From 2201744eda7da53d652035c588dddd6bf9b06c76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Henrique=20Ferreira=20de=20Freitas?=
 <joao.freitas@ekinops.com>
Date: Tue, 9 Apr 2024 16:28:44 -0300
Subject: [PATCH] Add application config option to configure mnesia copies

The config parameter can be: disc_copies or ram_copies. And the
default is disc_copies.
---
 src/canister.app.src | 4 +++-
 src/canister.erl     | 6 +++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/canister.app.src b/src/canister.app.src
index 4004798..2a80e78 100644
--- a/src/canister.app.src
+++ b/src/canister.app.src
@@ -11,7 +11,9 @@
   {included_applications, [
     mnesia
   ]},
-  {env,[]},
+  {env,[
+    {mnesia_table_copies, disc}
+  ]},
   {modules, []},
 
   {licenses, ["MIT"]},
diff --git a/src/canister.erl b/src/canister.erl
index dd80b56..eaf25fe 100644
--- a/src/canister.erl
+++ b/src/canister.erl
@@ -45,8 +45,12 @@ init_tables() ->
     init_table(canister_times, record_info(fields, canister_times)).
 
 init_table(Table, Fields) ->
+    MnesiaCopies = case application:get_env(canister, mnesia_table_copies, disc) of
+        disc -> disc_copies;
+        ram -> ram_copies
+    end,
     Res = mnesia:create_table(Table, [
-        {disc_copies, [node()]},
+        {MnesiaCopies, [node()]},
         {attributes, Fields}
     ]),
     canister_log:info("Initializing Table: ~p: ~p",[Table, Res]),