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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License
%% at http://www.mozilla.org/MPL/
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and
%% limitations under the License.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developer of the Original Code is VMware, Inc.
%% Copyright (c) 2007-2011 VMware, Inc. All rights reserved.
%%
-module(rabbit_version).
-export([recorded/0, matches/2, desired/0, desired_for_scope/1,
record_desired/0, record_desired_for_scope/1,
upgrades_required/1]).
%% -------------------------------------------------------------------
-ifdef(use_specs).
-export_type([scope/0, step/0]).
-type(scope() :: atom()).
-type(scope_version() :: [atom()]).
-type(step() :: {atom(), atom()}).
-type(version() :: [atom()]).
-spec(recorded/0 :: () -> rabbit_types:ok_or_error2(version(), any())).
-spec(matches/2 :: ([A], [A]) -> boolean()).
-spec(desired/0 :: () -> version()).
-spec(desired_for_scope/1 :: (scope()) -> scope_version()).
-spec(record_desired/0 :: () -> 'ok').
-spec(record_desired_for_scope/1 ::
(scope()) -> rabbit_types:ok_or_error(any())).
-spec(upgrades_required/1 ::
(scope()) -> rabbit_types:ok_or_error2([step()], any())).
-endif.
%% -------------------------------------------------------------------
-define(VERSION_FILENAME, "schema_version").
-define(SCOPES, [mnesia, local]).
%% -------------------------------------------------------------------
recorded() -> case rabbit_file:read_term_file(schema_filename()) of
{ok, [V]} -> {ok, V};
{error, _} = Err -> Err
end.
record(V) -> ok = rabbit_file:write_term_file(schema_filename(), [V]).
recorded_for_scope(Scope) ->
case recorded() of
{error, _} = Err ->
Err;
{ok, Version} ->
{ok, case lists:keysearch(Scope, 1, categorise_by_scope(Version)) of
false -> [];
{value, {Scope, SV1}} -> SV1
end}
end.
record_for_scope(Scope, ScopeVersion) ->
case recorded() of
{error, _} = Err ->
Err;
{ok, Version} ->
Version1 = lists:keystore(Scope, 1, categorise_by_scope(Version),
{Scope, ScopeVersion}),
ok = record([Name || {_Scope, Names} <- Version1, Name <- Names])
end.
%% -------------------------------------------------------------------
matches(VerA, VerB) ->
lists:usort(VerA) =:= lists:usort(VerB).
%% -------------------------------------------------------------------
desired() -> [Name || Scope <- ?SCOPES, Name <- desired_for_scope(Scope)].
desired_for_scope(Scope) -> with_upgrade_graph(fun heads/1, Scope).
record_desired() -> record(desired()).
record_desired_for_scope(Scope) ->
record_for_scope(Scope, desired_for_scope(Scope)).
upgrades_required(Scope) ->
case recorded_for_scope(Scope) of
{error, enoent} ->
{error, version_not_available};
{ok, CurrentHeads} ->
with_upgrade_graph(
fun (G) ->
case unknown_heads(CurrentHeads, G) of
[] -> {ok, upgrades_to_apply(CurrentHeads, G)};
Unknown -> {error, {future_upgrades_found, Unknown}}
end
end, Scope)
end.
%% -------------------------------------------------------------------
with_upgrade_graph(Fun, Scope) ->
case rabbit_misc:build_acyclic_graph(
fun (Module, Steps) -> vertices(Module, Steps, Scope) end,
fun (Module, Steps) -> edges(Module, Steps, Scope) end,
rabbit_misc:all_module_attributes(rabbit_upgrade)) of
{ok, G} -> try
Fun(G)
after
true = digraph:delete(G)
end;
{error, {vertex, duplicate, StepName}} ->
throw({error, {duplicate_upgrade_step, StepName}});
{error, {edge, {bad_vertex, StepName}, _From, _To}} ->
throw({error, {dependency_on_unknown_upgrade_step, StepName}});
{error, {edge, {bad_edge, StepNames}, _From, _To}} ->
throw({error, {cycle_in_upgrade_steps, StepNames}})
end.
vertices(Module, Steps, Scope0) ->
[{StepName, {Module, StepName}} || {StepName, Scope1, _Reqs} <- Steps,
Scope0 == Scope1].
edges(_Module, Steps, Scope0) ->
[{Require, StepName} || {StepName, Scope1, Requires} <- Steps,
Require <- Requires,
Scope0 == Scope1].
unknown_heads(Heads, G) ->
[H || H <- Heads, digraph:vertex(G, H) =:= false].
upgrades_to_apply(Heads, G) ->
%% Take all the vertices which can reach the known heads. That's
%% everything we've already applied. Subtract that from all
%% vertices: that's what we have to apply.
Unsorted = sets:to_list(
sets:subtract(
sets:from_list(digraph:vertices(G)),
sets:from_list(digraph_utils:reaching(Heads, G)))),
%% Form a subgraph from that list and find a topological ordering
%% so we can invoke them in order.
[element(2, digraph:vertex(G, StepName)) ||
StepName <- digraph_utils:topsort(digraph_utils:subgraph(G, Unsorted))].
heads(G) ->
lists:sort([V || V <- digraph:vertices(G), digraph:out_degree(G, V) =:= 0]).
%% -------------------------------------------------------------------
categorise_by_scope(Version) when is_list(Version) ->
Categorised =
[{Scope, Name} || {_Module, Attributes} <-
rabbit_misc:all_module_attributes(rabbit_upgrade),
{Name, Scope, _Requires} <- Attributes,
lists:member(Name, Version)],
orddict:to_list(
lists:foldl(fun ({Scope, Name}, CatVersion) ->
rabbit_misc:orddict_cons(Scope, Name, CatVersion)
end, orddict:new(), Categorised)).
dir() -> rabbit_mnesia:dir().
schema_filename() -> filename:join(dir(), ?VERSION_FILENAME).
|
