Revert "Remove table replica functions."

This reverts commit 529f15c301.

We want to be able to move things around in the end.

storage/src/storage.erl

@@ -46,9 +46,11 @@ file:
 -export([start_link/0]).
 
 % Public bucket operation functions
--export([add_node/1, create/1, create/2, create/3,
+-export([add_node/1, add_replica/2, add_replica/3,
-    grow/1, grow/2, grow/3, remove/1,
+    create/1, create/2, create/3,
-    remove/2, shrink/1, shrink/2]).
+    delete_replica/2, grow/1, grow/2, grow/3,
+    move/3, remove/1, remove/2, shrink/1,
+    shrink/2]).
 
 % Public record operation functions
 -export([delete/2, list/2, read/2, write/3, write/4]).
@@ -111,6 +113,59 @@ Bootstrap and add the node `b@piwa` to the storage cluster.
 add_node(Node) ->
 	gen_server:call(?MODULE, {node, Node}).
 
+-doc """
+Create a replica of the given `Bucket` on `Node`.
+
+Spec:
+
+```
+-spec add_replica(Bucket, Node, Type) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Node :: atom(),
+	Type :: disc_copies | disc_only_copies | ram_copies,
+	Reason :: term().
+```
+
+`Type` determines the kind of replica the destination node will manage,
+be it on disc, RAM, or both. The possible values for `Type` means:
+
+- ram_copies: the replica will be kept only in RAM on the destination node.
+- disc_copies: the replica will be in RAM and also on disc.
+- disc_only_copies: the replica will reside on disc only.
+
+Example:
+
+Add a disk-only replica of the bucket "objects", on the node "pri@lab":
+
+```
+add_replica(objects, 'pri@lab', disc_only_copies).
+ok
+```
+""".
+-spec add_replica(Bucket, Node, Type) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Node :: atom(),
+	Type :: disc_copies | disc_only_copies | ram_copies,
+	Reason :: term().
+
+add_replica(Bucket, Node, Type) ->
+	gen_server:call(?MODULE, {replica, Bucket, Node, Type}).
+
+-doc """
+Same as:
+
+```
+add_replica(Bucket, Node, disc_only_copies).
+```
+""".
+-spec add_replica(Bucket, Node) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Node :: atom(),
+	Reason :: term().
+
+add_replica(Bucket, Node) ->
+	gen_server:call(?MODULE, {replica, Bucket, Node, disc_only_copies}).
+
 -doc """
 Same as
 
@@ -184,6 +239,28 @@ add replicas of it calling the `add_replica/3` function.
 create(Bucket, Nodes, Type) ->
 	gen_server:call(?MODULE, {create, Bucket, Nodes, Type}).
 
+-doc """
+Delete a bucket replica.
+
+Spec:
+
+```
+-spec delete_replica(Bucket, Node) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Node :: atom(),
+	Reason :: term().
+```
+
+Delete the `Bucket` replica from the given `Node`.
+""".
+-spec delete_replica(Bucket, Node) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Node :: atom(),
+	Reason :: term().
+
+delete_replica(Bucket, Node) ->
+	gen_server:call(?MODULE, {delete_replica, Bucket, Node}).
+
 -doc """
 Same as:
 
@@ -231,6 +308,7 @@ added partition, will increase the bucket size by 2GB.
 That is, the total size increase of the bucket will be `Num` * 2GB.
 
 The created partitions are going to be replicated on the given list of `Nodes`,
+with priority given to nodes based on the order of the list.
 
 Example:
 
@@ -253,6 +331,31 @@ them on 'lab2@sec' with a total size increase of 4 * 2GB = 8GB.
 grow(Bucket, Nodes, Num) ->
 	gen_server:call(?MODULE, {grow, Bucket, Nodes, Num}).
 
+-doc """
+Move a bucket replica copy between nodes.
+
+Spec:
+
+```
+-spec move(Bucket, Source, Dest) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Source :: atom(),
+	Dest :: atom(),
+	Reason :: term().
+```
+
+The copy of `Bucket` living on `Source`, will be moved to `Dest` and deleted
+from the source node once the operation is completed.
+""".
+-spec move(Bucket, Source, Dest) -> ok | {error, Reason} when
+	Bucket :: atom(),
+	Source :: atom(),
+	Dest :: atom(),
+	Reason :: term().
+
+move(Bucket, Source, Dest) ->
+	gen_server:call(?MODULE, {move, Bucket, Source, Dest}).
+
 -doc """
 Delete the given `Bucket` and all it's replicas.
 
@@ -540,12 +643,24 @@ handle_call({create, Bucket, Nodes, Type}, _From, State) ->
 		{aborted, Reason} -> {reply, {error, Reason}, State}
 	end;
 
+handle_call({delete_replica, Bucket, Node}, _From, State) ->
+	case mnesia:del_table_copy(Bucket, Node) of
+		{atomic, _} -> {reply, ok, State};
+		{aborted, Reason} -> {reply, {error, Reason}, State}
+	end;
+
 handle_call({grow, Bucket, Nodes, Num}, _From, State) ->
 	case grow_bucket(Bucket, Nodes, Num) of
 		ok -> {reply, ok, State};
 		{error, Reason} -> {reply, {error, Reason}, State}
 	end;
 
+handle_call({move, Bucket, Source, Dest}, _From, State) ->
+	case mnesia:move_table_copy(Bucket, Source, Dest) of
+		{atomic, ok} -> {reply, ok, State};
+		{aborted, Reason} -> {reply, {error, Reason}, State}
+	end;
+
 handle_call({remove, Bucket}, _From, State) ->
 	case mnesia:delete_table(Bucket) of
 		{atomic, ok} -> {reply, ok, State};
@@ -558,6 +673,12 @@ handle_call({remove, Bucket, Node}, _From, State) ->
 		{aborted, Reason} -> {reply, {error, Reason}, State}
 	end;
 
+handle_call({replica, Bucket, Node, Type}, _From, State) ->
+	case mnesia:add_table_copy(Bucket, Node, Type) of
+		{atomic, _} -> {reply, ok, State};
+		{aborted, Reason} -> {reply, {error, Reason}, State}
+	end;
+
 handle_call({shrink, Bucket, Num}, _From, State) ->
 	case shrink_bucket(Bucket, Num) of
 		ok -> {reply, ok, State};