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src/prometheus_sup.erl

-module(prometheus_sup).
-compile({parse_transform, prometheus_pt}).
-moduledoc false.
-export([start_link/0]).
-export([init/1]).
-export([register_metrics/1]).
-behaviour(supervisor).
-include("prometheus.hrl").
-spec start_link() -> supervisor:startlink_ret().
start_link() ->
supervisor:start_link({local, ?MODULE}, ?MODULE, []).
-spec init([]) -> {ok, {supervisor:sup_flags(), [supervisor:child_spec()]}}.
init([]) ->
create_tables(),
register_collectors(),
register_metrics(),
setup_instrumenters(),
{ok, {{one_for_one, 5, 1}, []}}.
%%====================================================================
%% Private Parts
%%====================================================================
create_tables() ->
Tables = [
{?PROMETHEUS_REGISTRY_TABLE, {bag, read_concurrency}},
{?PROMETHEUS_COUNTER_TABLE, write_concurrency},
{?PROMETHEUS_GAUGE_TABLE, write_concurrency},
{?PROMETHEUS_SUMMARY_TABLE, write_concurrency},
{?PROMETHEUS_QUANTILE_SUMMARY_TABLE, write_concurrency},
{?PROMETHEUS_HISTOGRAM_TABLE, write_concurrency},
{?PROMETHEUS_BOOLEAN_TABLE, write_concurrency}
],
[maybe_create_table(Name, Concurrency) || {Name, Concurrency} <- Tables],
ok.
register_collectors() ->
Collectors = prometheus_collector:enabled_collectors(),
prometheus_registry:register_collectors(Collectors).
register_metrics() ->
[declare_metric(Decl) || Decl <- default_metrics()].
-spec register_metrics([term()]) -> [boolean()].
register_metrics(Metrics) ->
DefaultMetrics0 = default_metrics(),
DefaultMetrics1 = lists:usort(DefaultMetrics0 ++ Metrics),
application:set_env(prometheus, default_metrics, DefaultMetrics1),
[declare_metric(Decl) || Decl <- Metrics].
setup_instrumenters() ->
[
prometheus_instrumenter:setup(Instrumenter)
|| Instrumenter <- prometheus_instrumenter:enabled_instrumenters()
].
default_metrics() ->
application:get_env(prometheus, default_metrics, []).
maybe_create_table(Name, {Type, Concurrency}) ->
case ets:info(Name) of
undefined ->
ets:new(Name, [Type, named_table, public, {Concurrency, true}]);
_ ->
ok
end;
maybe_create_table(Name, Concurrency) ->
maybe_create_table(Name, {set, Concurrency}).
declare_metric({Metric, Spec}) ->
declare_metric(Metric, Spec);
declare_metric({Registry, Metric, Spec}) ->
declare_metric(Metric, [{registry, Registry}] ++ Spec).
declare_metric(counter, Spec) ->
prometheus_counter:declare(Spec);
declare_metric(gauge, Spec) ->
prometheus_gauge:declare(Spec);
declare_metric(summary, Spec) ->
prometheus_summary:declare(Spec);
declare_metric(histogram, Spec) ->
prometheus_histogram:declare(Spec);
declare_metric(boolean, Spec) ->
prometheus_boolean:declare(Spec);
declare_metric(Other, Spec) ->
Other:declare(Spec).