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%% @doc Service dependency management |
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-module(mongoose_service_deps). |
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-export([resolve_deps/1, sort_deps/1]). |
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-type service_list() :: mongoose_service:service_list(). |
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-type service_map() :: mongoose_service:service_map(). |
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%% @doc Add dependencies to the service map |
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-spec resolve_deps(service_map()) -> service_map(). |
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resolve_deps(Services) when is_map(Services) -> |
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resolve_deps(maps:to_list(Services), #{}). |
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-spec resolve_deps(service_list(), service_map()) -> service_map(). |
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resolve_deps([], Acc) -> |
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Acc; |
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resolve_deps([{Service, Opts} | Rest], Acc) -> |
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{DepsToResolve, NewAcc} = |
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case Acc of |
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#{Service := PreviousOpts} -> |
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{[], Acc#{Service => merge_opts(PreviousOpts, Opts)}}; |
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#{} -> |
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Deps = [{Dep, #{}} || Dep <- mongoose_service:get_deps(Service)], |
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{Deps, Acc#{Service => Opts}} |
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end, |
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resolve_deps(DepsToResolve ++ Rest, NewAcc). |
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%% Deps always have no options, so one argument has to be an empty map |
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merge_opts(#{}, Opts) -> Opts; |
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merge_opts(Opts, #{}) -> Opts. |
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%% @doc Sort services (which already include their dependencies) according to the dependency graph |
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-spec sort_deps(service_map()) -> service_list(). |
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sort_deps(Services) when is_map(Services) -> |
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DepsGraph = digraph:new([acyclic, private]), |
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try |
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[add_service_with_deps(Service, DepsGraph) || Service <- maps:keys(Services)], |
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[{Service, maps:get(Service, Services)} || Service <- digraph_utils:topsort(DepsGraph)] |
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after |
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digraph:delete(DepsGraph) |
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end. |
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add_service_with_deps(Service, DepsGraph) -> |
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digraph:add_vertex(DepsGraph, Service), |
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lists:foreach(fun(DepService) -> add_service_dep(Service, DepService, DepsGraph) end, |
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mongoose_service:get_deps(Service)). |
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add_service_dep(Service, DepService, DepsGraph) -> |
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digraph:add_vertex(DepsGraph, DepService), |
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case digraph:add_edge(DepsGraph, DepService, Service) of |
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{error, Error} -> |
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{bad_edge, CyclePath} = Error, |
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error(#{what => resolving_dependencies_aborted, |
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text => <<"Service dependency cycle found">>, |
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service => Service, |
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dep_service => DepService, |
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cycle_path => CyclePath}); |
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_Edge -> |
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ok |
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end. |