4 innduct \- quickly and reliably stream Usenet articles to remote site
12 implements NNTP peer-to-peer news transmission including the streaming
13 extensions, for sending news articles to a remote site. It is
14 intended as a replacement for
21 You need to run one instance of innduct for each peer site. innduct
22 manages its interaction with
24 including flushing the feed as appropriate, etc., so that articles are
25 transmitted quickly, and manages the retransmission of its own
26 backlog. innduct includes the locking necessary to avoid multiple
27 simutaneous invocations.
29 By default, innduct reads the default feedfile corresponding to
33 .IR pathoutgoing / site )
34 and feeds it via NNTP, streaming if possible, to the host
38 is not specified, it defaults to
41 innduct daemonises after argument parsing, and all logging (including
42 error messages) are sent to syslog (facility
45 The best way to run innduct is probably to periodically invoke it
46 for each feed (e.g. from cron), passing the
48 option to arrange that innduct silently exits if an instance is
49 already running for that site.
52 .BR \-f | \-\-feedfile= \fIDIR\fR / |\fIPATH\fR
55 to read, and indirectly specifies the paths to
56 be used for various associated files (see FILES, below).
59 it is taken as a directory to use, and the actual feed file used is
67 it is taken to be relative to
73 .BR \-q | \-\-quiet-multiple
74 Makes innduct silently exit (with status 0) if another innduct holds
75 the lock for the site. Without \fB-q\fR, this causes a fatal error to
76 be logged and a nonzero exit.
79 Do not daemonise. innduct runs in the foreground, but otherwise
80 operates normally (logging to syslog, etc.).
83 Do not daemonise. innduct runs in the foreground and all messages
84 (including all debug messages) are written to stderr rather than
85 syslog. A control command line is also available on stdin/stdout.
88 Do not try to use the streaming extensions to NNTP (for use eg if the
89 peer can't cope when we send MODE STREAM).
92 Do not try to use the file change monitoring support to watch for
93 writes by innd to the feed file; poll it instead. (If file monitoring
94 is not compiled in, this option just downgrades the log message which
95 warns about this situation.)
97 .BR \-C | \-\-inndconf= \fIFILE\fR
100 instead of the default
106 at the remote site rather than to the NNTP port (119).
108 .BI \-\-chdir= PATHRUN
111 at startup. The default is
115 .BR \-\-cli= \fICLI-DIR\fR / |\fICLI-PATH\fR| none
116 Listen for control command line connections on
118 (if the value ends with a
122 (if it doesn't). See CONTROLLING INNDUCT, below.
123 Note that there is a fairly short limit on the lengths of AF_UNIX
124 socket pathnames. If specified as
126 the directory will be created with mode 700 if necessary.
129 which means to create that directory in
132 .RB \fIPATHRUN\fR /innduct/ \fIsite\fR.
135 Just print a brief usage message and list of the options to stdout.
137 See TUNING OPTIONS below for more options.
138 .SH CONTROLLING INNDUCT
139 If you tell innd to drop the feed, innduct will (when it notices,
140 which will normally be the next time it decides to flush) finish up the
141 articles it has in hand now, and then exit. It is harmless to cause
142 innd to flush the feed (but innduct won't notice and flushing won't
143 start a new feedfile; you have to leave that to innduct).
145 If you want to stop innduct you can send it SIGTERM or SIGINT, or the
147 control command, in which case it will report statistics so far and
148 quickly exit. If innduct receives SIGKILL nothing will be broken or
149 corrupted; you just won't see some of the article stats.
151 innduct listens on an AF_UNIX socket (by default,
152 .IR pathrun \fB/innduct/\fR site ),
153 and provides a command-line interface which can be used to trigger
154 various events and for debugging. When a connection arrives, innduct
155 writes a prompt, reads commands a line at a time, and writes any
156 output back to the caller. (Everything uses unix line endings.) The
157 cli can most easily be accessed with a program like
161 .RI \fB/var/run/news/innduct/\fR site )
167 The following control commands are supported:
170 Print a list of all the commands understood. This list includes
171 undocumented commands which mess with innduct's internal state and
172 should only be used by a developer in conjuction with the innduct
176 Start a new feed file and trigger a flush of the feed. (Or, cause
178 .I FLUSH-FINISH-PERIOD
179 to expire early, forcibly completing a previously started flush.)
