ffs_service.erl

% Copyright The OpenTelemetry Authors
%
% Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS,
% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
% See the License for the specific language governing permissions and
% limitations under the License.

-module(ffs_service).

-behaviour(ffs_service_bhvr).

-export([get_flag/2,
  create_flag/2,
  update_flag/2,
  list_flags/2,
  delete_flag/2]).

-include_lib("grpcbox/include/grpcbox.hrl").

-include_lib("opentelemetry_api/include/otel_tracer.hrl").

-spec get_flag(ctx:t(), ffs_demo_pb:get_flag_request()) ->
  {ok, ffs_demo_pb:get_flag_response(), ctx:t()} | grpcbox_stream:grpc_error_response().
get_flag(Ctx, #{name := Name}) ->
  case 'Elixir.Featureflagservice.FeatureFlags':get_feature_flag_by_name(Name) of
    nil ->
      {grpc_error, {?GRPC_STATUS_NOT_FOUND, <<"the requested feature flag does not exist">>}};
    #{'__struct__' := 'Elixir.Featureflagservice.FeatureFlags.FeatureFlag',
      description := Description,
      enabled := Enabled
    } ->
      RandomNumber = rand:uniform(100), % Generate a random number between 0 and 100
      Probability = trunc(Enabled * 100), % Convert the Enabled value to a percentage
      FlagEnabledValue = RandomNumber =< Probability, % Determine if the random number falls within the probability range

      ?set_attribute('app.featureflag.name', Name),
      ?set_attribute('app.featureflag.raw_value', Enabled),
      ?set_attribute('app.featureflag.enabled', FlagEnabledValue),

      Flag = #{name => Name,
        description => Description,
        enabled => FlagEnabledValue},

      {ok, #{flag => Flag}, Ctx}
  end.

-spec create_flag(ctx:t(), ffs_demo_pb:create_flag_request()) ->
  {ok, ffs_demo_pb:create_flag_response(), ctx:t()} | grpcbox_stream:grpc_error_response().
create_flag(_Ctx, _) ->
  {grpc_error, {?GRPC_STATUS_UNIMPLEMENTED, <<"use the web interface to create flags.">>}}.

-spec update_flag(ctx:t(), ffs_demo_pb:update_flag_request()) ->
  {ok, ffs_demo_pb:update_flag_response(), ctx:t()} | grpcbox_stream:grpc_error_response().
update_flag(_Ctx, _) ->
  {grpc_error, {?GRPC_STATUS_UNIMPLEMENTED, <<"use the web interface to update flags.">>}}.

-spec list_flags(ctx:t(), ffs_demo_pb:list_flags_request()) ->
  {ok, ffs_demo_pb:list_flags_response(), ctx:t()} | grpcbox_stream:grpc_error_response().
list_flags(_Ctx, _) ->
  {grpc_error, {?GRPC_STATUS_UNIMPLEMENTED, <<"use the web interface to view all flags.">>}}.

-spec delete_flag(ctx:t(), ffs_demo_pb:delete_flag_request()) ->
  {ok, ffs_demo_pb:delete_flag_response(), ctx:t()} | grpcbox_stream:grpc_error_response().
delete_flag(_Ctx, _) ->
  {grpc_error, {?GRPC_STATUS_UNIMPLEMENTED, <<"use the web interface to delete flags.">>}}.