.SH SYNOPSIS
.B innduct
.RI [ options ]
-[
.I site
-[
-.I fqdn
-]]
+.RI [ fqdn ]
.SH DESCRIPTION
.B innduct
implements NNTP peer-to-peer news transmission including the streaming
extensions, for sending news articles to a remote site.
-One instance of innduct is run for each peer site. innduct manages
-its interaction with innd so that articles are transmitted quickly,
-and manages the retransmission its own backlog. innduct includes the
+You need to run one instance of innduct for each peer site. innduct
+manages its interaction with innd, including flushing the feed as
+appropriate, etc., so that articles are transmitted quickly, and
+manages the retransmission of its own backlog. innduct includes the
locking necessary to avoid multiple simutaneous invocations.
-By default, innduct reads the default feed file name corresponding to
+By default, innduct reads the default feedfile corresponding to
the site
.I site
-(as specified in
-.IR newsfeeds (5))
-and feeds it vian NNTP, streaming if possible, to the host
+(is
+.IR pathoutgoing / site )
+and feeds it via NNTP, streaming if possible, to the host
.IR fqdn .
If
is not specified, it defaults to
.IR site .
-Logging is sent to syslog.
-.SH OPTIONS
-.TP
-.B \-h fqdn
-Specifies the domain name of the host to connect to via NNTP. The
-default is the site name. The domain name may be specified with
-.B \-h
-or as a 2nd non-option argument, but not both.
+innduct daemonises after argument parsing, and all logging (including
+error messages) are sent to syslog (facility
+.BR news ).
+
+The best way to run innduct is probably to periodically invoke innduct
+for each feed (e.g. from cron), passing innduct it the
+.B \-q
+option to arrange that it silently exits if an innduct is already
+running for that site.
+.SH INNDUCT VS INNFEED/NNTPSEND/INNXMIT
+.TP
+.B innfeed
+does roughly the same thing as innduct. However, the way it receives
+information from innd can result in articles being lost (not offered
+to peers) if innfeed crashes for any reason. This is an inherent
+defect in the innd channel feed protocol. innduct uses a file feed,
+constantly "tailing" the feed file, and where implemented uses
+.BR inotify (2)
+to reduce the latency which would come from having to constantly poll
+the feed file. innfeed is capable of feeding multiple peers from a
+single innfeed instance, whereas each innduct process handles exactly
+one peer. innduct is much smaller and simpler, at <4kloc to innfeed's
+25kloc. innfeed needs a separate wrapper script or similar
+infrastructure (of which there is an example in its manpage), whereas
+innduct can be run directly and doesn't need help from shell scripts.
+.TP
+.B nntpsend
+processes feed files in batch mode. That is, you have to periodically
+invoke nntpsend, and when you do, the feed is flushed and articles
+which arrived before the flush are sent to the peer. This introduces
+a batching delay, and also means that the NNTP connection to the peer
+needs to be remade at each batch. nntpsend (which uses innxmit)
+cannot make use of multiple connections to a single peer site.
+However, nntpsend can be left to find automatically which sites need
+feeding by looking in
+.IR pathoutgoing .
+.TP
+.B innxmit
+is the actual NNTP feeder program used by nntpsend.
+.SH GENERAL OPTIONS
+.TP
+.BR \-f | \-\-feedfile= \fIpath\fR
+Specifies the
+.I feedfile
+to read, and indirectly specifies the paths to
+be used for various ancillary files (see FILES, below).
+If
+.I path
+ends in a
+.B /
+it is taken as a directory to use, and the actual feed file used is
+.IR path / site .
+If
+.I path
+does not start with a
+.BR / ,
+it is taken to be relative to
+.IR pathoutgoing
+from inn.conf.
+The default is
+.IR site .
+.TP
+.BR \-q | \-\-quiet-multiple
+Makes innduct silently exit (with status 0) if another innduct holds
+the lock for the site. Without \fB-q\fR, this causes a fatal error to
+be logged and a nonzero exit.
+.TP
+.BR \-\-no-daemon
+Do not daemonise. innduct runs in the foreground and all messages
+(including all debug messages) are written to stderr. A control
+command line is also available on stdin/stdout.
+.TP
+.BI \-\-no-streaming
+Do not try to use the streaming extensions to NNTP (for use eg if the
+peer can't cope when we send MODE STREAM).
+.TP
+.BI \-\-no-filemon
+Do not try to use the file change monitoring support to watch for
+writes by innd to the feed file; poll it instead. (If file monitoring
+is not compiled in, this option just downgrades the log message which
+warns about this situation.)
+.TP
+.BR \-C | \-\-inndconf= \fIFILE\fR
+Read
+.I FILE
+instead of the default
+.BR inn.conf .
+.TP
+.BI \-\-port= PORT
+Connect to port
+.I PORT
+at the remote site rather than to the NNTP port (119).
+.TP
+.BI \-\-chdir= pathrun
+Change directory to
+.IR pathrun
+at startup. The default is
+.I pathrun
+from inn.conf.
