Goload

Goload is a blackbox-exporter, which is a monitoring tool exposing metrics with status and latency from its targets. It's written to do a series of requests against a set of targets with the ability to pass data between requests. It'll then export it's metrics for Prometheus to scrape.

The easiest way to run it, is by using docker. You'll then configure it by a set of environment variables and a file with your target definitions.

Use cases

• Blackbox-exporter by tracking responses and latency from a set of targets
• Load testing by running this on many instances with a large number of concurrency
• Integration testing by testing your API with a set of pre-defined requests
• Synthetic traffic generator during development or in production to generate a baseline of metrics

How to run it

Goload comes shipped with Alpine as a docker image at spurge/goload

As a binary

go get github.com/spurge/goload
go install github.com/spurge/goload
goload -host localhost -port 9115 -stderrthreshold ERROR -concurrency 1 -sleep 1 -repeat -1 -target your-targets.yml

With docker

docker run -d -v $PWD/targets.yml:/targets.yml -e TARGETS=/targets.yml -p 9115:9115 spurge/goload
curl localhost:9115/metrics

Rolling your own docker image

FROM spurge/goload

COPY targets.yml /app

ENV TARGETS /app/targets.yml

and then ...

docker build -t goload-some-target .
docker run -d goload-some-target
curl localhost:9115/metrics

Environment varables

• HOST the host to listen on, default is 0.0.0.0
• PORT the port to listen on, default is 9115 (the same as Prometheus blackbox-exporter)
• LOG_LEVEL sets the verbosity by INFO, WARNING and ERROR, default is ERROR
• CONCURRENCY the number of concurrent workers, doing requests against your targets, default is 1
• SLEEP the time to sleep in seconds before running through your targets again, default is 1
• REPEAT the number of repeating target cycles, default is -1 which means infinite
• TARGETS the path to your targets defined in an yaml-file

Targets yaml-file

- name: login
  url: http://some-host/login
  params:
    some-query: parameter
  method: POST
  body: >
    {
      "username": "yumba",
      "password": "secret"
    }
  expect:
    status_code_re: '2[0-9]{2}'
    headers_re:
      Content-Type: 'application/json'
    body_re: '\{"user":\{"id":"[a-z0-9\-]+","name":"[a-z]+".*'
- name: profile
  url: 'http://some-host/profile/{{ fromJson "login" "user.id" }}'
  method: GET
  headers:
    Authentication: 'Bearer {{ fromJson "login" "user.auth.token" }}'

Passing data between targets

As for now, there's only support for parsing and passing json-data. The targets yaml file is treated as a go-lang template, which means that you can access some functionality within double curly-brackets {{ }}.

The json-data is fetched with the template function fromJson. It takes two arguments, the first is the name of the request/target and the second is the path to you data from the response body. The path is defined and parsed using the gjson-library.

See example above and the gjson documentation: https://github.com/tidwall/gjson