Skip to content
/ poolboy Public
forked from basho/poolboy

A hunky Erlang worker pool factory

License

Apache-2.0, Unlicense licenses found

Licenses found

Apache-2.0
LICENSE
Unlicense
UNLICENSE
Notifications You must be signed in to change notification settings

Kyorai/poolboy

 
 

Poolboy - A hunky Erlang worker pool factory

Build Status

Usage

1> Worker = poolboy:checkout(PoolName).
<0.9001.0>
2> gen_server:call(Worker, Request).
ok
3> poolboy:checkin(PoolName, Worker).
ok

Example

This is an example application showcasing database connection pools using Poolboy and Will Glozer's epgsql.

example.app

{application, example, [
    {description, "An example application"},
    {vsn, "0.1"},
    {applications, [kernel, stdlib, sasl, crypto, ssl]},
    {modules, [example, example_worker]},
    {registered, [example]},
    {mod, {example, []}},
    {env, [
        {pools, [
            {pool1, [
                {size, 10},
                {max_overflow, 20}
			], [
                {hostname, "127.0.0.1"},
                {database, "db1"},
                {username, "db1"},
                {password, "abc123"}
            ]},
            {pool2, [
                {size, 5},
                {max_overflow, 10}
			], [
                {hostname, "127.0.0.1"},
                {database, "db2"},
                {username, "db2"},
                {password, "abc123"}
            ]}
        ]}
    ]}
]}.

example.erl

-module(example).
-behaviour(application).
-behaviour(supervisor).

-export([start/0, stop/0, squery/2, equery/3]).
-export([start/2, stop/1]).
-export([init/1]).

start() ->
    application:start(?MODULE).

stop() ->
    application:stop(?MODULE).

start(_Type, _Args) ->
    supervisor:start_link({local, example_sup}, ?MODULE, []).

stop(_State) ->
    ok.

init([]) ->
    {ok, Pools} = application:get_env(example, pools),
    PoolSpecs = lists:map(fun({Name, SizeArgs, WorkerArgs}) ->
        PoolArgs = [{name, {local, Name}},
            		{worker_module, example_worker}] ++ SizeArgs,
        poolboy:child_spec(Name, PoolArgs, WorkerArgs)
    end, Pools),
    {ok, {{one_for_one, 10, 10}, PoolSpecs}}.

squery(PoolName, Sql) ->
    poolboy:transaction(PoolName, fun(Worker) ->
        gen_server:call(Worker, {squery, Sql})
    end).

equery(PoolName, Stmt, Params) ->
    poolboy:transaction(PoolName, fun(Worker) ->
        gen_server:call(Worker, {equery, Stmt, Params})
    end).

example_worker.erl

-module(example_worker).
-behaviour(gen_server).
-behaviour(poolboy_worker).

-export([start_link/1]).
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
         code_change/3]).

-record(state, {conn}).

start_link(Args) ->
    gen_server:start_link(?MODULE, Args, []).

init(Args) ->
    Hostname = proplists:get_value(hostname, Args),
    Database = proplists:get_value(database, Args),
    Username = proplists:get_value(username, Args),
    Password = proplists:get_value(password, Args),
    {ok, Conn} = pgsql:connect(Hostname, Username, Password, [
        {database, Database}
    ]),
    {ok, #state{conn=Conn}}.

handle_call({squery, Sql}, _From, #state{conn=Conn}=State) ->
    {reply, pgsql:squery(Conn, Sql), State};
handle_call({equery, Stmt, Params}, _From, #state{conn=Conn}=State) ->
    {reply, pgsql:equery(Conn, Stmt, Params), State};
handle_call(_Request, _From, State) ->
    {reply, ok, State}.

handle_cast(_Msg, State) ->
    {noreply, State}.

handle_info(_Info, State) ->
    {noreply, State}.

terminate(_Reason, #state{conn=Conn}) ->
    ok = pgsql:close(Conn),
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

Options

  • name: the pool name
  • worker_module: the module that represents the workers
  • size: maximum pool size
  • max_overflow: maximum number of workers created if pool is empty

Authors

License

Poolboy is available in the public domain (see UNLICENSE). Poolboy is also optionally available under the Apache License (see LICENSE), meant especially for jurisdictions that do not recognize public domain works.

About

A hunky Erlang worker pool factory

Resources

License

Apache-2.0, Unlicense licenses found

Licenses found

Apache-2.0
LICENSE
Unlicense
UNLICENSE

Stars

Watchers

Forks

Packages

No packages published

Languages

  • Erlang 99.0%
  • Makefile 1.0%