R1D41 Debugging Webhooks with Flask and Ngrok
Webhooks are the magic glue that allows you to integrate many different applications together. Essentially a webhook sends a JSON payload of data to some pre-defined endpoint from one system to another.
When webhooks go wrong
While they are great, and usually easy to get started with, it can be a bit tough to debug them when things are not quite working as expected. Recently, there have been some issues with webhooks at CircleCI. There are many different failure modes since there are many different combinations of systems that are possibly involved.The key questions to ask when debugging webhooks are:
- Was it sent?
- What did the payload look like?
- What payload does the receiving system expect?
Answering question #3 will be left as an exercise to the reader since there is no way to have a one size fits all answer. This will depend strictly on the receiving system.
Using the Tool
The flask app is about as simple as it can get.# app.pyThis will “pretty print” the JSON payload to console. You can start this up with:from flask import Flask, request import pprint
app = Flask(name)
@app.route(’/’, methods=[‘GET’, ‘POST’]) def index(): if request.method == ‘GET’: return ‘Send me a POST’ else: pprint.pprint(request.json) return ‘Check Console’
FLASK_APP=app.py && flask run
The app will be running on port 5000 locally. Then you can use ngrok to forward traffic from the internet to any local port on your computer.
Once you have downloaded and installed ngrok you can start it up with:
./ngrok http 5000
This will start up ngrok and start forwarding traffic to your local computer. In the terminal you should see a screen like this:
You can then use the “Forwarding” address anywhere on the web to send requests back to your local computer.
In our specific example, I would add the following section to my config.yml
file in CircleCI in order to see the webhooks being sent from CircleCI.
notify: webhooks: - url: https://a6f2fcd7.ngrok.io
With the app running, I can now receive and inspect webhooks locally in my console.
* Serving Flask app "app" * Running on https://127.0.0.1:5000/ (Press CTRL+C to quit) {u'payload': {u'all_commit_details': [{u'author_date': u'2018-03-10T10:24:08-08:00', u'author_email': u'[email protected]', u'author_login': u'levlaz', u'author_name': u'Lev Lazinskiy', u'body': u'', u'branch': u'webhooks', u'commit': u'4ee0d32afb7ff5e821593366616a660c9720b70e', u'commit_url': u'https://github.com/levlaz/sandbox/commit/4ee0d32afb7ff5e821593366616a660c9720b70e', u'committer_date': u'2018-03-10T10:24:08-08:00', u'committer_email': u'[email protected]', u'committer_login': u'levlaz', u'committer_name': u'Lev Lazinskiy', u'subject': u'test hooks'}], u'author_date': u'2018-03-10T10:24:08-08:00', u'author_email': u'[email protected]', u'author_name': u'Lev Lazinskiy', u'body': u'', u'branch': u'webhooks', u'build_num': 92, u'build_parameters': None, u'build_time_millis': 1419, u'build_url': u'https://circleci.com/gh/levlaz/sandbox/92', u'canceled': False, u'canceler': None, u'circle_yml': {u'string': u"version: 2\njobs:\n build:\n working_directory: ~/sandbox\n docker:\n - image: circleci/python\n steps:\n - checkout\n - run:\n name: Do Nothing\n command: |\n echo 'Hello!'