Orleansalpha

Run Motoko actors as Orleans grains, with state in Postgres and Orleans reminders as timers.

Each actor key is an Orleans grain in the silo. Orleans places it and delivers its messages one at a time; its state is stored in Postgres, and timers are Orleans reminders.

You also need the moxzi SDK and hosts bundles; see Actor platforms.

Prerequisites#

.NET 8 SDK
Docker, for Postgres

Create and run a project#

moxzi host new orleans hello
cd hello
ONCE=1 ./run.sh

Among the build and platform log lines, the demo prints Counter/1.inc() -> [1]. Run it again and it prints [2]: the host is a new process, and the actor's state comes back from the platform's store.

ONCE=1 exits after the demo. Without it, the host keeps running on port 8090 (set PORT to change it), and you can call any key:

curl -X POST localhost:8090/actors/Counter/2/method/inc \
  -H 'content-type: application/json' -d '[]'

--example ledger and --example saga work on Orleans too; see Examples.

The project#

Path	Contents
`actor.mo`	The `Counter` actor type. Each key `Counter/ID` is a separate actor
`host/`	moxzi's Orleans adapter. It's yours to change
`run.sh`	Builds the actor and the host, starts what Orleans needs, and runs the demo

Change actor.mo and run ./run.sh again. New keys use the new code. Existing keys keep their code until they're upgraded; host/README.md describes upgrades.

How it maps#

	Handled by
One message at a time per key	The Orleans grain
Placement	The Orleans cluster
Actor state	Postgres, in a Docker container named `moxzi-hello-pg` on port 55432 that `run.sh` starts and leaves running. Set `DATABASE_URL` to use your own database, or `PG_PORT` to use another port
Durable timers	Orleans reminders

Remove the database container with docker rm -f moxzi-hello-pg when you're done.

Configuration#

Variable	Default	Effect
`PORT`	`8090`	The host's HTTP port
`MOXZI_HOST_TOKEN`	random	Token for the host's control endpoints (`/_moxzi/*`)
`DATABASE_URL`	a local container	Postgres connection string
`PG_PORT`	`55432`	Port for the local Postgres container. All projects use the same default, so only one can run at a time