libretime/analyzer/libretime_analyzer/status_reporter.py

228 lines
8.6 KiB
Python

import collections
import json
import logging
import pickle
import queue
import threading
import time
from urllib.parse import urlparse
import requests
from requests.exceptions import HTTPError
logger = logging.getLogger(__name__)
class PicklableHttpRequest:
def __init__(self, method, url, api_key, data):
self.method = method
self.url = url
self.api_key = api_key
self.data = data
def create_request(self):
return requests.Request(
method=self.method,
url=self.url,
data=self.data,
auth=requests.auth.HTTPBasicAuth(self.api_key, ""),
)
def process_http_requests(ipc_queue, http_retry_queue_path):
"""Runs in a separate thread and performs all the HTTP requests where we're
reporting extracted audio file metadata or errors back to the Airtime web application.
This process also checks every 5 seconds if there's failed HTTP requests that we
need to retry. We retry failed HTTP requests so that we don't lose uploads if the
web server is temporarily down.
"""
# Store any failed requests (eg. due to web server errors or downtime) to be
# retried later:
retry_queue = collections.deque()
shutdown = False
# Unpickle retry_queue from disk so that we won't have lost any uploads
# if airtime_analyzer is shut down while the web server is down or unreachable,
# and there were failed HTTP requests pending, waiting to be retried.
try:
with open(http_retry_queue_path, "rb") as pickle_file:
retry_queue = pickle.load(pickle_file)
except OSError as exception:
if exception.errno != 2:
raise exception
except Exception:
# If we fail to unpickle a saved queue of failed HTTP requests, then we'll just log an error
# and continue because those HTTP requests are lost anyways. The pickled file will be
# overwritten the next time the analyzer is shut down too.
logger.error("Failed to unpickle %s. Continuing...", http_retry_queue_path)
while True:
try:
while not shutdown:
try:
request = ipc_queue.get(block=True, timeout=5)
if (
isinstance(request, str) and request == "shutdown"
): # Bit of a cheat
shutdown = True
break
except queue.Empty:
request = None
# If there's no new HTTP request we need to execute, let's check our "retry
# queue" and see if there's any failed HTTP requests we can retry:
if request:
send_http_request(request, retry_queue)
else:
# Using a for loop instead of while so we only iterate over all the requests once!
for _ in range(len(retry_queue)):
request = retry_queue.popleft()
send_http_request(request, retry_queue)
logger.info("Shutting down status_reporter")
# Pickle retry_queue to disk so that we don't lose uploads if we're shut down while
# while the web server is down or unreachable.
with open(http_retry_queue_path, "wb") as pickle_file:
pickle.dump(retry_queue, pickle_file)
return
except (
Exception
) as exception: # Terrible top-level exception handler to prevent the thread from dying, just in case.
if shutdown:
return
logger.exception("Unhandled exception in StatusReporter %s", exception)
logger.info("Restarting StatusReporter thread")
time.sleep(2) # Throttle it
def send_http_request(picklable_request: PicklableHttpRequest, retry_queue):
try:
bare_request = picklable_request.create_request()
session = requests.Session()
prepared_request = session.prepare_request(bare_request)
resp = session.send(
prepared_request, timeout=StatusReporter._HTTP_REQUEST_TIMEOUT
)
resp.raise_for_status() # Raise an exception if there was an http error code returned
logger.info("HTTP request sent successfully.")
except requests.exceptions.HTTPError as exception:
if exception.response.status_code == 422:
# Do no retry the request if there was a metadata validation error
logger.exception(
f"HTTP request failed due to an HTTP exception: {exception}"
)
else:
# The request failed with an error 500 probably, so let's check if Airtime and/or
# the web server are broken. If not, then our request was probably causing an
# error 500 in the media API (ie. a bug), so there's no point in retrying it.
logger.exception("HTTP request failed: %s", exception)
parsed_url = urlparse(exception.response.request.url)
if is_web_server_broken(parsed_url.scheme + "://" + parsed_url.netloc):
# If the web server is having problems, retry the request later:
retry_queue.append(picklable_request)
# Otherwise, if the request was bad, the request is never retried.
# You will have to find these bad requests in logs or you'll be
# notified by sentry.
except requests.exceptions.ConnectionError as exception:
logger.exception(
"HTTP request failed due to a connection error, retrying later: %s",
exception,
)
retry_queue.append(picklable_request) # Retry it later
except Exception as exception:
logger.exception("HTTP request failed with unhandled exception. %s", exception)
# Don't put the request into the retry queue, just give up on this one.
# I'm doing this to protect against us getting some pathological request
# that breaks our code. I don't want us pickling data that potentially
# breaks airtime_analyzer.
def is_web_server_broken(url):
"""Do a naive test to check if the web server we're trying to access is down.
We use this to try to differentiate between error 500s that are coming
from (for example) a bug in the Airtime Media REST API and error 500s
caused by Airtime or the webserver itself being broken temporarily.
"""
try:
test_req = requests.get(url)
test_req.raise_for_status()
except HTTPError:
return True
return False
class StatusReporter:
"""Reports the extracted audio file metadata and job status back to the
Airtime web application.
"""
_HTTP_REQUEST_TIMEOUT = 30
_ipc_queue = queue.Queue()
_http_thread = None
@classmethod
def start_thread(cls, http_retry_queue_path):
StatusReporter._http_thread = threading.Thread(
target=process_http_requests,
args=(StatusReporter._ipc_queue, http_retry_queue_path),
)
StatusReporter._http_thread.start()
@classmethod
def stop_thread(cls):
logger.info("Terminating status_reporter process")
StatusReporter._ipc_queue.put("shutdown")
StatusReporter._http_thread.join()
@classmethod
def _send_http_request(cls, request):
StatusReporter._ipc_queue.put(request)
@classmethod
def report_success(
cls,
callback_url: str,
callback_api_key: str,
metadata: dict,
):
"""Report the extracted metadata and status of the successfully imported file
to the callback URL (which should be the Airtime File Upload API)
"""
put_payload = json.dumps(metadata)
StatusReporter._send_http_request(
PicklableHttpRequest(
method="PUT",
url=callback_url,
api_key=callback_api_key,
data=put_payload,
)
)
@classmethod
def report_failure(
cls,
callback_url,
callback_api_key,
import_status: int,
reason,
):
logger.debug("Reporting import failure to Airtime REST API...")
audio_metadata = {}
audio_metadata["import_status"] = import_status
audio_metadata["comment"] = reason # hack attack
put_payload = json.dumps(audio_metadata)
# logger.debug("sending http put with payload: %s", put_payload)
StatusReporter._send_http_request(
PicklableHttpRequest(
method="PUT",
url=callback_url,
api_key=callback_api_key,
data=put_payload,
)
)