Massive overhaul to allow for multinode scenarios, and predictable return types.

src/migresia.erl

@@ -24,41 +24,46 @@
 
 -module(migresia).
 
--export([create_new_migration/1, create_new_migration/2, check/0, check/1, migrate/0, migrate/1, list_nodes/0]).
+-export([create_new_migration/2, check/1, migrate/1, list_disc_copy_nodes/0]).
 
--spec create_new_migration(string()) -> any().
-create_new_migration(Description) ->
-    create_new_migration(undefined, Description).
+-define(TABLE, schema_migrations).
 
 -spec create_new_migration(atom(), string()) -> any().
 create_new_migration(App, Description) ->
     {{Year, Month, Day}, {Hour, Minute, Second}} = calendar:local_time(),
     Filename = lists:flatten(io_lib:format("~w~2.2.0w~2.2.0w~2.2.0w~2.2.0w~2.2.0w_", [Year, Month, Day, Hour, Minute, Second]) ++ Description),
-    FullPathAndExtension = filename:join(migresia_migrations:get_priv_dir(App), Filename ++ ".erl"),
+    Path = migresia_migrations:get_priv_dir(App),
+    FullPathAndExtension = filename:join(Path, Filename ++ ".erl"),
     io:format("Creating new migration: ~p~n", [FullPathAndExtension]),
-    file:write_file(FullPathAndExtension, io_lib:fwrite("-module(~p).~n-behavior(db_migration).~n-export([up/0, down/0]). ~n~nup() -> ok.~n~ndown() -> throw(<<\"Downgraders not implemented.\">>).", [list_to_atom(Filename)])),
+    ok = filelib:ensure_dir(<<Path/binary, <<"/">>/binary>>),
+    ok = file:write_file(FullPathAndExtension, io_lib:fwrite("-module(~p).~n-behavior(db_migration).~n-export([up/0, down/0]). ~n~nup() -> ok.~n~ndown() -> throw(<<\"Downgraders not implemented.\">>).", [list_to_atom(Filename)])),
     io:format("Migration written.~n~n").
 
--spec check(atom()) -> any().
+-spec check(atom()) -> ok | {error, any()}.
 check(App) ->
-    Loaded = migresia_migrations:list_unapplied_ups(App),
-    if Loaded == [] ->
-            io:format("No migrations to apply.~n", []);
-       true ->
-            io:format("Migrations to apply: ~p~n", [ [X||{X,_} <- Loaded] ])
+    case start_mnesia(false) of
+        ok -> 
+            Loaded = migresia_migrations:list_unapplied_ups(App),
+            if Loaded == [] ->
+                    [];
+               true ->
+                    [ [X||{X,_} <- Loaded] ]
+            end;
+        {error, Error} -> {error, Error}
     end.
 
--spec check() -> any().
-check() -> check(undefined).
-
--spec migrate(atom()) -> any().
+-spec migrate(atom()) -> ok | {error, any()}.
 migrate(App) ->
-    Loaded = migresia_migrations:list_unapplied_ups(App),
-    lists:foreach(fun execute_up/1, Loaded).
-
--spec migrate() -> any().
-migrate() ->
-    migrate(undefined).
+    case start_mnesia(true) of
+        ok ->
+            case migresia_migrations:ensure_schema_table_exists() of
+                ok ->
+                    Loaded = migresia_migrations:list_unapplied_ups(App),
+                    lists:foreach(fun execute_up/1, Loaded);
+                {error, Error} -> Error
+            end;
+        {error, Error} -> {error, Error}
+    end.
 
 execute_up({Module, Short}) ->
     io:format("Executing up in ~s...~n", [Module]),
@@ -66,6 +71,27 @@ execute_up({Module, Short}) ->
     mnesia:dirty_write(schema_migrations, {schema_migrations, Short, true}),
     io:format(" => done~n", []).
 
-list_nodes() ->
-    mnesia:table_info(schema, disc_copies).
 
+
+-spec start_mnesia(boolean()) -> ok | {error, any()}.
+start_mnesia(RemoteToo) ->
+    io:format("Starting Mnesia...~n", []),
+    case application:ensure_started(mnesia) of
+        Other when Other /= ok -> io:format(" => Error:~p~n", [Other]), Other;
+        ok -> 
+            case RemoteToo of
+                false -> ok;
+                true -> {ResultList, BadNodes} = rpc:multicall(list_all_nodes(), application, ensure_started, [mnesia]),
+                    BadStatuses = [X || X <- ResultList, X /= ok],
+                    if BadNodes /= [] -> io:format(" => Error:~p~n", [not_all_nodes_running]), {error, not_all_nodes_running};
+                        BadStatuses /= [] -> io:format(" => Error:~p~n", [BadStatuses]), {error, BadStatuses};
+                        true -> io:format(" => started~n", []), ok
+                    end
+            end
+    end.
+
+list_all_nodes() ->
+    mnesia:table_info(schema, all_nodes).
+
+list_disc_copy_nodes() -> 
+    mnesia:table_info(schema, disc_copies).