\n\nnotify:\n webhooks:\n - url: https://7eab6a64.ngrok.io\n"}, u'committer_date': u'2018-03-10T10:24:08-08:00', u'committer_email': u'[email protected]', u'committer_name': u'Lev Lazinskiy', u'compare': u'https://github.com/levlaz/sandbox/commit/4ee0d32afb7f', u'dont_build': None, u'fail_reason': None, u'failed': False, u'has_artifacts': True, u'infrastructure_fail': False, u'is_first_green_build': False, u'job_name': None, u'lifecycle': u'finished', u'messages': [], u'no_dependency_cache': False, u'node': None, u'oss': True, u'outcome': u'success', u'owners': [u'levlaz'], u'parallel': 1, u'picard': {u'build_agent': {u'image': None, u'properties': {u'build_agent': u'0.0.4732-ed067b9', u'executor': u'docker'}}, u'executor': u'docker', u'resource_class': {u'class': u'medium', u'cpu': 2.0, u'ram': 4096}}, u'platform': u'2.0', u'previous': {u'build_num': 91, u'build_time_millis': 1919, u'status': u'success'}, u'previous_successful_build': {u'build_num': 91, u'build_time_millis': 1919, u'status': u'success'}, u'pull_requests': [], u'queued_at': u'2018-03-10T18:29:32.788Z', u'reponame': u'sandbox', u'retries': None, u'retry_of': 91, u'ssh_disabled': True, u'ssh_users': [], u'start_time': u'2018-03-10T18:29:34.680Z', u'status': u'success', u'steps': [{u'actions': [{u'allocation_id': u'5aa4240cc9e77c00013bc7e5-0-build/4C67169D', u'background': False, u'bash_command': None, u'canceled': None, u'continue': None, u'end_time': u'2018-03-10T18:29:35.593Z', u'exit_code': None, u'failed': None, u'has_output': True, u'index': 0, u'infrastructure_fail': None, u'insignificant': False, u'name': u'Spin up Environment', u'output_url': u'https://circle-production-action-output.s3.amazonaws.com/64c10c100094c9d1e0424aa5-levlaz-sandbox-0-0?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20180310T182936Z&X-Amz-SignedHeaders=host&X-Amz-Expires=431999&X-Amz-Credential=AKIAIQ65EYQDTMSJK2DQ%2F20180310%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=db22e946ba891c0c89503a3b0f5de635be92e6802e3941db778a198658f0afaa', u'parallel': True, u'run_time_millis': 877, u'start_time': u'2018-03-10T18:29:34.716Z', u'status': u'success', u'step': 0, u'timedout': None, u'truncated': False, u'type': u'test'}], u'name': u'Spin up Environment'}, {u'actions': [{u'allocation_id': u'5aa4240cc9e77c00013bc7e5-0-build/4C67169D', u'background': False, u'bash_command': u'#!/bin/sh\nset -e\n\n# Workaround old docker images with incorrect $HOME\n# check https://github.com/docker/docker/issues/2968 for details\nif [ "${HOME}" = "/" ]\nthen\n export HOME=$(getent passwd $(id -un) | cut -d: -f6)\nfi\n\nmkdir -p ~/.ssh\n\necho \'github.com ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==\nbitbucket.org ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAubiN81eDcafrgMeLzaFPsw2kNvEcqTKl/VqLat/MaB33pZy0y3rJZtnqwR2qOOvbwKZYKiEO1O6VqNEBxKvJJelCq0dTXWT5pbO2gDXC6h6QDXCaHo6pOHGPUy+YBaGQRGuSusMEASYiWunYN0vCAI8QaXnWMXNMdFP3jHAJH0eDsoiGnLPBlBp4TNm6rYI74nMzgz3B9IikW4WVK+dc8KZJZWYjAuORU3jc1c/NPskD2ASinf8v3xnfXeukU0sJ5N6m5E8VLjObPEO+mN2t/FZTMZLiFqPWc/ALSqnMnnhwrNi2rbfg/rd/IpL8Le3pSBne8+seeFVBoGqzHM9yXw==\n\' >> ~/.ssh/known_hosts\n\n(umask 077; touch ~/.ssh/id_rsa)\nchmod 0600 ~/.ssh/id_rsa\n(cat < ~/.ssh/id_rsa\n$CHECKOUT_KEY\nEOF\n)\n\n# use git+ssh instead ofhttps\ngit config --global url."ssh://[email protected]".insteadOf "https://github.com" || true\n\nif [ -e /home/circleci/sandbox/.git ]\nthen\n cd /home/circleci/sandbox\n git remote set-url origin "$CIRCLE_REPOSITORY_URL" || true\nelse\n mkdir -p /home/circleci/sandbox\n cd /home/circleci/sandbox\n git clone "$CIRCLE_REPOSITORY_URL" .