182 Log statistics and exit. (Same effect as SIGTERM or SIGINT.)
185 Log statistics so far and zero the stats counters. Stats are also
186 logged periodically, when an input file is completed and just before
190 Writes summary information about innduct's state to the current CLI
194 Writes the same information about innduct's state to a plain text file
195 .IR feedfile \fB_dump\fR.
196 This overwrites any previous dump. innduct does not ever delete these
199 gives a summary including general state and a list of connections;
201 also includes information about each article innduct is dealing with.
204 Requests that innduct rescan for new backlog files at the next
206 poll. Normally innduct assumes that any backlog files dropped in by
207 the administrator are not urgent, and it may not get around to
209 .IR BACKLOG-SCAN-PERIOD .
212 Resets the connection startup delay counter so that innduct may
213 consider making a new connection to the peer right away, regardless
215 .IR RECONNECT-PERIOD .
216 A connection attempt will still only be made if innduct feels that it
217 needs one, and innduct may wait up to
219 before actually starting the attempt.
221 You should not normally need to adjust these. Time intervals may
222 specified in seconds, or as a number followed by one of the following
225 .BR "sec min hour day" ,
228 .BI \-\-max-connections= max
229 Restricts the maximum number of simultaneous NNTP connections
232 There is no global limit on the number of connections used by all
233 innducts, as the instances for different sites are entirely
238 .BI \-\-max-queue-per-conn= per-conn-max
239 Restricts the maximum number of outstanding articles queued on any
240 particular connection to
242 (Non-streaming connections can only handle one article at a time.)
246 .BI \-\-max-queue-per-file= max
247 Restricts the maximum number articles read into core from any one
254 .BI \-\-feedfile-flush-size= bytes
255 Specifies that innduct should flush the feed and start a new feedfile
256 when the existing feedfile size exceeds
258 the effect is that the innduct will try to avoid the various
259 batchfiles growing much beyond this size. The default is
262 .BI \-\-period-interval= PERIOD-INTERVAL
263 Specifies wakup interval and period granularity.
264 innduct wakes up every
266 to do various housekeeping checks. Also, many of the timeout and
267 rescan intervals (those specified in this manual as
269 are rounded up to the next multiple of
270 .IR PERIOD-INTERVAL .
274 .BI \-\-connection-timeout= TIME
275 How long to allow for a connection setup attempt before giving up.
279 .BI \-\-stuck-flush-timeout= TIME
280 How long to wait for innd to respond to a flush request before giving
284 .BI \-\-feedfile-poll= TIME
285 How often to poll the feedfile for new articles written by innd
288 or equivalent) is not available. (When file monitoring is available,
289 there is no need for periodic checks and we wake immediately up
290 whenever the feedfile changes.)
294 .BI \-\-no-check-proportion= PERCENT
295 If the moving average of the proportion of articles being accepted
296 (rather than declined) by the peer exceeds this value, innduct uses
297 "no check mode" - ie it just sends the peer the articles with TAKETHIS
298 rather than checking first with CHECK whether the article is wanted.
299 This only affects streaming connections. The default is
303 .BI \-\-no-check-response-time= ARTICLES
304 The moving average mentioned above is an alpha-smoothed value with a
310 .BI \-\-reconnect-interval= RECONNECT-PERIOD
311 Limits initiation of new connections to one each
312 .IR RECONNECT-PERIOD .
