.match("^([a-z0-9][a-z0-9.+_-]*?)(\\.git)?$", tokens[1])
if matches:
try:
pkgbase = get_pkg_or_base(matches.group(1))
context = pkgbaseutil.make_context(request, pkgbase)
except HTTPException:
pass
try:
return render_template(
request, f"errors/{exc.status_code}.html", context, exc.status_code
)
except TemplateNotFound:
return render_template(request, "errors/detail.html", context, exc.status_code)
@app.middleware("http")
async def add_security_headers(request: Request, call_next: typing.Callable):
"""This middleware adds the CSP, XCTO, XFO and RP security
headers to the HTTP response associated with request.
CSP: Content-Security-Policy
XCTO: X-Content-Type-Options
RP: Referrer-Policy
XFO: X-Frame-Options
"""
try:
response = await util.error_or_result(call_next, request)
except Exception as exc:
return await internal_server_error(request, exc)
# Add CSP header.
nonce = request.user.nonce
csp = "default-src 'self'; "
# swagger-ui needs access to cdn.jsdelivr.net javascript
script_hosts = ["cdn.jsdelivr.net"]
csp += f"script-src 'self' 'unsafe-inline' 'nonce-{nonce}' " + " ".join(
script_hosts
)
# swagger-ui needs access to cdn.jsdelivr.net css
css_hosts = ["cdn.jsdelivr.net"]
csp += "; style-src 'self' 'unsafe-inline' " + " ".join(css_hosts)
response.headers["Content-Security-Policy"] = csp
# Add XTCO header.
xcto = "nosniff"
response.headers["X-Content-Type-Options"] = xcto
# Add Referrer Policy header.
rp = "same-origin"
response.headers["Referrer-Policy"] = rp
# Add X-Frame-Options header.
xfo = "SAMEORIGIN"
response.headers["X-Frame-Options"] = xfo
return response
@app.middleware("http")
async def check_terms_of_service(request: Request, call_next: typing.Callable):
"""This middleware function redirects authenticated users if they
have any outstanding Terms to agree to."""
if request.user.is_authenticated() and request.url.path != "/tos":
unaccepted = (
query(Term)
.join(AcceptedTerm)
.filter(
or_(
AcceptedTerm.UsersID != request.user.ID,
and_(
AcceptedTerm.UsersID == request.user.ID,
AcceptedTerm.TermsID == Term.ID,
AcceptedTerm.Revision < Term.Revision,
),
)
)
)
if query(Term).count() > unaccepted.count():
return RedirectResponse("/tos", status_code=int(http.HTTPStatus.SEE_OTHER))
return await util.error_or_result(call_next, request)
@app.middleware("http")
async def id_redirect_middleware(request: Request, call_next: typing.Callable):
id = request.query_params.get("id")
if id is not None:
# Preserve query string.
qs = []
for k, v in request.query_params.items():
if k != "id":
qs.append(f"{k}={quote_plus(str(v))}")
qs = str() if not qs else "?" + "&".join(qs)
path = request.url.path.rstrip("/")
return RedirectResponse(f"{path}/{id}{qs}")
return await util.error_or_result(call_next, request)