asl-validator

asl-validator

A simple Amazon States Language validator based on JSON schemas.

When writing your state machine (for AWS step functions), you can't locally validate you state machine definition without creating it. asl-validator makes it possible.

Install

# Use via the CLI
npm install -g asl-validator
# Use in your code
npm install asl-validator

CLI

$ asl-validator --help

  Usage: asl-validator [options]

  Amazon States Language validator


  Options:

    -v, --version                       output the version number
    --json-definition <jsonDefinition>  JSON definition
    --json-path <jsonPath>              JSON path
    --silent                            silent mode
    -h, --help                          output usage information

Return status:

• 0 if state machine definition is valid
• 1 if state machine definition is invalid
• 2 if an exception occurs

In your code

const aslValidator = require('asl-validator');
const definition = require('./path/to/my/state/machine/json/definition');
const { isValid, errors } = aslValidator(definition);
if (isValid) {
  console.log('✓ State machine definition is valid')
} else {
  console.errors('✕ State machine definition is invalid:', errors);
}

Test

npm run test

Lint

npm run lint

See also

• ASL specifications
• ASL documentation on AWS website
• Blog post from the creator of ASL explaining the pros and cons of a JSON schema based validator. An RFC based looks really interesting, but still the JSON schema approach seems more flexible and evolutive.