313 This applies to reconnections if the peer has been down, and also to
314 ramping up the number of connections we are using after startup or in
315 response to an article flood. The default is
318 .BI \-\-flush-retry-interval= PERIOD
319 If our attempt to flush the feed failed (usually this will be because
320 innd is not running), try again after
325 .BI \-\-earliest-deferred-retry= PERIOD
326 When the peer responds to our offer of an article with a 431 or 436
327 NNTP response code, indicating that the article has already been
328 offered to it by another of its peers, and that we should try again,
331 before offering the article again. The default is
334 .BI \-\-backlog-rescan-interval= BACKLOG-SCAN-PERIOD
335 We scan the directory containing
337 for backlog files at least every
338 .IR BACKLOG-SCAN-PERIOD ,
339 in case the administrator has manually dropped in a file there for
344 .BI \-\-max-flush-interval= PERIOD
345 We flush the feed and start a new feedfile at least every
347 even if the current instance of the feedfile has not reached the size
352 .BI \-\-flush-finish-timeout= FLUSH-FINISH-PERIOD
354 .IR FLUSH-FINISH-PERIOD
355 ago, and are still trying to finish processing articles that were
356 written to the old feed file, we forcibly and violently make sure that
357 we can finish the old feed file: we abandon and defer all the work,
358 which includes unceremoniously dropping any connections on which
359 we've sent some of those articles but not yet had replies, as they're
360 probably stuck somehow. The default is
363 .BI \-\-idle-timeout= PERIOD
364 Connections which have had no activity for
366 will be closed. This includes connections where we have sent commands
367 or articles but have not yet had the responses, so this same value
368 doubles as the timeout after which we conclude that the peer is
369 unresponsive or the connection has become broken.
373 .BI \-\-stats-log-interval= PERIOD
374 Log statistics at least every
379 .BI \-\-low-volume-thresh= "WIN-THRESH " \-\-low-volume-window= "PERIOD "
380 If innduct has only one connection to the peer, and has processed
385 and also no articles in the last
387 it will close the connection quickly. That is, innduct switches to a
388 mode where it opens a connection for each article (or, perhaps, each
389 handful of articles arriving together).
390 The default is to close if fewer than
395 .BI \-\-max-bad-input-data-ratio= PERCENT
396 We tolerate up to this proportion of badly-formatted lines in the
397 feedfile and other input files. Every badly-formatted line is logged,
398 but if there are too many we conclude that the corruption to our
399 on-disk data is too severe, and crash; to successfully restart,
400 administrator intervention will be required. This avoids flooding the
401 logs with warnings and also arranges to abort earlyish if an attempt
402 is made to process a file in the wrong format. We need to tolerate a
403 small proportion of broken lines, if for no other reason than that a
404 crash might leave a half-blanked-out entry. The default is
408 .BI \-\-max-bad-input-data-init= LINES
409 Additionally, we tolerate this number of additional badly-formatted
410 lines, so that if the badly-formatted lines are a few but at the start
411 of the file, we don't crash immediately.
414 (which would suffice to ignore one whole corrupt 4096-byte disk block
415 filled with random data, or one corrupt 1024-byte disk block filled
416 with an inappropriate text file with a mean line length of at least
418 .SH INNDUCT VS INNFEED/NNTPSEND/INNXMIT
421 does roughly the same thing as innduct. However, the way it receives
422 information from innd can result in articles being lost (not offered
423 to peers) if innfeed crashes for any reason. This is an inherent
424 defect in the innd channel feed protocol. innduct uses a file feed,
425 constantly "tailing" the feed file, and where implemented uses
427 to reduce the latency which would come from having to constantly poll
428 the feed file. innduct is much smaller and simpler, at <5kloc to
429 innfeed's ~25kloc. innfeed needs a separate helper script or similar
430 infrastructure (of which there is an example in its manpage), whereas
431 innduct can be run directly and doesn't need help from shell scripts.
432 However, innfeed is capable of feeding multiple peers from a single
433 innfeed instance, whereas each innduct process handles exactly one
437 processes feed files in batch mode. That is, you have to periodically
438 invoke nntpsend, and when you do, the feed is flushed and articles
439 which arrived before the flush are sent to the peer. This introduces
440 a batching delay, and also means that the NNTP connection to the peer
441 needs to be remade at each batch. nntpsend (which uses innxmit)
442 cannot make use of multiple connections to a single peer site.
443 However, nntpsend automatically find which sites need feeding by
446 whereas the administrator needs to arrange to invoke innduct
447 separately for each peer.
450 is the actual NNTP feeder program used by nntpsend.
454 \fBinnfeed\fR \fBinnduct\fR \fBnntpsend/innxmit\fR
455 realtime feed Yes Yes No
457 source code size 24kloc 4.6kloc 1.9kloc
458 invoke once for all sites Yes No Yes
459 number of processes one 1/site 2/site, intermittently
464 An instance of innduct is already running for this
471 The feed has been dropped by innd, and we (or previous innducts) have
472 successfully offered all the old articles to the peer site. Our work
476 innduct was invoked with bad options or command line arguments. The
477 error message will be printed to stderr, and also (if any options or
478 arguments were passed at all) to syslog with severity
482 Things are going wrong, hopefully shortage of memory, system file
483 table entries; disk IO problems; disk full; etc. The specifics of the
484 error will be logged to syslog with severity
486 (if syslog is working!)
