/pgapp

Erlang Postgres application that uses Poolboy and deals with the database being unavailable

Primary LanguageErlangMIT LicenseMIT

pgapp

This code is a front end for epgsql that adds a pool (poolboy, for the moment), and code to isolate crashes in the epgsql library: if your database goes down, you probably don't want the rest of the application to fail as well.

Build and start the application with Make:

- Copy and/or rename the file `pgapp.config.sample` into `pgapp.config`
- Enter your configuration data in `pgapp.config`
- Run:

    ~:$ make
    ~:$ make run

- To test it, just run:

    > pgapp:equery(a_pool_name, "select current_date", []).

  where `a_pool_name` is the name of one of the pools in your `pgapp.config` file.

API use: - Simple pool:

    application:ensure_all_started(pgapp).
    pgapp:connect([{size, 10}, {database, "mydb"}, {username, "foo"}, {password, "bar"}]).
    pgapp:equery("select current_date", []),
    pgapp:with_transaction(fun(Conn) ->
                                 pgapp:squery(Conn, "update ..."),
                                 pgapp:squery(Conn, "delete from ..."),
                                 pgapp:equery(Conn, "select ? from ?", ["*", Table])
                           end).

- Multi pool:

    application:ensure_all_started(pgapp).
    pgapp:connect(a_pool_name, [{size, 10}, {database, "mydb"}, {username, "foo"}, {password, "bar"}]).
    pgapp:equery(a_pool_name, "select current_date", []).

The equery and squery API's are the same as those of epgsql: https://github.com/epgsql/epgsql

Note: It is still experimental, and is likely to break. The API is not stable!

See [Changelog].