Persistence
Persistence allows @node-ts/bus-workflow to maintain durable state in an underlying provider, and therefore run as a stateless service. This is important for a number of reasons:
- The workflow service can be treated as an ephemeral service that can be scaled in and out at will
- Execution of each workflow can be handled by a pool of distributed workflow services
- Workflow state will persist regardless of how many services are running, if any
By default, @node-ts/bus-workflow uses an in-memory persistence provider. This is fine to use when playing with the package and doing casual development, however it's not intended for production use as the state won't survive a process restart.
The following persistence providers are currently available:
Implementing a Persistence
Implementing a new transport is relatively simple (and encouraged!). This can be done by implementing the Persistence<> interface from @node-ts/bus-workflow. If you'd like to contribute your persistence adapter back to @node-ts/bus then please fork this repo, add a new package at /packages/bus-<persistence-name> and create a PR back to this repository.
Persistence adapters should be created and then registered in a new inversify module so that they consumers can use the persistence just by loading the module.
For an example of a persistence implementation, see the code for the @node-ts/bus-postgres persistence adapter.