horneds/knocker repository overview

⁠Knocker

The Knocker Service is a simple ready-to-deploy service to retry HTTP calls.

Let's imagine that your application is making HTTP webhook calls when something happens. And you need to be really sure that the webhooks reach their destinations. In this case you may add additional logic to your app, setup some kind of queue to retry the failed requests or let the Knocker do everything for you automatically.

The features:

• Working as a web-service
• Usable Interface to make HTTP calls
• Configurable (timeouts, retry-policies)
• Callbacks for failed requests and etc
• Sentry⁠ Integration

Public version is available here: https://knock.horneds.com⁠

⁠Getting started

There is a docker container horneds/knocker available. Example run (locally):

    docker run --rm -p 0.0.0.0:8000:8000 horneds/knocker

Service will be available http://localhost:8000⁠

⁠Making a requests

Basically, all you need to make requests with Knocker is to change URL HOST to your Knocker Instance and put the original one into Knocker-Host header.

Let's imagine you have a Knockout Service is running behind the URL: https://knock.horneds.com⁠ and you want to make a request to https://target-server.com/webhook/?some-params=12⁠

Request:

POST /webhook/?some-params=12 HTTP/1.1
Host: knock.horneds.com
Content-Type: application/json
Knocker-Host: target-server.com
Knocker-Timeout: 15.0
Knocker-Retries: 5

"SOME REQUEST BODY"

Response:

HTTP/1.1 200 OK
Connection: keep-alive
Content-Encoding: gzip
Content-Type: application/json
Date: Tue, 02 Jun 2020 15:10:37 GMT
Transfer-Encoding: chunked

{
    "config": {
        "backoff_factor": 0.5,
        "callback": null,
        "retries": 5,
        "timeout": 15.0,
        "id": "4498279872/4494502784",
    },
    "status": true
}

Knocker will attempt to make a POST request to https://target-server.com/webhook/?some-params=12 with the given request's body. It will retry the request 5 times after fails (response status 4**, 5**)

⁠Configuration per a request

Requests parameters are passed through HTTP headers:

All other headers which begin from knocker- prefix won't be sent to a target host but will be sent to a callback.

⁠Callbacks

If all Knocker's attempts to make a given request were failed and callback url was given then Knocker will make a request to the given callback URL with params:

POST /your-callback-url
Host: origin-server.com
Content-Type: application/json

{
    "config": {
        "id": "ID", // Request ID
        // ... Request Config
    },
    "method": "GET", // Request Method
    "url": "https://target-server.com/webhook/?some-params=12 HTTP/1.1", // The URL is failed
    "status_code": 403, // Latest failed status code
}

⁠Global Configuration

Knocker Service setups with the ENVIRONMENT variables:

⁠Bug tracker

If you have any suggestions, bug reports or annoyances please report them to the issue tracker at https://github.com/klen/knocker/issues⁠

⁠Contributing

Development of The Knocker happens at: https://github.com/klen/knocker⁠

⁠Contributors

• Kirill Klenov⁠

⁠License

Licensed under a MIT license (See LICENSE⁠)