diff options
Diffstat (limited to 'src/rabbit_upgrade.erl')
| -rw-r--r-- | src/rabbit_upgrade.erl | 120 |
1 files changed, 69 insertions, 51 deletions
diff --git a/src/rabbit_upgrade.erl b/src/rabbit_upgrade.erl index 0071a08a..97a07514 100644 --- a/src/rabbit_upgrade.erl +++ b/src/rabbit_upgrade.erl @@ -32,11 +32,13 @@ -ifdef(use_specs). +-type(step() :: atom()). +-type(version() :: [step()]). + -spec(maybe_upgrade/0 :: () -> 'ok' | 'version_not_available'). --spec(read_version/0 :: - () -> {'ok', [any()]} | rabbit_types:error(any())). +-spec(read_version/0 :: () -> rabbit_types:ok_or_error2(version(), any())). -spec(write_version/0 :: () -> 'ok'). --spec(desired_version/0 :: () -> [atom()]). +-spec(desired_version/0 :: () -> version()). -endif. @@ -48,26 +50,25 @@ maybe_upgrade() -> case read_version() of {ok, CurrentHeads} -> - G = load_graph(), - case unknown_heads(CurrentHeads, G) of - [] -> - case upgrades_to_apply(CurrentHeads, G) of - [] -> ok; - Upgrades -> apply_upgrades(Upgrades) - end; - Unknown -> - exit({future_upgrades_found, Unknown}) - end, - true = digraph:delete(G), - ok; + with_upgrade_graph( + fun (G) -> + case unknown_heads(CurrentHeads, G) of + [] -> case upgrades_to_apply(CurrentHeads, G) of + [] -> ok; + Upgrades -> apply_upgrades(Upgrades) + end; + Unknown -> throw({error, + {future_upgrades_found, Unknown}}) + end + end); {error, enoent} -> version_not_available end. read_version() -> case rabbit_misc:read_term_file(schema_filename()) of - {ok, [Heads]} -> {ok, Heads}; - {error, E} -> {error, E} + {ok, [Heads]} -> {ok, Heads}; + {error, _} = Err -> Err end. write_version() -> @@ -75,17 +76,26 @@ write_version() -> ok. desired_version() -> - G = load_graph(), - Version = heads(G), - true = digraph:delete(G), - Version. + with_upgrade_graph(fun (G) -> heads(G) end). %% ------------------------------------------------------------------- -load_graph() -> - Upgrades = rabbit_misc:all_module_attributes(rabbit_upgrade), - rabbit_misc:build_acyclic_graph( - fun vertices/2, fun edges/2, fun graph_build_error/1, Upgrades). +with_upgrade_graph(Fun) -> + case rabbit_misc:build_acyclic_graph( + fun vertices/2, fun edges/2, + 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) -> [{StepName, {Module, StepName}} || {StepName, _Reqs} <- Steps]. @@ -93,10 +103,6 @@ vertices(Module, Steps) -> edges(_Module, Steps) -> [{Require, StepName} || {StepName, Requires} <- Steps, Require <- Requires]. -graph_build_error({vertex, duplicate, StepName}) -> - exit({duplicate_upgrade, StepName}); -graph_build_error({edge, E, From, To}) -> - exit({E, From, To}). unknown_heads(Heads, G) -> [H || H <- Heads, digraph:vertex(G, H) =:= false]. @@ -111,8 +117,8 @@ upgrades_to_apply(Heads, 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))]. + [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]). @@ -120,19 +126,35 @@ heads(G) -> %% ------------------------------------------------------------------- apply_upgrades(Upgrades) -> - LockFile = lock_filename(), - case file:open(LockFile, [write, exclusive]) of - {ok, Lock} -> - ok = file:close(Lock), + LockFile = lock_filename(dir()), + case rabbit_misc:lock_file(LockFile) of + ok -> + BackupDir = dir() ++ "-upgrade-backup", info("Upgrades: ~w to apply~n", [length(Upgrades)]), - [apply_upgrade(Upgrade) || Upgrade <- Upgrades], - info("Upgrades: All applied~n", []), - ok = write_version(), - ok = file:delete(LockFile); + case rabbit_mnesia:copy_db(BackupDir) of + ok -> + %% We need to make the backup after creating the + %% lock file so that it protects us from trying to + %% overwrite the backup. Unfortunately this means + %% the lock file exists in the backup too, which + %% is not intuitive. Remove it. + ok = file:delete(lock_filename(BackupDir)), + info("Upgrades: Mnesia dir backed up to ~p~n", [BackupDir]), + [apply_upgrade(Upgrade) || Upgrade <- Upgrades], + info("Upgrades: All upgrades applied successfully~n", []), + ok = write_version(), + ok = rabbit_misc:recursive_delete([BackupDir]), + info("Upgrades: Mnesia backup removed~n", []), + ok = file:delete(LockFile); + {error, E} -> + %% If we can't backup, the upgrade hasn't started + %% hence we don't need the lockfile since the real + %% mnesia dir is the good one. + ok = file:delete(LockFile), + throw({could_not_back_up_mnesia_dir, E}) + end; {error, eexist} -> - exit(previous_upgrade_failed); - {error, _} = Error -> - exit(Error) + throw({error, previous_upgrade_failed}) end. apply_upgrade({M, F}) -> @@ -141,16 +163,12 @@ apply_upgrade({M, F}) -> %% ------------------------------------------------------------------- -schema_filename() -> - filename:join(dir(), ?VERSION_FILENAME). +dir() -> rabbit_mnesia:dir(). -lock_filename() -> - filename:join(dir(), ?LOCK_FILENAME). +schema_filename() -> filename:join(dir(), ?VERSION_FILENAME). + +lock_filename(Dir) -> filename:join(Dir, ?LOCK_FILENAME). %% NB: we cannot use rabbit_log here since it may not have been %% started yet -info(Msg, Args) -> - error_logger:info_msg(Msg, Args). - -dir() -> - rabbit_mnesia:dir(). +info(Msg, Args) -> error_logger:info_msg(Msg, Args). |