489 Things are going badly wrong in an unexpected way: system calls which
490 are not expected to fail are doing so, or the protocol for
491 communicating with innd is being violated, or some such. Details will
492 be logged with severity
494 (if syslog is working!)
497 These exit statuses are used by children forked by innduct to
498 communicate to the parent. You should not see them. If you do, it is
501 innduct dances a somewhat complicated dance with innd to make sure
502 that everything goes smoothly and that there are no races. (See the
503 two ascii-art diagrams in README.states for details of the protocol.) Do
504 not mess with the feedfile and other associated files, other than as
508 .IX Item "default directory"
509 Default current working directory for innduct, and also default
510 grandparent directory for the command line socket.
511 .IP \fIpathoutgoing\fR/\fIsite\fR
512 .IX Item "default feedfile"
517 Main feed file as specified in
519 This and other batchfiles used by innduct contains lines each of which
521 \& \fItoken\fR \fImessageid\fR
522 where \fItoken\fR is the inn storage API token. Such lines can be
523 written by \fBTf,Wnm\fR in a \fInewsfeeds\fR(5) entry. During
524 processing, innduct overwrites lines in the batch files which
525 correspond to articles it has processed: each such line is replaced
526 with one containing only spaces. Only innd should create
528 and only innduct should remove it.
529 .IP \fIfeedfile\fR_lock
531 Lockfile, preventing multiple innduct invocations for the same
532 feed. A process holds this lock after it has opened the lockfile,
533 made an fcntl F_SETLK call, and then checked with stat and fstat that
534 the file it now has open and has locked still has the name
535 \fIfeedfile\fR_lock. (Only) the lockholder may delete the lockfile.
536 For your convenience, after the lockfile is locked,
543 are all written to the lockfile. NB that stale lockfiles may contain
544 stale data so this information should not be relied on other than for
546 .IP \fIfeedfile\fR_flushing
547 .IX Item "flushing file"
548 Batch file: the main feedfile is renamed to this filename by innduct
549 before it asks inn to flush the feed. Only innduct should create,
550 modify or remove this file.
551 .IP \fIfeedfile\fR_defer
552 .IX Item "flushing file"
553 Batch file containing details of articles whose transmission has very
554 recently been deferred at the request of the recipient site. Created,
555 written, read and removed (only) by innduct.
556 .IP \fIfeedfile\fR_backlog.\fItime_t\fR.\fIinum\fR
557 .IX Item "backlog file"
558 Batch file containing details of articles whose transmission has less
559 recently been deferred at the request of the recipient site. Created
560 by innduct, and will also be read, updated and removed by innduct.
561 However you (the administrator) may also safely remove backlog files.
562 .IP \fIfeedfile\fR_backlog\fIsomething\fR
563 .IX Item "manual backlog file"
564 Batch file manually provided by the administrator. innduct will
565 automatically find, read and process any file matching this pattern
566 (blanking out entries for processed articles) and eventually remove
567 it. \fIsomething\fR may not contain \fB#\fR \fB~\fR or \fB/\fR.
569 Be sure to have finished writing the file before you rename it to
570 match the pattern \fIfeedfile\fR\fB_backlog\fR*, as otherwise innduct
571 may find and process the file, and even think it has finished it,
572 before you have written the complete file. You may also safely remove
574 .IP \fIpathrun\fR\fB/innduct/\fB\fIsite\fR
575 .IX Item "control command line socket"
576 Default AF_UNIX listening socket for the control command line. See
577 CONTROLLING INNDUCT, above.
578 .IP \fIfeedfile\fR_dump
579 .IX Item "debug dump file"
580 On request via a control connection innduct dumps a summary of its
581 state to this text file. This is mostly useful for debugging.
582 .IP /etc/news/inn.conf
588 and associated paths),
592 and hence effective default
596 for finding how to communicate with innd, and also for
601 Written by Ian Jackson <ijackson@chiark.greenend.org.uk>
~ian / innduct.git / blob