Stampede.Scenario behaviour (stampede v0.2.0)

The behaviour of a load test.

Only run/1 is required:

defmodule MyApp.Load.Home do
  use Stampede.Scenario

  @impl true
  def options, do: [vus: 10, duration: [minute: 1]]

  @impl true
  def run(_vu) do
    {:ok, socket} = Stampede.Channels.connect("ws://localhost:4000/socket")
    {:ok, _reply} = Stampede.Channels.join(socket, "home")
    Process.sleep(500)
  end
end

use Stampede.Scenario declares the behaviour and nothing else.

Summary

Callbacks

options()

Returns the default options of the scenario. See Stampede.run/2.

run(vu)

Runs one iteration of a VU.

setup opts

Runs once before the first VU starts, in the process that called Stampede.run/2.

Callbacks

options()

(optional)

@callback options() :: keyword()

Returns the default options of the scenario. See Stampede.run/2.

run(vu)

@callback run(vu :: Stampede.VU.t()) :: term()

Runs one iteration of a VU.

Stampede calls it again as soon as it returns, until the VU is stopped. Sockets opened with Stampede.Channels.connect/2 during an iteration are closed when it returns, so a VU that should stay connected for the whole test must keep run/1 from returning, for example with a loop.

If run/1 raises, throws or exits, the error is counted under "iteration.errors" and the VU waits 100ms before its next iteration, so a failing scenario does not spin.

setup opts

(optional)

@callback setup(opts :: keyword()) :: term()

Runs once before the first VU starts, in the process that called Stampede.run/2.

It receives the options of the run, and what it returns is given to every VU as vu.data. Use it for work that should not be repeated, such as creating accounts or signing tokens.