Revenant - What if GenServer flushed its state into PostgreSQL?
I've been using and actively fascinated by Oban over the last 4 years, and recently I wondered, why can't we make GenServers behave similarly to Oban jobs and:
- Recover their state after a crash or termination
- Terminate themselves when not used
- Store a trace of their execution
- And do all that without any additional dependencies, using the database we're already used to
I can think of a ton of cases where this might be useful in... Durable GenServers? LiveViews? Distributed GenServers that share state? Hot/Cold executions? Slow/Fast pools?
So I created a PoC library that does just that:
https://github.com/dimamik/revenant
defmodule Account do
use Revenant, repo: MyApp.Repo
def initial_state(_id), do: %{balance: 0}
def handle_call({:deposit, amount}, _from, state) do
{:reply, :ok, %{state | balance: state.balance + amount}}
end
def handle_call(:balance, _from, state) do
{:reply, state.balance, state}
end
end
Revenant.call({Account, "acct_42"}, {:deposit, 100})
#=> :ok - the new state is committed to Postgres before you see this
Please let me know what you think of the concept!
u/Unusual_Shame_3839 — 7 hours ago