Erleans Postgres Persistence Provider

Erleans Persistence Provider backed by Postgres with library pgo.

Usage

Configure your Grains to use the Postgres provider and the database to use for the pgo pool that backs the provider in sys.config:

[{erleans, [{providers, #{pgo => #{module => erleans_provider_pgo,
                                   args => #{pool_size => 10,
                                             host => "127.0.0.1",
                                             database => "test",
                                             user => "test",
                                             password=> "test"}
                                  }}},

            {default_provider, pgo}]},

Now you can run a grain and save it to Postgres:

> Grain1 = erleans:get_grain(test_grain, <<"grain1">>).
> test_grain:activated_counter(Grain1).
> test_grain:save(Grain1).

test=# \dt
            List of relations
 Schema |      Name      | Type  | Owner
--------+----------------+-------+-------
 public | erleans_grains | table | test
 test=# select * from erleans_grains;
          grain_id          | grain_type | grain_ref_hash | grain_etag |
                                                      grain_state
                                                |        change_time
----------------------------+------------+----------------+------------+--------
--------------------------------------------------------------------------------
------------------------------------------------+----------------------------
 \x836d00000006677261696e31 | test_grain |       99587447 |   64845372 | \x83740
000000377116163746976617465645f636f756e7465726101771364656163746976617465645f636
f756e7465726101770c63616c6c5f636f756e7465726102 | 2024-11-10 10:25:31.303615
(1 row)

Run Tests

The project comes with a docker-compose.yaml file for starting Postgres:

$ docker compose up

After running this the tests will pass:

$ rebar3 ct

Note that unless you run docker compose down, as opposed to simply ctrl-c'ing out of the docker compose up when you run up again it will reuse the previous container and thus its database. To run a test from a blank state of the database be sure to run docker compose down after running tests or run with -V (docker compose up -V) which tells docker to recreate volumes.