Using loads in a different language¶

Loads is built in a way that makes it possible to have runners written in different languages. It’s perfectly possible to have a runner in javascript or ruby, sending data to loads.

This is made possible by the use of zeromq to send inter-process (or even inter-machines!) messages.

This means you can write your load tests with whatever language you want, as long as the test-runner sends back its results in the zmq pipeline, respecting the format described in this document.

Implementations in other languages¶

Integration of loads with javascript, named loads.js

Loads messaging format¶

The messages sent to loads always contain a data_type key, which describes the type of that that’s being sent.

The messages respect the following rules:

All the data is JSON encoded.
Dates are expressed in ISO 8601 format, (YYYY-MM-DDTHH:MM:SS)
You should send along the worker id with every message. Each worker id should be different from each other.

A message generally looks like this:

{
    data_type: 'something',
    worker_id: '1',
    other_key_1: 'foo'
    other_key_2: 'bar'
}

loads_status¶

Some messages take a loads_status argument. loads_status is a list of values concerning the current status of the load. It contains, in this order:

cycles: the number of cycles that will be running in total
user: the number of users per cycle)
current_cycle: the cycle we are currently in
current_user: the current user that’s doing the requests

errors / exceptions¶

When errors / exceptions are caught, they are serialised and sent trough the wire, as well. When you see an exc *, it is a list containing this:

A string representation of the exception
A string representation of the exception class
The traceback / Stack trace.

Data types¶

Before and after you run the tests, you need to tell that you’re doing so:

startTestRun()
stopTestRun()

Tests¶

When using loads, you usually run a test suite. Tests start, stop, succeed and fail. Here are the APIs you can use:

addFailure(test_name, exc *, loads_status)
addError(test_name, exc *, loads_status)
addSuccess(test_name, loads_status)
startTest(test_name, loads_status)
stopTest(test_name, loads_status)

Requests¶

To track requests, you only have one method, named “add_hit” with the following parameters:

url, the URL of the request, for instance http://notmyidea.org
method, the HTTP method (GET, POST, PUT, etc.)
status, the response of the call (200)
started, the time when it started
elapsed, the number of seconds (decimal) the request took to run
loads_status, as already described

Sockets¶

If you’re also able to track what’s going on with the socket connections, then you can use the following messages:

socket_open()
socket_close()
socket_message(size) # the size, in bytes, that were transmitted via the websocket.

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