\nfi\n\nif [ -n "$CIRCLE_TAG" ]\nthen\n git fetch --force origin "refs/tags/${CIRCLE_TAG}"\nelse\n git fetch --force origin "webhooks:remotes/origin/webhooks"\nfi\n\n\nif [ -n "$CIRCLE_TAG" ]\nthen\n git reset --hard "$CIRCLE_SHA1"\n git checkout -q "$CIRCLE_TAG"\nelif [ -n "$CIRCLE_BRANCH"]\nthen\n git reset --hard "$CIRCLE_SHA1"\n git checkout -q -B "$CIRCLE_BRANCH"\nfi\n\ngit reset --hard"$CIRCLE_SHA1"', u'canceled': None, u'continue': None, u'end_time': u'2018-03-10T18:29:36.075Z', u'exit_code': 0, u'failed': None, u'has_output': True, u'index': 0, u'infrastructure_fail': None, u'insignificant': False, u'name': u'Checkout code', u'parallel': True, u'run_time_millis': 415, u'start_time': u'2018-03-10T18:29:35.660Z', u'status': u'success', u'step': 101, u'timedout': None, u'truncated': False, u'type': u'test'}], u'name': u'Checkout code'}, {u'actions': [{u'allocation_id': u'5aa4240cc9e77c00013bc7e5-0-build/4C67169D', u'background': False, u'bash_command': u"#!/bin/bash -eo pipefail\necho 'Hello!'\n", u'canceled': None, u'continue': None, u'end_time': u'2018-03-10T18:29:36.093Z', u'exit_code': 0, u'failed': None, u'has_output': True, u'index': 0, u'infrastructure_fail': None, u'insignificant': False, u'name': u'Do Nothing', u'parallel': True, u'run_time_millis': 13, u'start_time': u'2018-03-10T18:29:36.080Z', u'status': u'success', u'step': 102, u'timedout': None, u'truncated': False, u'type': u'test'}], u'name': u'Do Nothing'}], u'stop_time': u'2018-03-10T18:29:36.099Z', u'subject': u'test hooks', u'timedout': False, u'usage_queued_at': u'2018-03-10T18:29:32.763Z', u'user': {u'avatar_url': u'https://avatars2.githubusercontent.com/u/7981032?v=4', u'id': 7981032, u'is_user': True, u'login': u'levlaz', u'name': u'Lev Lazinskiy', u'vcs_type': u'github'}, u'username': u'levlaz', u'vcs_revision': u'4ee0d32afb7ff5e821593366616a660c9720b70e', u'vcs_tag': None, u'vcs_type': u'github', u'vcs_url': u'https://github.com/levlaz/sandbox', u'why': u'retry'}} 127.0.0.1 - - [10/Mar/2018 10:29:36] "POST / HTTP/1.1" 200 -
Thank you for reading! Share your thoughts with me on mastodon or via email.
Check out some more stuff to read down below.
Most popular posts this month
- Dagger Feels Like Magic
- Setting up ANTLR4 on Windows
- SQLite DB Migrations with PRAGMA user_version
- 20 Years of Ubuntu
- видно по глазам - you can see it in the eyes
Recent Favorite Blog Posts
This is a collection of the last 8 posts that I bookmarked.
- Serendipity from Armin Ronacher's Thoughts and Writings
- Andrea Veri: GNOME Infrastructure migration to AWS from Planet GNOME
- A Whale of a Time from https://popagandhi.com/
- Pluralistic: You should be using an RSS reader (16 Oct 2024) from Pluralistic: Daily links from Cory Doctorow
- Sahil Dhiman: 25, A Quarter of a Century Later from Planet Debian
- Reflections on Palantir from Nabeel S. Qureshi
- Reading Old Posts from Kev Quirk
- Capture less than you create from David Heinemeier Hansson
Articles from blogs I follow around the net
Script Doctoring
I’ve been having a number of communications problems in my interactions with my doctors at Kaiser lately, and it’s becoming one of those things where the burden and onus entirely is placed upon me to sort out, and that’s exhausting for the actually autist…
via Bix Dot Blog October 22, 2024Blockchain company Forte acquires games studios, demands secrecy, shuts them down
Sometime in 2023, blockchain firm Forte acquired game studios Phoenix Labs and Rumble Games. However, it would be a year before this came to light, because according to a report from Game Developer, Forte demanded secrecy from employ…
via Web3 is Going Just Great October 22, 2024Initial explorations of Anthropic's new Computer Use capability
Two big announcements from Anthropic today: a new Claude 3.5 Sonnet model and a new API mode that they are calling computer use. (They also pre-announced Haiku 3.5, but that's not available yet so I'm ignoring it until I can try it out myself.) Comp…
via Simon Willison's Weblog: Entries October 22, 2024Generated by openring