Test Scripts

An Artillery test script is a YAML file (opens in a new tab) composed of two main sections: config and scenarios.

The scenarios section contains definitions of VU behavior.

The config section sets runtime configuration for the test such as the URI of the system being tested, load phase configuration, plugins, and protocol-specific settings such as HTTP response timeouts.

config section

The config section usually defines the target (the hostname or IP address of the system under test), the load progression, and protocol-specific settings, such as HTTP response timeouts or Socket.io transport options. It may also be used to load and configure plugins and custom JS code.

target - target service

config.target sets the endpoint of the system under test, such as a hostname, an IP address or a URI.

The format of this field depends on the system you're testing and the environment it runs in. For example, for an HTTP-based application, it's typically the protocol + hostname (e.g. http://myapp.staging.local). For a WebSocket server, it's usually the hostname (and optionally the port) of the server (e.g. ws://127.0.0.1), and so on.

phases - load phases

A load phase defines how Artillery generates new virtual users (VUs) in a specified time period. For example, a typical performance test will have a gentle warm-up phase, followed by a ramp-up phase, and finalizing with a maximum load for a duration of time.

config.phases is an array of phase definitions that Artillery goes through sequentially.

Load Phase types

Four kinds of phases are supported:

1. A phase with a duration and a constant arrival rate of a number of new VUs per second
2. A linear ramp-up phase where the number of new arrivals increases linearly over time
3. A phase that generates a fixed count of new arrivals over a period of time
4. A pause phase which generates no new VUs for a duration of time

Load Phase - additional options

• maxVusers: You can cap the total number of VUs in any phase with this option. Use this to restrict concurrency.
• name: You can give a name to a phase to make it easier to identify in CLI logs and Artillery Cloud dashboards.
• duration: You can specify the duration of a phase in seconds or in a human-readable format (see below).

Using time units for duration and pause

The default unit for duration and pause is seconds, and Artillery converts everything to seconds under the hood.

However, you can also provide any human-readable format from the ms package (opens in a new tab). Here's a few examples:

This is especially useful for longer durations (e.g. soak tests) where seconds might not be the best way to visualise time.

Load phase examples

Constant arrival rate

The following example generates 50 virtual users every second for 5 minutes:

config:
  target: 'https://staging.example.com'
  phases:
    - duration: 300
      arrivalRate: 50

The following example generates 10 virtual users every second for 5 minutes, with no more than 50 concurrent virtual users at any given time:

config:
  target: 'https://staging.example.com'
  phases:
    - duration: 300
      arrivalRate: 10
      maxVusers: 50

Ramp up rate

The following example ramps up the arrival rate of virtual users from 10 to 50 over 2 minutes:

config:
  target: 'https://staging.example.com'
  phases:
    - duration: 120
      arrivalRate: 10
      rampTo: 50

Fixed number of arrivals per second

The following example creates 20 virtual users in 60 seconds (one virtual user approximately every 3 seconds):

config:
  target: 'https://staging.example.com'
  phases:
    - duration: 60
      arrivalCount: 20

A do-nothing pause phase

The following example does not send any virtual users for 60 seconds:

config:
  target: 'https://staging.example.com'
  phases:
    - pause: 60

Using time unit conversion

The following is now a valid config describing two phases: a ramp up phase lasting 30 minutes, followed by a sustain phase of 3 hours.

phases:
  - duration: 30m
    arrivalRate: 1
    rampTo: 100
    name: ramp up
  - duration: 3h
    arrivalRate: 100
    name: sustain

How do ramps work?

Think of the rampTo setting as a shortcut for manually writing out a sequence of arrival phases. For example, let's say you have the following load phase defined:

phases:
  - duration: 100
    arrivalRate: 1
    rampTo: 50

The above load phase is equivalent to the following:

phases:
  - arrivalRate: 1
    duration: 2
  - arrivalRate: 2
    duration: 2
  - arrivalRate: 3
    duration: 2
  -
    #  ... etc ...
  - arrivalRate: 50
    duration: 2

Partial arrival rates are rounded up (ie: 1.5 arrivals -> 2 arrivals), this may happen in some scenarios.

environments - config profiles

Typically, you may want to reuse a load testing script across multiple environments with minor tweaks. For instance, you may want to run the same performance tests in development, staging, and production. However, for each environment, you need to set a different target and modify the load phases.

