mnesia_cluster

mnesia_cluster is a simple application easy cluster mnesia and auto create mnesia table.

1. auto create mnesia table
2. auto merge mnesia table
3. cluster mnesia

Build

$ rebar3 compile

Start/Stop

1. start

make sure start mnesia_cluster before use mnesia, recommend start it after node up.

mnesia_cluster:start().

2. stop

mnesia_cluster:stop()

---

Config Cluster

mnesia_cluster will load configed nodes and dynamic join cluster

set env before start

%% set other nodes (will find and connect other nodes)
application:set_env(mnesia_cluster, mnesia_nodes, ['node1','node2'...]).

you can also config in .config file

[
  {mnesia_cluster,	[
		{mnesia_nodes, ['other@localhost','other2@localhost']}
	]}
].

---

Join Cluster

    %% try to join '[email protected]' cluster
    %% note: this will clean current node's data and copy data from '[email protected]'
    mnesia_cluster:join('[email protected]')

---

Leave cluster

    %% if leave successful, will delete current node's data
    mnesia_cluster:leave()

---

Define table

mnesia_cluster use module attribute 'mnesia_table' define table

define table with tuple

-mnesia_table({
 TableName,   %% the name of table
 TableOptions %% the options of table (see mnesia:create_table)
}).
%% ------------------------------------------------------------
%% example:
%% ------------------------------------------------------------
-module(chat).
%% define message table
%% notice: left table copy type (ram_copies, disc_copies, disc_only_copies) with blank
%%         it will auto insert node() in the list when do mnesia:create_table
-mnesia_table({message, [{type, bag}, {disc_copies, []}, {attributes, [id, uid, content]}]}).

define table by function

-mnesia_table(
 func   %% function name (make sure export func/0
).
@spec fun() -> [table_def()],
       table_def() :: {atom(), list()}
func() ->
 [].
%% ------------------------------------------------------------
%% example:
%% ------------------------------------------------------------
-module(chat).
-export([get_table/0]).
%% define message table
-mnesia_table(get_table).
get_table() ->
 [
   {message, [{type, bag}, {disc_copies, [node()]}, {attributes, recordinfo(message)}]},
   {users, [{type, set}, {disc_only_copies, [node()]}, {attributes, record_info(fields, user)}]}
 ].

---

Dynamic add defined table from modules

    %% make sure module [test1,test2] has table define
    mnesia_cluster:update([test1,test2]).

---

add module to application

mnesia_cluster only discover modules in application file, so you need add module to application file

myapp.app

{application, 'myapp',
 [{description, "test app"},
  {vsn, "0.1.0"},
  ....
  {modules, [chat]},
 ]}.