./ct_report/coverage/mod_last_riak.COVER.html

1 %%%----------------------------------------------------------------------
2 %%% File : mod_last.erl
3 %%% Author : Pawel Pikula <pawel.pikula@erlang-solutions.com>
4 %%% Purpose : mod_last riak backend (XEP-0012)
5 %%%
6 %%%
7 %%% ejabberd, Copyright (C) 2002-2014 ProcessOne
8 %%% MongooseIM, Copyright (C) 2014 Erlang Solutions Ltd.
9 %%%
10 %%%----------------------------------------------------------------------
11
12 %%% @doc Riak backend for last activity XEP
13 %%%
14 %%% The backend uses the existing riak connection pool, which is "globally" defined in
15 %%% the mongooseim.toml file. Therefore, we don't need to start anything in the init
16 %%% function.
17 %%%
18 %%% The module follows the approach taken by the other riak backends - it creates
19 %%% the following bucket `{<<"last">>, <<"example.com">>}' for each xmpp domain.
20 %%% The `<<"last">>' bucket type has the following props: `{"props":{"last_write_wins":true}}'
21 %%%
22 %%% Basically, there are 3 operations the backend need to provide set/get and count
23 %%% the number of users which has been active since given date. However, the count
24 %%% query can be only called using `mongooseimctl'.
25 %%%
26 %%% Username is used as a key and the value is just a user status, which is just
27 %%% a binary. Moreover, we have a secondary integer index on the timestamp, which
28 %%% is used in the count active users query.
29 %%%
30 %%% ```
31 %%% Data Layout:
32 %%% KV: {Username:binary, Status:binary}
33 %%% 2i: [Timestamp:integer]
34 %%% '''
35 %%%
36 %%% Set/Get are rather simple operations - they map to riak's put/get functions.
37 %%% The count query uses mapred task to calculate the number of users satisfying
38 %%% the criteria. As the input timestamp index range is used. The approach is
39 %%% described here: http://docs.basho.com/riak/latest/dev/using/2i/#Querying
40 %%% in the *Count Bucket Objects via $bucket Index* section. The alternative approach
41 %%% could be the "riakc_pb_socket:get_index_range" function
42 %%%
43 %%% The pros and cons of the both approaches have been discussed here:
44 %%% https://github.com/esl/MongooseIM/pull/567
45 %%% @end
46 -module(mod_last_riak).
47
48 -behaviour(mod_last_backend).
49
50 -include("mongoose.hrl").
51
52 -define(TIMESTAMP_IDX, {integer_index, "timestamp"}).
53
54 %% API
55 -export([init/2,
56 get_last/3,
57 count_active_users/3,
58 set_last_info/5,
59 remove_user/3,
60 remove_domain/2]).
61
62 -type host_type() :: mongooseim:host_type().
63
64 -spec init(host_type(), gen_mod:module_opts()) -> ok.
65 init(_VHost, _Opts) ->
66 %% we are using common riak pool
67 
:-(
 ok.
68
69 -spec get_last(host_type(), jid:luser(), jid:lserver()) ->
70 {ok, mod_last:timestamp(), mod_last:status()} | {error, term()} | not_found.
71 get_last(HostType, LUser, LServer) ->
72 
:-(
 case mongoose_riak:get(bucket_type(HostType, LServer), LUser) of
73 {ok, Obj} ->
74 
:-(
 Status = riakc_obj:get_value(Obj),
75 
:-(
 MD = riakc_obj:get_update_metadata(Obj),
76 
:-(
 [Timestamp] = riakc_obj:get_secondary_index(MD, ?TIMESTAMP_IDX),
77 
:-(
 {ok, Timestamp, Status};
78 {error, notfound} ->
79 
:-(
 not_found;
80 {error, Reason} ->
81 
:-(
 {error, Reason}
82 end.
83
84 -spec count_active_users(host_type(), jid:lserver(), mod_last:timestamp()) -> non_neg_integer().
85 count_active_users(HostType, LServer, TimeStamp) ->
86 
:-(
 Idx = {index, bucket_type(HostType, LServer), ?TIMESTAMP_IDX, TimeStamp+1, infinity()},
87 
:-(
 RedMF = {modfun, riak_kv_mapreduce, reduce_count_inputs},
88 
:-(
 Red = [{reduce, RedMF, [{reduce_phase_batch_size, 1000}], true}],
89 
:-(
 {ok, [{0, [Count]}]} = mongoose_riak:mapred(Idx, Red),
90 
:-(
 Count.
91
92 -spec set_last_info(host_type(), jid:luser(), jid:lserver(),
93 mod_last:timestamp(), mod_last:status()) ->
94 ok | {error, term()}.
95 set_last_info(HostType, LUser, LServer, Timestamp, Status) ->
96 
:-(
 Obj = riakc_obj:new(bucket_type(HostType, LServer), LUser, Status),
97 
:-(
 MD = riakc_obj:get_update_metadata(Obj),
98 
:-(
 MDWithIndex = riakc_obj:set_secondary_index(MD, [{?TIMESTAMP_IDX, [Timestamp]}]),
99 
:-(
 FinalObj = riakc_obj:update_metadata(Obj, MDWithIndex),
100
101 
:-(
 mongoose_riak:put(FinalObj).
102
103 -spec remove_user(host_type(), jid:luser(), jid:lserver()) -> ok | {error, term()}.
104 remove_user(HostType, LUser, LServer) ->
105 
:-(
 mongoose_riak:delete(bucket_type(HostType, LServer), LUser).
106
107 % Implementation only for RDBMS backends
108 -spec remove_domain(host_type(), jid:lserver()) -> ok.
109 remove_domain(_HostType, _Domain) ->
110 
:-(
 ok.
111
112 -spec bucket_type(host_type(), jid:lserver()) -> riakc_obj:bucket().
113 bucket_type(HostType, LServer) ->
114 
:-(
 {gen_mod:get_module_opt(HostType, mod_last, [riak, bucket_type]), LServer}.
115
116 -spec infinity() -> non_neg_integer().
117 infinity() ->
118 % almost infinity ... Wed, 16 Nov 5138 09:46:39 GMT
119 % I think Mongoose won't live so long ;)
120 
:-(
 99999999999.
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