+.TP
+.BR \-\-cli= \fICLI-DIR\fR / |\fICLI-PATH\fR| none
+Listen for control command line connections on
+.IB CLI-DIR / site
+(if the value ends with a
+.BR /)
+or
+.I CLI-PATH
+(if it doesn't). See CONTROLLING INNDUCT, below.
+Note that there is a fairly short limit on the paths to AF_UNIX
+sockets. If specified as
+.IR CLI-DIR \fB/\fR,
+the directory will be created with mode 700 if necessary.
+The default is
+.B innduct/
+which means to create that directory in
+.I pathrun
+and listen on
+.RB \fIpathrun\fR /innduct/ \fIsite\fR.
+.TP
+.BI \-\-help
+Just print a brief usage message and list of the options to stdout.
+.SH TUNING OPTIONS
+You should not normally need to adjust these. Time intervals may
+specified in seconds, or as a number followed by one of the following
+units:
+.BR "s m h d" ,
+.BR "sec min hour day" ,
+.BR "das hs ks Ms" .
+.TP
+.BI \-\-max-connections= max
+Restricts the maximum number of simultaneous NNTP connections used by
+for each site to
+.IR max .
+The default is
+.BR 10 .
+There is no global limit on the number of connections.
+.TP
+.BI \-\-max-queue-per-conn= per-conn-max
+Restricts the maximum number of outstanding articles queued on any
+particular connection to
+.IR max .
+(Non-streaming connections can only handle one article at a time.)
+The default is
+.BR 200 .
+.TP
+.BI \-\-max-queue-per-file= max
+Restricts the maximum number articles read into core from any one
+input file to
+.IR max .
+The default is twice the value of per-conn-max.
+.TP
+.BI \-\-feedfile-flush-size= bytes
+Specifies that innduct should flush the feed and start a new feedfile
+when the existing feedfile size exceeds
+.IR bytes ;
+the effect is that the innduct will try to avoid the various
+batchfiles growing much beyond this size while the link to the peer is
+working. The default is
+.BR 100000 .
+.TP
+.BI \-\-period-interval= PERIOD-INTERVAL
+Specifies wakup interval and period granularity.
+innduct wakes up every
+.I PERIOD-INTERVAL
+to do various housekeeping checks. Also, many of the timeout and
+rescan intervals (those specified in this manual as
+.IR PERIOD )
+are rounded up to the next multiple of
+.IR PERIOD-INTERVAL .
+.TP
+.BI \-\-connection-timeout= TIME
+How long to allow for a connection setup attempt before giving up.
+The default is
+.BR 200s .
+.TP
+.BI \-\-stuck-flush-timeout= TIME
+How long to wait for innd to respond to a flush request before giving
+up. The default is
+.BR 100s .
+.TP
+.BI \-\-feedfile-poll= TIME
+How often to poll the feedfile for new articles written by innd
+if file monitoring
+.RI ( inotify
+or equivalent) is not available. (When file monitoring is available,
+there is no need for periodic checks and we wake immediately up
+whenever the feedfile changes.)
+The default is
+.BR 5s .
+.TP
+.BI \-\-no-check-proportion= PERCENT
+If the moving average of the proportion of articles being accepted
+(rather than declined) by the peer exceeds this value, innduct uses
+"no check mode" - ie it just sends the peer the articles with TAKETHIS
+rather than checking first with CHECK whether the article is wanted.
+This only affects streaming connections. The default is
+.B 95
+(ie, 95%).
+.TP
+.BI \-\-no-check-response-time= ARTICLES
+The moving average mentioned above is an alpha-smoothed value with a
+half-life of
+.IR ARTICLES .
+The default is
+.BR 100 .
+.TP
+.BI \-\-reconnect-interval= RECONNECT-PERIOD
+Limits initiation of new connections to one each
+.IR RECONNECT-PERIOD .
+This applies to reconnections if the peer has been down, and also to
+ramping up the number of connections we are using after startup or in
+response to an article flood. The default is
+.BR 1000s .
+.TP
+.BI \-\-flush-retry-interval= PERIOD
+If our attempt to flush the feed failed (usually this will be because
+innd is not running), try again after
+.IR PERIOD .
+The default is
+.BR 1000s .
+.TP
+.BI \-\-earliest-deferred-retry= PERIOD
+When the peer responds to our offer of an article with a 431 or 436
+NNTP response code, indicating that the article has already been
+offered to it by another of its peers, and that we should try again,
+we wait at least
+.IR PERIOD .
+before offering the article again. The default is
+.BR 50s .
+.TP
+.BI \-\-backlog-rescan-interval= BACKLOG-SCAN-PERIOD
+We scan the directory containing
+.I feedfile
+for backlog files at least every
+.IR BACKLOG-SCAN-PERIOD ,
+in case the administrator has manually dropped in a file there for
+processing.
+The default is
+.TP
+.BI \-\-max-flush-interval= PERIOD
+We flush the feed at least every
+.IR PERIOD
+even if the current instance of the feedfile has not reached the size
+threshold.
+The default is
+.BR 100000s .
+.TP
+.BI \-\-max-flush-interval= PERIOD
+We flush the feed and start a new feedfile at least every
+.IR PERIOD
+even if the current instance of the feedfile has not reached the size
+threshold.
