Connect the current node to a Chaperon cluster without taking on any work (not running any load test Session tasks).

Useful if you want to connect to a running cluster for inspecting running load tests and kicking off new ones without performing any load testing work on the connecting node.

Runs a given load_test module's scenarios concurrently, outputting metrics at the end.

• lt_mod LoadTest module to be executed

• options List of options to be used. Valid values are:

  • :print_results If set to true, will print all action results.
  • :export Can be set to any module implementing the Chaperon.Exporter behaviour. Defaults to Chaperon.Export.CSV. When using Chaperon.Export.S3 it defaults to the CSV export format. You can use another export format by wrapping it in a tuple, like so: {Chaperon.Export.S3, Chaperon.Export.JSON}
  • :output Can be set to a file path
  • :tag Can be set to be used when using the default export filename. Allows adding a custom 'tag' string as a prefix to the generated result output filename.

  • :metrics Filtering options for metrics Valid filters:

    - (metric) -> boolean
    - [metric_type]

Example

alias Chaperon.Export.JSON

# Prints results & outputs metrics in CSV (default) format at the end
Chaperon.run_load_test MyLoadTest, print_results: true

# Doesn't print results & outputs metrics in JSON format at the end
Chaperon.run_load_test MyLoadTest, export: JSON

# Outputs metrics in CSV format to metrics.csv file
Chaperon.run_load_test MyLoadTest, output: "metrics.csv"

# Outputs metrics in JSON format to metrics.json file
Chaperon.run_load_test MyLoadTest, export: JSON, output: "metrics.json"

# Outputs metrics in CCSV format to "results/<date>/MyLoadTest/master-<timestamp>.csv"
Chaperon.run_load_test MyLoadTest, tag: "master"

# Outputs metrics in JSON format to "results/<date>/MyLoadTest/master-<timestamp>.json"
Chaperon.run_load_test MyLoadTest, export: JSON, tag: "master"

# Tracks only calls in MyScenario (can take any function that returns `true` or `false`)
Chaperon.run_load_test MyLoadTest, tag: "master", metrics: fn
  {:call, {MyScenario, _}} ->
    true
  _ ->
    false
end

# You can also just pass a list of metric types/names:
Chaperon.run_load_test MyLoadTest metrics: [
  :run_scenario,
  :call,
  :post,
  :my_custom_metric
]

Called when an application is started.

This function is called when an application is started using Application.start/2 (and functions on top of that, such as Application.ensure_started/2). This function should start the top-level process of the application (which should be the top supervisor of the application's supervision tree if the application follows the OTP design principles around supervision).

start_type defines how the application is started:

• :normal - used if the startup is a normal startup or if the application is distributed and is started on the current node because of a failover from another node and the application specification key :start_phases is :undefined.
• {:takeover, node} - used if the application is distributed and is started on the current node because of a failover on the node node.
• {:failover, node} - used if the application is distributed and is started on the current node because of a failover on node node, and the application specification key :start_phases is not :undefined.

start_args are the arguments passed to the application in the :mod specification key (e.g., mod: {MyApp, [:my_args]}).

This function should either return {:ok, pid} or {:ok, pid, state} if startup is successful. pid should be the PID of the top supervisor. state can be an arbitrary term, and if omitted will default to []; if the application is later stopped, state is passed to the stop/1 callback (see the documentation for the c:stop/1 callback for more information).

use Application provides no default implementation for the start/2 callback.

Callback implementation for Application.start/2.