Event-sourced autonomous service toolkit for Node.js
yarn add @articulate/hermes
Follow the setup instructions for Message DB to initialize the message store, or use this Docker image for local dev. Then provide connection options as below:
// server/lib/hermes.js
module.exports = require('@articulate/hermes')({
connectionString: process.env.MESSAGE_STORE_URI
})You'll need at least a connectionString, but see the following for the full list of available options:
Note: You may alternatively specify the connection options using standard Postgres environment variables.
See the full documentation here: https://articulate.github.io/hermes/
You can also host the docs locally by cloning the repo and running:
npm i docsify-cli -g
yarn docs
Local docs will then be available at: http://localhost:4000
Hermes uses the debug library to output raw logs. To turn on all of the logs, include the following environment variable:
DEBUG=hermes:*
When debugging locally, these additional variables may also help. See the debug docs for the full list of options.
DEBUG_COLORS=true
DEBUG_DEPTH=null
DEBUG_HIDE_DATE=true
To help you test your autonomous services, Hermes ships with an in-memory substitute that passes the same test suite as the default Message DB implementation. Enable it with the { mock: true } flag. When enabled, Hermes will ignore any connection options specified, and will not connect to Postgres.
In addition, you may clear the in-memory store after each test using hermes.store.clear().
const hermes = require('@articulate/hermes')({
mock: process.env.NODE_ENV === 'test'
})
afterEach(() => {
hermes.store.clear()
})Read more about testing with Hermes in the section on entity caching.
Not for production use. The in-memory substitute implementation is only intended for testing.
The Hermes tests run in Travis CI, but you can run the tests locally with docker-compose like so:
docker-compose build
docker-compose run --rm test