prosody
a698f65df453
plugins/mod_tombstones.lua

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plugins/mod_tombstones.lua @ 12438:a698f65df453 0.12

mod_tombstones: Add caching to improve performance on busy servers (fixes #1728)
author Matthew Wild <mwild1@gmail.com>
date Mon, 28 Mar 2022 11:08:18 +0100
parent 12117:0c9b64178eda
child 12977:74b9e05af71e
comparison
equal deleted inserted replaced
12437:9f5d0b77e3df 12438:a698f65df453
1 -- TODO warn when trying to create an user before the tombstone expires 1 -- TODO warn when trying to create an user before the tombstone expires
2 -- e.g. via telnet or other admin interface 2 -- e.g. via telnet or other admin interface
3 local datetime = require "util.datetime"; 3 local datetime = require "util.datetime";
4 local errors = require "util.error"; 4 local errors = require "util.error";
5 local jid_split = require"util.jid".split; 5 local jid_node = require"util.jid".node;
6 local st = require "util.stanza"; 6 local st = require "util.stanza";
7 7
8 -- Using a map store as key-value store so that removal of all user data 8 -- Using a map store as key-value store so that removal of all user data
9 -- does not also remove the tombstone, which would defeat the point 9 -- does not also remove the tombstone, which would defeat the point
10 local graveyard = module:open_store(nil, "map"); 10 local graveyard = module:open_store(nil, "map");
11 local graveyard_cache = require "util.cache".new(module:get_option_number("tombstone_cache_size", 1024));
11 12
12 local ttl = module:get_option_number("user_tombstone_expiry", nil); 13 local ttl = module:get_option_number("user_tombstone_expiry", nil);
13 -- Keep tombstones forever by default 14 -- Keep tombstones forever by default
14 -- 15 --
15 -- Rationale: 16 -- Rationale:
27 end 28 end
28 end); 29 end);
29 30
30 -- Public API 31 -- Public API
31 function has_tombstone(username) 32 function has_tombstone(username)
32 local tombstone, err = graveyard:get(nil, username); 33 local tombstone;
33 34
34 if err or not tombstone then return tombstone, err; end 35 -- Check cache
36 local cached_result = graveyard_cache:get(username);
37 if cached_result == false then
38 -- We cached that there is no tombstone for this user
39 return false;
40 elseif cached_result then
41 tombstone = cached_result;
42 else
43 local stored_result, err = graveyard:get(nil, username);
44 if not stored_result and not err then
45 -- Cache that there is no tombstone for this user
46 graveyard_cache:set(username, false);
47 return false;
48 elseif err then
49 -- Failed to check tombstone status
50 return nil, err;
51 end
52 -- We have a tombstone stored, so let's continue with that
53 tombstone = stored_result;
54 end
35 55
56 -- Check expiry
36 if ttl and tombstone + ttl < os.time() then 57 if ttl and tombstone + ttl < os.time() then
37 module:log("debug", "Tombstone for %s created at %s has expired", username, datetime.datetime(tombstone)); 58 module:log("debug", "Tombstone for %s created at %s has expired", username, datetime.datetime(tombstone));
38 graveyard:set(nil, username, nil); 59 graveyard:set(nil, username, nil);
60 graveyard_cache:set(username, nil); -- clear cache entry (if any)
39 return nil; 61 return nil;
40 end 62 end
63
64 -- Cache for the future
65 graveyard_cache:set(username, tombstone);
66
41 return tombstone; 67 return tombstone;
42 end 68 end
43 69
44 module:hook("user-registering", function(event) 70 module:hook("user-registering", function(event)
45 local tombstone, err = has_tombstone(event.username); 71 local tombstone, err = has_tombstone(event.username);
57 return true; 83 return true;
58 end); 84 end);
59 85
60 module:hook("presence/bare", function(event) 86 module:hook("presence/bare", function(event)
61 local origin, presence = event.origin, event.stanza; 87 local origin, presence = event.origin, event.stanza;
88 local local_username = jid_node(presence.attr.to);
89 if not local_username then return; end
62 90
63 -- We want to undo any left-over presence subscriptions and notify the former 91 -- We want to undo any left-over presence subscriptions and notify the former
64 -- contact that they're gone. 92 -- contact that they're gone.
65 -- 93 --
66 -- FIXME This leaks that the user once existed. Hard to avoid without keeping 94 -- FIXME This leaks that the user once existed. Hard to avoid without keeping
67 -- the contact list in some form, which we don't want to do for privacy 95 -- the contact list in some form, which we don't want to do for privacy
68 -- reasons. Bloom filter perhaps? 96 -- reasons. Bloom filter perhaps?
69 if has_tombstone(jid_split(presence.attr.to)) then 97
70 if presence.attr.type == "probe" then 98 local pres_type = presence.attr.type;
71 origin.send(st.error_reply(presence, "cancel", "gone", "User deleted")); 99 local is_probe = pres_type == "probe";
72 origin.send(st.presence({ type = "unsubscribed"; to = presence.attr.from; from = presence.attr.to })); 100 local is_normal = pres_type == nil or pres_type == "unavailable";
73 elseif presence.attr.type == nil or presence.attr.type == "unavailable" then 101 if is_probe and has_tombstone(local_username) then
74 origin.send(st.error_reply(presence, "cancel", "gone", "User deleted")); 102 origin.send(st.error_reply(presence, "cancel", "gone", "User deleted"));
75 origin.send(st.presence({ type = "unsubscribe"; to = presence.attr.from; from = presence.attr.to })); 103 origin.send(st.presence({ type = "unsubscribed"; to = presence.attr.from; from = presence.attr.to }));
76 end 104 return true;
105 elseif is_normal and has_tombstone(local_username) then
106 origin.send(st.error_reply(presence, "cancel", "gone", "User deleted"));
107 origin.send(st.presence({ type = "unsubscribe"; to = presence.attr.from; from = presence.attr.to }));
77 return true; 108 return true;
78 end 109 end
79 end, 1); 110 end, 1);