specs/forgehook/README.md

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# Webhook endpoints

This repository contains documentation and tests about running webhook endpoints as part of a [forge suite](https://thunix.net/~southerntofu/forge) setup. There are tests for CLI webhook validation programs (such as [whck](https://tildegit.org/forge/whck)), as well as for web validation programs (HTTP endpoints such as [endpoints.php](https://tildegit.org/forge/endpoints.php)). A certain number of conventions (environment variables and folder structure) should make it "just work" for different kinds of setups including shared hosts with unprivileged accounts. **For setup information, please head over to the [Setup section](#setup).**

Below, you will find specifications for the [CLI](#cli) and [Web](#web) programs. For the reference of supported webhook sources and their respective property, please read the [Sources section](#sources)

# Web interface {#web}

A webhook HTTP endpoint is a web validator that receives requests from remote services, and validates them using a CLI validator as described in the [Command-line interface section](#cli). A web validator implements support for various [Sources](#sources) to extract the claimed secret as well as the webhook content. For the moment, two different verification schemes (used by several sources) are supported:

- `hmac-sha256` header signature: used by Github and Gitea to sign the body (JSON payload)
- `token` header: used by Gitlab without signatures, so the body (payload) is ignored

The web validator returns HTTP status code 200 when validation succeeded, or any other exit code if it fails. In the future, error codes could be standardized.

## Conventions

In order to facilitate deployment in varied setups, each web validator respects the following conventions:

- returns HTTP code 200 when validation succeeded, or any other exit code if it fails. In the future, error codes could be standardized
- the CLI validator used to validate incoming webhooks is generated from the following possibilities, in order of preference:
  - from the `WHCK` environment variable (automated tests)
  - from the `./bin/whck` program, which is not tracked in git (if you want to override whck from `PATH`)
  - from `whck` in the current `PATH` (for proper install)
- a `bin/server` script builds the web validator:
  - returning 0 upon success (or if the code doesn't require building) and outputting a complete path to the executable starting the program
  - any other exit code indicates failure
- a `spec` submodule contains this very repository ([forge/endpoints](https://tildegit.org/forge/endpoints))
- a `bin/test.sh` script starts the tests: ensures the spec submodule is cloned, and starts the `spec/test_web.sh` with the following arguments:
  - the full path to the executable (generated by `bin/server`)
  - (optional) the full path to `bin/whck` if it exists (user override), or the full path to `whck` from current `PATH`, or nothing if neither of those options matches
- the executable starts the web server on localhost, on a port which is configured, in this order of precedence:
  - by a `FORGEHOOKPORT` environment variable (used in tests)
  - by a first positional argument passed to the script (for manual use)

## Testing

**If you want to run tests for an existing implementation, please run the bin/test.sh script from the implementation's repository.**

**NOTE:** Running tests requires the bats testing framework. You can usually find it in your distro repositories. If not, head over to the [bats repository](https://github.com/bats-core/bats-core/).

The `test_web.sh` script is used for testing web validators (such as [endpoints.php](https://tildegit.org/forge/endpoints.php)). It takes two optional positional arguments:

- a path to a web validator executable (as defined in the Conventions section); if no argument is provided, the implementation's `bin/server` script will be executed to find a path to the executable; the `bin/server` script will be looked up on these paths, in order of precedence:
  - `bin/server`, relative to the directory from which you called the tests (eg. if you're running `specs/test_web.sh` from endpoints.php repository)
  - `../bin/server`, relative to the directory containing test_web.sh (eg. if you're running `./test_web.sh` from specs submodule in endpoints.php repository)
  - if no path was matched, the test suite fails to start
- a path to a CLI validator executable; if no argument is provided, the following paths will be attempted, in order of precedence:
  - the output of `whck/bin/cli`, relative to the current working dir (eg. calling `specs/test_web.sh` from endpoints.php repository)
  - the output of `../whck/bin/cli`, relative to the current working dir (eg. calling `./test_web.sh` from specs submodule in endpoints.php repository)
  - if no path was matched, the test suite fails to start

**To run tests, simply call bin/test.sh from your implementation repository**. If you call tests using `specs/test_web.sh` directly, it will assume you either want to test specific implementations (passed by arguments), or that you want to test the implementations in the parent repository. If you want the web endpoint tests to use the `whck` from `PATH`, please use the endpoint's `bin/test.sh` script.

**Note: to test that the test suites can be called from several folders using different kind of relative/absolute paths, use the `test_tests_web.sh` script.:**

# Sources

|    Name   |   Payload   |   Secret type   |   Secret location         |   Repo location       |
|:---------:|:-----------:|:---------------:|:-------------------------:|:---------------------:|
| Gitea     | JSON body   | hmac-sha256 sig | header:X_GITEA_SIGNATURE  | repository>html_url   |
| Github    | JSON body   | hmac-sha256 sig | header:X_HUB_SIGNATURE    | repository>html_url   |
| Gitlab    | JSON body   | token           | header:X_GITLAB_TOKEN     | project->git_http_url |

# Setup {#setup}

Now it gets tricky... In all cases you need some kind of shell account!
Talk about sudo, suid, please etc.

## Unprivileged user, web server running as user

## Unprivileged user, web server running as system account

## Privileged user (requires root)


# TODO

- reimplement calling forgehook-notify from endpoints.php
- add test to check it's actually called
- split READMEs separately for CLI and HTTP endpoint
- maybe have all specs/tests/READMEs (with forgebuild) in a single repo?
- make higher-level helper functions that can be shared across test files and implementation, for better consistency