| 1 |
|
%% @doc Service dependency management |
| 2 |
|
|
| 3 |
|
-module(mongoose_service_deps). |
| 4 |
|
|
| 5 |
|
-export([resolve_deps/1, sort_deps/1]). |
| 6 |
|
|
| 7 |
|
-type service_list() :: mongoose_service:service_list(). |
| 8 |
|
-type service_map() :: mongoose_service:service_map(). |
| 9 |
|
|
| 10 |
|
%% @doc Add dependencies to the service map |
| 11 |
|
-spec resolve_deps(service_map()) -> service_map(). |
| 12 |
|
resolve_deps(Services) when is_map(Services) -> |
| 13 |
16 |
resolve_deps(maps:to_list(Services), #{}). |
| 14 |
|
|
| 15 |
|
-spec resolve_deps(service_list(), service_map()) -> service_map(). |
| 16 |
|
resolve_deps([], Acc) -> |
| 17 |
16 |
Acc; |
| 18 |
|
resolve_deps([{Service, Opts} | Rest], Acc) -> |
| 19 |
16 |
{DepsToResolve, NewAcc} = |
| 20 |
|
case Acc of |
| 21 |
|
#{Service := PreviousOpts} -> |
| 22 |
:-( |
{[], Acc#{Service => merge_opts(PreviousOpts, Opts)}}; |
| 23 |
|
#{} -> |
| 24 |
16 |
Deps = [{Dep, #{}} || Dep <- mongoose_service:get_deps(Service)], |
| 25 |
16 |
{Deps, Acc#{Service => Opts}} |
| 26 |
|
end, |
| 27 |
16 |
resolve_deps(DepsToResolve ++ Rest, NewAcc). |
| 28 |
|
|
| 29 |
|
%% Deps always have no options, so one argument has to be an empty map |
| 30 |
:-( |
merge_opts(#{}, Opts) -> Opts; |
| 31 |
:-( |
merge_opts(Opts, #{}) -> Opts. |
| 32 |
|
|
| 33 |
|
%% @doc Sort services (which already include their dependencies) according to the dependency graph |
| 34 |
|
-spec sort_deps(service_map()) -> service_list(). |
| 35 |
|
sort_deps(Services) when is_map(Services) -> |
| 36 |
31 |
DepsGraph = digraph:new([acyclic, private]), |
| 37 |
31 |
try |
| 38 |
31 |
[add_service_with_deps(Service, DepsGraph) || Service <- maps:keys(Services)], |
| 39 |
31 |
[{Service, maps:get(Service, Services)} || Service <- digraph_utils:topsort(DepsGraph)] |
| 40 |
|
after |
| 41 |
31 |
digraph:delete(DepsGraph) |
| 42 |
|
end. |
| 43 |
|
|
| 44 |
|
add_service_with_deps(Service, DepsGraph) -> |
| 45 |
31 |
digraph:add_vertex(DepsGraph, Service), |
| 46 |
31 |
lists:foreach(fun(DepService) -> add_service_dep(Service, DepService, DepsGraph) end, |
| 47 |
|
mongoose_service:get_deps(Service)). |
| 48 |
|
|
| 49 |
|
add_service_dep(Service, DepService, DepsGraph) -> |
| 50 |
:-( |
digraph:add_vertex(DepsGraph, DepService), |
| 51 |
:-( |
case digraph:add_edge(DepsGraph, DepService, Service) of |
| 52 |
|
{error, Error} -> |
| 53 |
:-( |
{bad_edge, CyclePath} = Error, |
| 54 |
:-( |
error(#{what => resolving_dependencies_aborted, |
| 55 |
|
text => <<"Service dependency cycle found">>, |
| 56 |
|
service => Service, |
| 57 |
|
dep_service => DepService, |
| 58 |
|
cycle_path => CyclePath}); |
| 59 |
|
_Edge -> |
| 60 |
:-( |
ok |
| 61 |
|
end. |