Request Repeater

Simple Ruby Gem or Docker image to execute GET request on an endpoint (Request Repeater).

This is useful if you cannot do cron jobs in your application setup.

Just expose a certain route in your web application to execute the job (or to schedule background job) and tell request_repeeter to trigger GET requests on it.

Application can be executed as:

• :heavy_dollar_sign: Standalone Ruby gem application
• :whale: Docker image application

Standalone Ruby gem

Instalation

Add this line to your application's Gemfile:

gem 'request_repeater'

And then execute:

$ bundle

Or install it yourself as:

$ gem install request_repeater

Or install it yourself as:

$ gem install request_repeater

Usage

Single endpoint

Pass enviroment variable URL with location

# every second send request to http://localhost:3000/execute-something.html
$ URL=http://localhost:3000/execute-something.html bundle exec request_repeater

# ...or if you didn't use Bundler
$ URL=http://localhost:3000/execute-something.html request_repeater

Default timeout is 1000ms (1 second), if you need different timeout pass SLEEPFOR env variable:

# every two seconds send request to https://localhost:3000/maintenance?token=12345
$ URL=https://localhost:3000/maintenance?token=12345 SLEEPFOR=2000 bundle exec request_repeater

For authentication we recommend just to pass token as a query param, like: /maintenance?token=12345

Multiple endpoints

You need to pass URLS env variable with json in format:

{
  "urls": [
    {"url":"http://myserver/some-endpoint", "sleep":4000},
    {"url":"http://myserver/another-endpoint", "sleep":1200},
    {"url":"http://myserver/third-endpoint", "sleep":72000}
  ]
}

example:

$ URLS='{"urls": [{"url":"http://localhost/some-endpoint", "sleep":1200}, {"url":"http://localhost/another-endpoint","sleep":3000}]}' bundle exec request_repeater

URL and SLEEPFOR env variables are ignored when you provide URLS env variable

Docker Image Application

Usage

$ docker pull pobble/request_repeater

Single Endpoint

Specify URL env variable

$ docker run -e "URL=http://www.my-app.dot/execute-something.html" pobble/request_repeater

Default timeout is 1000ms (1 second), if you need different timeout pass SLEEPFOR env variable:

# 2 second timeout
$ docker run -e "SLEEPFOR=2000" -e "URL=http://www.my-app.dot/execute-something.html" pobble/request_repeater

To execute on localhost of image host:

$ docker run -e "SLEEPFOR=2000" -e "URL=http://localhost:3000/execute-something.html" --net="host" pobble/request_repeater

You want authentication ? How about passing token param:

$ docker run -e "URL=https://www.my-app.dot/execute-something.html?token=1234556"  pobble/request_repeater

docker-compose.yml example

---
version: '2'
services:
  nginx:
    image: quay.io/myorg/my-nginx-image
    ports:
      - "80:80"
  request_repeater:
    image: 'pobble/request_repeater'
    links:
      - nginx:nginx
    environment:
      URL: 'http://nginx/some-endpoint'
      SLEEPFOR: 7200

AWS Elastic Beanstalk Dockerrun.aws.json example

{
  "containerDefinitions": [
    {
      "name": "nginx",
      "image": "........",
      "portMappings": [
        {
          "hostPort": 80,
          "containerPort": 80
        }
      ],
    },
    {
      "name": "request_repeater",
      "image": "pobble/request_repeater",
      "essential": true,
      "memory": 150,
      "links": [ "nginx" ],
      "environment": [
        {
          "name": "URL",
          "value": "http://nginx/some-endpoint"
        }
      ]
    }
  ]
}

Multiple endpoints

You need to pass URLS env variable with JSON in format:

{
  "urls": [
    {"url":"http://myserver/some-endpoint", "sleep":4000},
    {"url":"http://myserver/another-endpoint", "sleep":1200},
    {"url":"http://myserver/third-endpoint", "sleep":72000}
  ]
}

$ docker run -e 'URLS={"urls": [{"url":"http://localhost/some-endpoint", "sleep":1200}, {"url":"http://localhost/another-endpoint","sleep":3000}]}' --net="host" pobble/request_repeater

URL and SLEEPFOR env variables are ignored when you provide URLS env variable

Docker Composer example

docker-compose.yml:

---
version: '2'
services:
  nginx:
    image: quay.io/myorg/my-nginx-image
    ports:
      - "80:80"
  request_repeater:
    image: 'pobble/request_repeater'
    links:
      - nginx:nginx
    environment:
      URLS: '{"urls": [{"url":"http://nginx/some-endpoint", "sleep":1200},
{"url":"http://nginx/another-endpoint","sleep":7200}]}'

AWS Elastic Beanstalk Dockerrun.aws.json example usage

Dockerrun.aws.json:

{
  "containerDefinitions": [
    {
      "name": "nginx",
      "image": "........",
      "portMappings": [
        {
          "hostPort": 80,
          "containerPort": 80
        }
      ],
    },
    {
      "name": "request_repeater",
      "image": "pobble/request_repeater",
      "essential": true,
      "memory": 150,
      "links": [ "nginx" ],
      "environment": [
        {
          "name": "URLS",
          "value":"{\"urls\":[{\"url\":\"http://nginx/some-endpoint\",\"sleep\":1300},{\"url\":\"http://nginx/other-endpoint\",\"sleep\":1200000}]}"

        }
      ]
    }
  ]
}

Kill the container

$ docker kill $(docker ps | grep request_repeater | awk "{print \$1}")

# sudo version
$ sudo docker kill $(sudo docker ps | grep request_repeater | awk "{print \$1}")

Minimum Sleeptime

In order to avoid docker container / gem to use all CPU resources there is a minimum sleep time implementend set to 500 miliseconds. If you need to use this image without this limit provide one more extra enviroment variable MINIMUMSLEEP:

$ URL=https://www.my-app.dot/execute-something.html SLEEPFOR=100 MINIMUMSLEEP=0 bundle exec request_repeater

$ docker run -e "SLEEPFOR=300" -e 'MINIMUMSLEEP=300' -e "URL=http://www.my-app.dot/execute-something.html" pobble/request_repeater # 300 ms

$ docker run -e "SLEEPFOR=0" -e 'MINIMUMSLEEP=0' -e "URL=http://www.my-app.dot/execute-something.html" pobble/request_repeater # no limit

Alternatives

This Ruby Gem (and Docker image) is attempt to rewrite little_bastard golang Docker image which has a issue with memory leak causing eventually docker container to restart after several hours of activity, but can handle more requests per second. If you need something that does more requests per second (e.g.: testing your app against DDOS attack) then Little Bastard image is better for you.

pobble/request_repeater aims to provide stable flow of repeating requests without crushing over time.

License

The gem is available as open source under the terms of the MIT License.