1nameserv::auto(n) Name service facility nameserv::auto(n)
2______________________________________________________________________________
6
8 nameserv::auto - Name service facility, Client Extension
9
11 package require Tcl 8.4
12 package require nameserv::auto ?0.3?
14 package require nameserv
16_________________________________________________________________
18
20 Please read the document Name service facility, introduction first.
21 This package provides the exact same API as is provided by package
23 nameserv, i.e the regular name service client. It differs from the for‐
24 mer by taking measures to ensure that longer-lived data, i.e. bound
25 names, continuous and unfulfilled async searches, survive the loss of
26 the connection to the name server as much as is possible.
27 This means that the bound names and continuous and unfulfilled async
29 searches are remembered client-side and automatically re-entered into
30 the server when the connection comes back after its loss. For bound
31 names there is one important limitation to such restoration: It is pos‐
32 sible that a name of this client was bound by a different client while
33 the connection was gone. Such names are fully lost, and the best the
34 package can and will do is to inform the user of this.
35
37 The user-visible API is mainly identical the API of nameserv and is
38 therefore not described here. Please read the documentation of name‐
39 serv.
40 The differences are explained in the sections OPTIONS and EVENTS.
42
44 This package supports all the option of package nameserv, and one more.
45 The additional option allows the user to specifies the time interval
46 between attempts to restore a lost connection.
47 -delay milliseconds
49 The value of this option is an integer value > 0 which specifies
50 the interval to wait between attempts to restore a lost connec‐
51 tion, in milliseconds. The default value is 1000, i.e. one sec‐
52 ond.
53
55 This package generates all of the events of package nameserv, and two
56 more. Both events are generated for the tag nameserv.
57 lost-name
59 This event is generated when a bound name is truly lost, i.e.
60 could not be restored after the temporary loss of the connection
61 to the name server. It indicates that a different client took
62 ownership of the name while this client was out of contact.
63 The detail information of the event will be a Tcl dictionary
65 containing two keys, name, and data. Their values hold all the
66 information about the lost name.
67 re-connection
69 This event is generated when the connection to the server is
70 restored. The remembered data has been restored when the event
71 is posted.
72 The event has no detail information.
74
76 The package is implemented on top of the regular nameservice client,
77 i.e. package nameserv. It detects the loss of the connection by lis‐
78 tening for lost-connection events, on the tag nameserv.
79 It reacts to such events by starting a periodic timer and trying to
81 reconnect to the server whenver this timer triggers. On success the
82 timer is canceled, a re-connection event generated, and the package
83 proceeds to re-enter the remembered bound names and continous searches.
84 Another loss of the connection, be it during or after re-entering the
86 remembered information simply restarts the timer and subsequent recon‐
87 nection attempts.
88
90 This document, and the package it describes, will undoubtedly contain
91 bugs and other problems. Please report such in the category nameserv
92 of the Tcllib SF Trackers [http://source‐
93 forge.net/tracker/?group_id=12883]. Please also report any ideas for
94 enhancements you may have for either package and/or documentation.
95
97 nameserv(n)
98
100 automatic, client, name service, reconnect, restore
101
103 Copyright (c) 2007-2008 Andreas Kupries <andreas_kupries@users.sourceforge.net>
104nns 0.3 nameserv::auto(n)