Implement fifo hooks

This commit is contained in:
Théophile Bastian 2022-04-15 18:31:39 +02:00
parent 877ff2bef0
commit c86a4bb1b9
3 changed files with 105 additions and 0 deletions

4
config.sample.yml Normal file
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fifo_hooks:
test_repo:
secret: very_secret # same as given to gitea
fifo_path: /var/run/test_repo

68
gitea_hooks/app.py Normal file
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import typing as t
import hmac
import hashlib
import json
from collections import defaultdict
from flask import Flask, request, abort
from .conf import Configuration
config = Configuration()
app = Flask(__name__)
def webhook_receiver(hook_type):
if hook_type not in config.raw:
raise Exception(f"Badly configured route: no conf of type {hook_type}")
relevant_hooks = config.raw[hook_type]
def inner(func):
def wrapped(hook_name: str):
if request.content_length is None or request.content_length > 32000:
abort(400)
if request.content_type != "application/json":
return "Expected json", 415
if hook_name not in relevant_hooks:
abort(404)
hook_conf = relevant_hooks[hook_name]
raw_payload: bytes = request.get_data(cache=False)
provided_sig: str = request.headers["X-Gitea-Signature"]
computed_sig = hmac.new(
hook_conf["secret"].encode("utf-8"), raw_payload, hashlib.sha256
).hexdigest()
if not hmac.compare_digest(provided_sig, computed_sig):
abort(403)
try:
payload = json.loads(raw_payload)
except json.JSONDecodeError:
return "Bad JSON", 400
return func(payload, hook_name, hook_conf)
return wrapped
return inner
@app.route("/")
def root() -> t.Tuple[str, int]:
"""Root web handler -- pointless in this case"""
return "Not supported.", 400
@app.route("/fifo/<string:hook_name>", methods=["POST"])
@webhook_receiver("fifo_hooks")
def fifo_hooks(payload, hook_name, hook_conf):
"""Fifo web handler -- write 1 to a unix fifo"""
try:
with open(hook_conf["fifo_path"], "w") as fifo:
fifo.write("1")
except FileNotFoundError:
return "No such fifo", 500
except PermissionError:
return "Permission denied on FIFO", 500
return "OK", 200

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gitea_hooks/conf.py Normal file
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import yaml
class BadConfig(Exception):
"""Raised when the configuration is incorrect"""
class Configuration:
"""Parses the configuration file, and caches it.
The configuration is a YAML file.
"""
def __init__(self):
try:
with open("./config.yml", "r") as handle:
self.raw = yaml.safe_load(handle)
except yaml.YAMLError as exn:
raise BadConfig("Cannot parse yaml") from exn
except FileNotFoundError as exn:
raise BadConfig("Configuration file not found") from exn
except PermissionError as exn:
raise BadConfig("Configuration file not readable") from exn
self._healthcheck()
def _healthcheck(self):
"""Checks that the configuration is ok"""
if "fifo_hooks" not in self.raw:
raise BadConfig("No `fifo_hooks`")
for hook, data in self.raw["fifo_hooks"].items():
for mandatory in ("secret", "fifo_path"):
if mandatory not in data:
raise BadConfig("Fifo hook {}: no `{}`".format(hook, mandatory))