Instead of duplicating your test definition files for each environment, you can use the config.environments setting. It allows you to specify the number of named environments that you can define with environment-specific configuration.

A typical use-case is to define multiple targets with different load phase definitions for each of those systems:

config:
  target: 'http://service1.acme.corp:3003'
  phases:
    - duration: 10
      arrivalRate: 1
  environments:
    production:
      target: 'http://service1.prod.acme.corp:44321'
      phases:
        - duration: 1200
          arrivalRate: 10
    local:
      target: 'http://127.0.0.1:3003'
      phases:
        - duration: 1200
          arrivalRate: 20

When running your performance test, you can specify the environment on the command line using the -e flag. For example, to execute the example test script defined above with the staging configuration:

artillery run -e staging my-script.yml

The $environment variable

When running your tests in a specific environment, you can access the name of the current environment using the $environment variable.

For example, you can print the name of the current environment from a scenario during test execution:

config:
  environments:
    local:
      target: 'http://127.0.0.1:3003'
      phases:
        - duration: 120
          arrivalRate: 20
scenarios:
  - flow:
      - log: 'Current environment is set to: {{ $environment }}'

If you run the test with artillery run -e local my-script.yml, Artillery will print "Current environment is set to: local".

plugins - plugin config

This section can be used to configure Artillery plugins. Please see plugins overview for details.

processor - load custom code

Artillery can run custom code via "hooks" at various points in the test lifecycle. For example, you can use custom code to generate dynamic payloads, run custom checks, or track custom metrics.

Custom code is loaded through the config.processor attribute. The value of config.processor should be the path to one of:

• A CommonJS module with a .js extension
• An ESM module with a .mjs extension Added inv2.0.7
• A TypeScript module with a .ts extension. Supported for local and AWS Fargate runs only, and currently does not work with AWS Lambda. Added inv2.0.4

For example, to load a CommonJS module from ./my-functions.js:

config:
  target: 'https://my.app.dev'
  phases:
    - duration: 300
      arrivalRate: 1
  processor: './my-functions.js'
scenarios:
  -  # ... scenarios definitions here ...

Function signatures

Hook functions may be async (opens in a new tab) starting from Artillery v2.0.7. Async functions that throw an error stop the execution of the current VU.

Callback-based hooks will receive a next() callback that must be called with no arguments for the scenario to continue. Calling the next() callback with an error object will stop the execution of the current VU.

Preventing bundling of TypeScript packages

Artillery bundles your TypeScript code into a single CommonJS module. Sometimes you may run into issues with the bundling of some npm packages. If that happens, you can mark specific packages as external to prevent them from being bundled.

For example, to mark lodash and zod as external:

config:
  bundling:
    external: ['lodash', 'zod']

If you mark a package as external, you will need to ensure that it is available in the environment where you run your test. In the case of Fargate tests, make sure to include a package.json file next to the test script with the dependencies, so Fargate will install the dependencies in the workers. For example:

{
  "dependencies": {
    "lodash": "^4.17.21",
    "zod": "^3.0.0"
  }
}

payload - loading data from CSV files

You can use a CSV file to provide dynamic data to test scripts. For example, you might have a list of usernames and passwords that you want to use to test authentication in your API. Artillery allows you to load, parse and map data in CSV files to variables which can be used inside virtual user scenarios.

Artillery supports two ways of providing data from a CSV file to virtual users:

1. A row at a time, i.e. each VU gets data from just one row
2. All rows, i.e. each VU has access to all of the data

For example, you may have a file named users.csv with the following contents:

testuser1,password1
testuser2,password2
testuser3,password3

To access this information in a test definition, you can load the data from the CSV file using config.payload setting:

config:
  payload:
    # path is relative to the location of the test script
    path: 'users.csv'
    fields:
      - 'username'
      - 'password'
scenarios:
  - flow:
      - post:
          url: '/auth'
          json:
            username: '{{ username }}'
            password: '{{ password }}'

In this example, we tell Artillery to load users.csv file with the path setting and make the variables username and password available in scenarios containing values from one of the rows in the CSV file.

