captainhook

A generic webhook endpoint that runs scripts based on the URL called

This tool was built as part of a CI orchestration process, to be called when Docker trusted builds finish. It explicitly ignores the posted data from the webhook because that would be insecure, which is bad.

Quick Start

Install captainhook

go get github.com/bketelsen/captainhook

Create the `configdir`

mkdir ~/captainhook

Add a script

{
    "scripts": [
        {
            "command": "ls",
            "args": [
                "-l",
                "-a"
            ]
        },
        {
            "command": "echo",
            "args": [
		    "hello"
		    ]
        }
    ]
}

Name this script endpoint1.json

Start the service

captainhook -configdir ~/captainhook

Test using curl

curl -X POST http://localhost:8080/endpoint1

Configure calling webhooks

Each script you create in the configdir will be executed when the corresponding endpoint is called.

If you have a script called deployBigApp.json you would trigger it by posting to http://your.captainhook.url/deployBigApp.

The scripts in the json file are executed sequentially, and the output is logged and returned to the caller in the response, which always has an HTTP status code of 200 (OK) even if your scripts didn't work. This is intentional, to avoid causing errors in external services like Docker or Github, which might not like you returning statuses other than 200 (OK).

Accessing the Request POST Body

You'll sometimes need to access the POST data of the request for information such as a callback URL. You can pass the raw POST data to a script by adding {{POST}} to the script arguments.

{
    "scripts": [
        {
            "command": "echo",
            "args": [
            "{{POST}}"
            ]
        }
    ]
}

Limiting access for webhooks

You can limit who can call your webhooks by specifying "allowedNetworks" in the json config.

{
    "scripts": [
        {
            "command": "echo"
        }
    ],
    "allowedNetworks": [
        "10.0.0.0/8",
        "127.0.0.1/32"
    ]
}

This would allow your hook to be called from the 10.0.0.0/8 network, or from localhost.

Supporting proxy headers for client IP

Only enable proxy support if you are on a trusted network behind a reverse proxy. End-users with direct network access can subvert the allowedNetworks restriction if proxy support is on.

captainhook -configdir ~/captainhook -enable-proxy -proxy-header X-Forwarded-For

Docker

docker pull bketelsen/captainhook
mkdir /some/local/config
$EDITOR /some/local/config/myhook.json
docker run -d -v /some/local/config:/config bketelsen/captainhook

Install