| 1 |
|
-module(mod_bosh_mnesia). |
| 2 |
|
|
| 3 |
|
-behaviour(mod_bosh_backend). |
| 4 |
|
|
| 5 |
|
%% mod_bosh_backend callbacks |
| 6 |
|
-export([start/0, |
| 7 |
|
create_session/1, |
| 8 |
|
delete_session/1, |
| 9 |
|
get_session/1, |
| 10 |
|
get_sessions/0, |
| 11 |
|
node_cleanup/1]). |
| 12 |
|
|
| 13 |
|
-include("mod_bosh.hrl"). |
| 14 |
|
|
| 15 |
|
-spec start() -> any(). |
| 16 |
|
start() -> |
| 17 |
101 |
mongoose_mnesia:create_table(bosh_session, |
| 18 |
|
[{ram_copies, [node()]}, |
| 19 |
|
{attributes, record_info(fields, bosh_session)}]). |
| 20 |
|
|
| 21 |
|
%% The choice of the operation context here (transaction vs dirty, |
| 22 |
|
%% see man on mnesia:activity/4 for description of contexts) and the deletion |
| 23 |
|
%% in delete_session/1 below depends on the availability of a load balancer |
| 24 |
|
%% capable of doing server/session affiliation. |
| 25 |
|
%% |
| 26 |
|
%% With affiliation, it suffices for this write to be synchronous, since the |
| 27 |
|
%% client can issue no subsequent request without a session ID and the ID is |
| 28 |
|
%% returned to the client only after the dirty synchronous write returns. |
| 29 |
|
%% Other nodes in the cluster eventually will have the current view of the |
| 30 |
|
%% database, possibly (significantly) later than the write returns. However, |
| 31 |
|
%% the only node serving the client in question always operates on valid data. |
| 32 |
|
%% |
| 33 |
|
%% Without affiliation, each BOSH/HTTP request may be handled by a different |
| 34 |
|
%% node in the cluster. Hence, we must guarantee that once the write |
| 35 |
|
%% operation returns, all nodes in the cluster will have access to currently |
| 36 |
|
%% valid data -- that's why a transaction is used instead of a dirty write. |
| 37 |
|
|
| 38 |
|
-spec create_session(mod_bosh:session()) -> any(). |
| 39 |
|
create_session(#bosh_session{} = Session) -> |
| 40 |
126 |
mnesia:sync_transaction(fun mnesia:write/1, [Session]). |
| 41 |
|
|
| 42 |
|
|
| 43 |
|
-spec delete_session(mod_bosh:sid()) -> any(). |
| 44 |
|
delete_session(Sid) -> |
| 45 |
126 |
mnesia:transaction(fun mnesia:delete/1, [{bosh_session, Sid}]). |
| 46 |
|
|
| 47 |
|
|
| 48 |
|
-spec get_session(mod_bosh:sid()) -> [mod_bosh:session()]. |
| 49 |
|
get_session(Sid) -> |
| 50 |
1910 |
mnesia:dirty_read(bosh_session, Sid). |
| 51 |
|
|
| 52 |
|
|
| 53 |
|
-spec get_sessions() -> [mod_bosh:session()]. |
| 54 |
|
get_sessions() -> |
| 55 |
121 |
mnesia:dirty_match_object(mnesia:table_info(bosh_session, wild_pattern)). |
| 56 |
|
|
| 57 |
|
-spec node_cleanup(atom()) -> any(). |
| 58 |
|
node_cleanup(Node) -> |
| 59 |
7 |
F = fun() -> |
| 60 |
7 |
SIDs = mnesia:select( |
| 61 |
|
bosh_session, |
| 62 |
|
[{#bosh_session{sid = '$1', socket = '$2'}, |
| 63 |
|
[{'==', {node, '$2'}, Node}], |
| 64 |
|
['$1']}]), |
| 65 |
7 |
lists:foreach(fun(SID) -> |
| 66 |
:-( |
mnesia:delete({bosh_session, SID}) |
| 67 |
|
end, SIDs) |
| 68 |
|
end, |
| 69 |
7 |
mnesia:async_dirty(F). |
| 70 |
|
|