We can also make the entire dataset available to every VU, using loadAll, and loop through it in our scenario:

config:
  payload:
    path: 'users.csv'
    fields:
      - 'username'
      - 'password'
    loadAll: true
    name: auth # refer to the data as "auth"
scenarios:
  - flow:
      - loop:
          - post:
              url: '/auth'
              json:
                username: '{{ $loopElement.username }}'
                password: '{{ $loopElement.password }}'
        over: auth

It's also possible to import multiple CSV files in a test definition by setting payload as an array:

payload:
  - path: 'pets.csv'
    fields:
      - 'species'
      - 'name'
  - path: 'urls.csv'
    fields:
      - 'url'

You can also dynamically load different CSV files depending on the environment you set with the -e flag by using the $environment variable when specifying the path:

payload:
  - path: '{{ $environment }}-logins.csv'
    fields:
      - 'username'
      - 'password'

An example for dynamically loading a payload file is to load a different set of usernames and passwords to use with an authentication endpoint when running the same test in different environments.

Payload file options

• fields - Names of variables to use for each column in the CSV file
• order (default: random) - Control how rows are selected from the CSV file for each new virtual user.
  • This option may be set to sequence to iterate through the rows in a sequence (looping around and starting from the beginning after reaching the last row). Note that this will not work as expected when running distributed tests, as each node will have its own copy of the CSV data.
• skipHeader (default: false) - Set to true to make Artillery skip the first row in the file (typically the header row).
• delimiter (default: ,) - If the payload file uses a delimiter other than a comma, set this option to the delimiter character.
• cast (default: true) - By default, Artillery will convert fields to native types (e.g. numbers or booleans). To keep those fields as strings, set this option to false.
• skipEmptyLines (default: true) - By default, Artillery skips empty lines in the payload. Set to false to include empty lines.
• loadAll and name - set loadAll to true to provide all rows to each VU, and name to a variable name which will contain the data

Example

The following example loads a payload file called users.csv, skips the first row, and selects each subsequent row sequentially:

config:
    payload:
      path: "users.csv"
      fields:
        - "username"
        - "password"
      order: sequence
      skipHeader: true
  scenarios:
    - # ... the rest of the script

variables - inline variables

Variables can be defined in the config.variables section and used in scenario definitions.

Variables work similarly to loading fields from a payload file. You can define multiple values for a variable and access them randomly in your scenarios. For instance, the following example defined two variables, {{ id }} and {{ postcode }}, with multiple values:

config:
  target: 'http://app01.local.dev'
  phases:
    - duration: 300
      arrivalRate: 25
  variables:
    postcode:
      - 'SE1'
      - 'EC1'
      - 'E8'
      - 'WH9'
    id:
      - '8731'
      - '9965'
      - '2806'

tls - self-signed certificates

This setting may be used to tell Artillery to accept self-signed TLS certificates:

config:
  tls:
    rejectUnauthorized: false

ensure - SLO checks

Please see the guide for ensure plugin.

defaults - Default config

You can set default config for your scenario through this option, e.g. think options.

includeFiles - explicitly bundling files with the test

When running a test on AWS Lambda or AWS Fargate, Artillery will automatically detect any custom JS modules (including their npm dependencies) and CSV files used with the config.payload setting and bundle them into the test package that gets sent to the workers.

You may want to include other files that Artillery cannot automatically detect, such as a file that is read with fs.readFileSync in a custom function. You can use the config.includeFiles to include those files:

config:
  target: 'https://example.net'
  includeFiles:
    - foo.json
    - bar.xml

Using environment variables

Values can be set dynamically via environment variables which are available under $env template variable. This functionality helps set different configuration values without modifying the test definition and keeping secrets out of your source code.

For example, to set a default HTTP header for all requests via the SERVICE_API_KEY environment variable, your test definition would look like this:

config:
  target: https://service.acme.corp
  phases:
    - duration: 600
      arrivalRate: 10
scenarios:
  - flow:
      - get:
          url: '/'
          headers:
            x-api-key: '{{ $env.SERVICE_API_KEY }}'

You can keep the API key out of the source code and provide it on the fly when executing the test script:

export SERVICE_API_KEY="012345-my-api-key"
artillery run my-test.yaml

You can also set multiple environment variables from a file using the --env-file flag.

scenarios section

The scenarios section contains definitions for one or more scenarios for the virtual users (VUs) that Artillery will create. Each scenario is a series of steps representing a typical sequence of requests or messages sent by a user of an application.

