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doc (cli/pubsub): document pubsub cache management commands
author Goffi <goffi@goffi.org>
date Thu, 29 Jul 2021 22:51:01 +0200
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children 23be54db81f1
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1 .. _libervia-cli_pubsub_cache:
2
3 =====================================
4 pubsub/cache: PubSub Cache Management
5 =====================================
6
7 Libervia runs transparently a cache for pubsub. That means that according to internal
8 criteria, some pubsub items are stored locally.
9
10 The ``cache`` subcommands let user inspect and manipulate the internal cache.
11
12 get
13 ===
14
15 Retrieve items from internal cache only. Most end-users won't need to use this command, as
16 the usual ``pubsub get`` command will use cache transparently. However, it may be useful
17 to inspect local cache, notably for debugging.
18
19 The parameters are basically the same as for :ref:`li_pubsub_get`.
20
21 example
22 -------
23
24 Retrieve the last 2 cached items for personal blog::
25
26 $ li pubsub cache get -n urn:xmpp:microblog:0 -M 2
27
28 .. _li_pubsub_cache_sync:
29
30 sync
31 ====
32
33 Synchronise or resynchronise a pubsub node. If the node is already in cache, it will be
34 deleted then re-cached. Node will be put in cache even if internal policy doesn't request
35 a synchronisation for this kind of nodes. Node will be (re-)subscribed to keep cache
36 synchronised.
37
38 All items of the node (up to the internal limit which is high), will be retrieved and put
39 in cache, even if a previous version of those items have been deleted by the
40 :ref:`li_pubsub_cache_purge` command.
41
42
43 example
44 -------
45
46 Resynchronise personal blog::
47
48 $ li pubusb cache sync -n urn:xmpp:microblog:0
49
50 .. _li_pubsub_cache_purge:
51
52 purge
53 =====
54
55 Remove items from cache. This may be desirable to save resource, notably disk space.
56
57 Note that once a pubsub node is cached, the cache is the source of trust. That means that
58 if cache is not explicitly bypassed when retrieving items of a pubsub node (notably with
59 the ``-C, --no-cache`` option of :ref:`li_pubsub_get`), only items found in cache will be
60 returned, thus purged items won't be used or returned anymore even if they still exists on
61 the original pubsub service.
62
63 If you have purged items by mistake, it is possible to retrieve them either node by node
64 using :ref:`li_pubsub_cache_sync`, or by resetting the whole pubsub cache with
65 :ref:`li_pubsub_cache_reset`.
66
67 If you have a node or a profile (e.g. a component) caching a lot of items frequently, you
68 may use this command using a scheduler like cron_.
69
70 .. _cron: https://en.wikipedia.org/wiki/Cron
71
72 examples
73 --------
74
75 Remove all blog and event items from cache if they haven't been updated since 6 months::
76
77 $ li pubsub cache purge -t blog -t event -b "6 months ago"
78
79 Remove items from profile ``ap_gateway`` if they have been created more that 2 months
80 ago::
81
82 $ li pubsub cache purge -p ap_gateway --created-before "2 months ago"
83
84 .. _li_pubsub_cache_reset:
85
86 reset
87 =====
88
89 Reset the whole pubsub cache. This means that all nodes and all them items will be removed
90 from cache. After this command, cache will be re-filled progressively as if it where a new
91 one.
92
93 example
94 -------
95
96 Reset the whole pubsub cache::
97
98 $ li pubsub cache reset