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Hemera v1.2.0 Release Notes

  • Summary

    🔌 hemera 1.2.0 is focused on error handling, plugin dependencies

    • ⬆️ Upgrade time: low - none to a couple of hours for most users
    • Complexity: low - requires following the list of changes to verifying their impact
    • Risk: medium - type checks on error will fail because the hemera error was stripped
    • Dependencies: low - existing plugins will work as-is

    💥 Breaking Changes

    🔌 You get the exact error you have sent. Errors are wrapped only for framework errors (Parsing errors, Plugin registration errors, Timeout errors) or logging.

    🆕 New Features

    • 🔧 Enable Server policy to abort requests when the server is not able to respond cause (max memory, busy event-loop). Example Configurable
    • 🔧 Long stack traces by default. Configurable
    • 🔧 Detect message loops (abort the request and return an error). Example Configurable
    • 🔊 Enrich errors logs with details (pattern, app-name, timestamp).
    • Track network hops in error to identify which clients was involved. Example

    Migration Checklist

    👀 1. Pull the wrapped error one level up. For any case except for: HemeraParseError, HemeraError "Error during plugin registration, TimeoutError"

    Old:

    hemera.add({
  topic: 'email',
  cmd: 'send'
}, (resp, cb) => {
  cb(new Error('Uups'))
})

hemera.act({
  topic: 'email',
  cmd: 'send',
  email: '[email protected]',
  msg: 'Hi!'
}, (err, resp) => {
  expect(err).to.be.exists()
  expect(err.name).to.be.equals('BusinessError')
  expect(err.message).to.be.equals('Business Error') 
  expect(err.cause.name).to.be.equals('Error')
  expect(err.cause.message).to.be.equals('Uups')
  hemera.close()
  done()
})

    🆕 New:

    hemera.add({
  topic: 'email',
  cmd: 'send'
}, (resp, cb) => {
  cb(new Error('Uups'))
})

hemera.act({
  topic: 'email',
  cmd: 'send',
  email: '[email protected]',
  msg: 'Hi!'
}, (err, resp) => {
  expect(err).to.be.exists()
  expect(err.name).to.be.equals('Error')
  expect(err.message).to.be.equals('Uups')
  hemera.close()
  done()
})

    🔊 2. All logs are wrapped with the correct Hemera error subclass BusinessError, FatalError ...

    🔌 3. Plugin dependencies are declared with peerDependencies instead with dependencies property in the plugin.

    Old:

    exports.attributes = {
  dependencies: ['hemera-joi']
  pkg: require('./package.json')
}

    🆕 New:

    "peerDependencies": {
  "hemera-joi": "^1.0.4",
  "nats-hemera": "1.x || 2.x"
}