A scenario definition is an object which requires a flow attribute and may contain additional optional attributes:

• flow (required) - An array of operations that a virtual user performs. For example, you can execute GET and POST requests for an HTTP-based application or emit events for a Socket.IO test.
• name (optional) - Assign a descriptive name to a scenario, which can be helpful in reporting.
• weight (optional) - Allows for the probability of a scenario being picked by a new virtual user to be "weighed" relative to other scenarios.

Each Artillery engine used during testing supports additional scenario attributes. Read the documentation to learn what you can do in a scenario for each Artillery engine:

• Testing HTTP
• Testing with Playwright
• Testing Socket.IO
• Testing WebSockets

before and after sections

The before and after are optional top level sections that can be used to run an arbitrary scenario once per test definition, before or after the scenarios section has run. Any variable captured during the before execution will be available to all virtual users and to the after scenario. These sections can be useful to set up or tear down test data.

The following example calls an authentication endpoint and captures an auth token before the virtual users arrive. After the scenarios have run, the after section invalidates the token:

config:
  target: 'http://app01.local.dev'
  phases:
    - duration: 300
      arrivalRate: 25
 
before:
  flow:
    - log: 'Get auth token'
    - post:
        url: '/auth'
        json:
          username: 'myUsername'
          password: 'myPassword'
        capture:
          - json: $.id_token
            as: token
scenarios:
  - flow:
      - get:
          url: '/data'
          headers:
            authorization: 'Bearer {{ token }}'
after:
  flow:
    - log: 'Invalidate token'
    - post:
        url: '/logout'
        json:
          token: '{{ token }}'

All engines supported

The before and after sections support usage of any engine (custom or built-in). You must make sure to specify the engine desired in both config and the before/after section. If the engine is not specified, the default engine (http) will be used.

For example, to use the playwright engine in the before section, you would specify the following:

config:
  ...
  engines:
    playwright: {}
  processor: ./processor.js
 
before:
  engine: playwright
  flowFunction: someActionFunction
 
scenarios:
  - engine: playwright
    flowFunction: yourFlowFunction

Scenario weights

Weights allow you to specify that some scenarios should be picked more often than others. If you have three scenarios with weights 1, 2, and 5, the scenario with the weight of 2 is twice as likely to be picked as the one with a weight of 1, and 2.5 times less likely than the one with a weight of 5. Or in terms of probabilities:

• scenario 1: 1/8 = 12.5% probability of being picked
• scenario 2: 2/8 = 25% probability of being picked
• scenario 3: 5/8 = 62.5% probability of being picked

Scenario weights are optional and set to 1 by default, meaning each scenario has the same probability of getting picked.

Example of weight usage

scenarios:
  # Approximately 60% of all VUs will run this scenario.
  - name: '/common route'
    weight: 6
    flow:
      - get:
          url: '/common'
 
  # Approximately 30% of all VUs will run this scenario.
  - name: '/average route'
    weight: 3
    flow:
      - get:
          url: '/average'
 
  # Approximately 10% of all VUs will run this scenario.
  - name: '/rare route'
    weight: 1
    flow:
      - get:
          url: '/rare'

Running a single weighted scenario

You can use the flag --scenario-name to run a specific scenario, allowing you to reuse weighted scenarios as individual scenarios. For example, to run the scenario named /rare route from the example above:

  artillery run --scenario-name "/rare route" my-test.yaml

Default variables

Artillery sets a number of template variables for each test run which are available in all test scripts.

Test-level variables

Test-level variables are available anywhere in the test script, i.e. in both the config and the scenarios sections.

• $env - environment variables including those set through the --env-file flag
• $testId - unique ID of the current test run Added inv2.0.6
• $environment - the value of the environment flag (-e or --environment)
• $dirname - the directory of the test config (config or scenario file) Added inv2.0.12
• target - the value of config.target (or the --target flag)

Scenario-level variables

Scenario-level variables are available only in the scenarios section of the test script.

• $uuid - unique ID of the virtual user