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Added a timeout value for the take_group_member #72

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Added a timeout value for the take_group_member #72

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30 changes: 23 additions & 7 deletions src/pooler.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
take_member/1,
take_member/2,
take_group_member/1,
take_group_member/2,
return_group_member/2,
return_group_member/3,
return_member/2,
Expand Down Expand Up @@ -202,13 +203,21 @@ take_member(PoolName) when is_atom(PoolName) orelse is_pid(PoolName) ->
take_member(PoolName, Timeout) when is_atom(PoolName) orelse is_pid(PoolName) ->
gen_server:call(PoolName, {take_member, time_as_millis(Timeout)}, infinity).


%% @doc Take a member from a randomly selected member of the group
%% `GroupName'. Returns `MemberPid' or `error_no_members'. If no
%% members are available in the randomly chosen pool, all other pools
%% in the group are tried in order.
-spec take_group_member(atom()) -> pid() | error_no_members | {error_no_group, atom()}.
take_group_member(GroupName) ->
take_group_member(GroupName) -> take_group_member(GroupName, 0).

%% @doc Take a member from a randomly selected member of the group
%% `GroupName'. Returns `MemberPid' or `error_no_members'. If no
%% members are available in the randomly chosen pool, all other pools
%% in the group are tried in order. If no member
%% is available within the specified timeout, error_no_members is returned.
%% `Timeout' can be either milliseconds as integer or `{duration, time_unit}'
-spec take_group_member(atom(), non_neg_integer()) -> pid() | error_no_members | {error_no_group, atom()}.
take_group_member(GroupName, Timeout) ->
case pg2:get_local_members(GroupName) of
{error, {no_such_group, GroupName}} ->
{error_no_group, GroupName};
Expand All @@ -220,18 +229,25 @@ take_group_member(GroupName) ->
{_, _, X} = os:timestamp(),
Idx = (X rem length(Pools)) + 1,
{PoolPid, Rest} = extract_nth(Idx, Pools),
take_first_pool([PoolPid | Rest])
case {take_first_pool([PoolPid | Rest], 0), Timeout} of
{error_no_members, 0} ->
error_no_members;
{error_no_members, _} ->
take_first_pool([PoolPid | Rest], Timeout);
{Member, _} ->
Member
end
end.

take_first_pool([PoolPid | Rest]) ->
case take_member(PoolPid) of
take_first_pool([PoolPid | Rest], Timeout) ->
case take_member(PoolPid, Timeout) of
error_no_members ->
take_first_pool(Rest);
take_first_pool(Rest, Timeout);
Member ->
ets:insert(?POOLER_GROUP_TABLE, {Member, PoolPid}),
Member
end;
take_first_pool([]) ->
take_first_pool([], _) ->
error_no_members.

%% this helper function returns `{Nth_Elt, Rest}' where `Nth_Elt' is
Expand Down