+The default is
+.BR 100000s .
+.TP
+.BI \-\-flush-finish-timeout= FLUSH-FINISH-PERIOD
+If we flushed
+.IR FLUSH-FINISH-PERIOD
+ago, and are still trying to finish processing articles that were
+written to the old feed file, we forcibly and violently make sure that
+we do by abandoning and deferring all the work (which includes
+unceremoniously dropping any connections on which we've sent some of
+those articles but not yet had replies, as they're probably stuck
+somehow).
+The default is
+.BR 2000s .
+.TP
+.BI \-\-idle-timeout= PERIOD
+Connections which have had no activity for
+.IR PERIOD
+will be closed. This includes connections where we have sent commands
+or articles but have not yet had the responses, so this same value
+doubles as the timeout after which we conclude that the peer is
+unresponsive or the connection has become broken.
+The default is
+.BR 1000s .
+.TP
+.BI \-\-max-bad-input-data-ratio= PERCENT
+We tolerate up to this proportion of badly-formatted lines in the
+feedfile and other input files. Every badly-formatted line is logged,
+but if there are too many we conclude that the corruption to our
+on-disk data is too severe, and crash; to successfully restart,
+administrator intervention will be required. This avoids flooding the
+logs with warnings and also arranges to abort earlyish if an attempt
+is made to process a file in the wrong format.
+The default is
+.BR 1
+(ie, 1%).
+.TP
+.BI \-\-max-bad-input-data-init= LINES
+Additionally, we tolerate this number of additional badly-formatted
+lines, so that if the badly-formatted lines are a few but at the start
+of the file, we don't crash immediately.
+The default is
+.BR 30
+(which would suffice to ignore one whole corrupt 4096-byte disk block
+filled with random data, or one corrupt 1024-byte disk block filled
+with an inappropriate text file with a mean line length of at least
+35).
+.SH CONTROLLING INNDUCT
+If you tell innd to drop the feed, innduct will (when it notices,
+which will normally be the next time it decides flushes) finish up the
+articles it has in hand now, and then exit. It is harmless to cause
+innd to flush the feed (but innduct won't notice and flushing won't
+start a new feedfile; you have to leave that to innduct).
+.LP
+If you want to stop innduct you can send it SIGTERM or SIGINT, or the
+.B stop
+control command, in which case it will report statistics so far and
+quickly exit. If innduct receives SIGKILL nothing will be broken or
+corrupted; you just won't see some of the article stats.
+.LP
+innduct listens on an AF_UNIX socket, and provides a command-line
+interface which can be used to trigger various events and for
+debugging. innduct listens (by default on
+.IR pathrun \fB/innduct/\fR site )
+and when connected reads and writes lines (with unix line endings).
+The cli can most easily be accessed with a program like
+.I netcat-openbsd
+(eg
+.B nc.openbsd -U /var/run/news/innduct/
+.IR site )
+or
+.IR socat .
+The prompt is
+.IR site \fB|\fR.
+.LP
+The following control commands are supported:
+.TP
+.B h
+Print a list of all the commands understood. This list includes
+undocumented commands which mess with innduct's internal state and
+should only be used by a developer in conjuction with the innduct
+source code.
+.TP
+.B flush
+Start a new feed file and trigger a flush of the feed. (Or, cause
+the
+.I FLUSH-FINISH-PERIOD
+to expire early, forcibly completing a previously started flush.)
+.TP
+.B stop
+Log statistics and exit. (Same effect as SIGTERM or SIGINT.)
+.TP
+.BR "dump q" | a
+Writes information about innduct's state to a plain text file
+.IR feedfile \fB_dump\fR.
+This overwrites any previous dump.
+.B "dump q"
+is a summary including general state and a list of connections;
+.B "dump a"
+also includes information about each article innduct is dealing with.
+.TP
+.B next blscan
+Requests that innduct rescan for new backlog files at the next
+.I PERIOD
+poll. Normally innduct assumes that any backlog files dropped in by
+the administrator are not urgent and may not get around to noticing
+them for
+.IR BACKLOG-SCAN-PERIOD .
+.TP
+.B next conn
+Resets the connection startup delay counter so that innduct may
+consider making a new connection to the peer right away, regardless
+of the setting of
+.IR RECONNECT-PERIOD .
+A connection attempt will still only be made if innduct feels that it
+needs one, and innduct may wait up to
+.I PERIOD
+before actually starting the attempt.
+.IR BACKLOG-SCAN-PERIOD .
+.SH EXIT STATUS
+.TP
+.B 0
+An instance of innduct is already running for this
+.I feedfile
+and
+.B -q
+was specified.
+.TP
+.B 4
+The feed has been dropped by innd, and we (or previous innducts) have
+successfully offered all the old articles to the peer site. Our work
+is done.
+.TP
+.B 8
+innduct was invoked with bad options or command line arguments. The
+error message will be printed to stderr, and also (if any options or
+arguments were passed at all) to syslog with severity
+.BR crit .
+.TP
+.B 12
+Things are going wrong, hopefully shortage of memory, system file
+table entries; disk IO problems; disk full; etc. The specifics of the
+error will be logged to syslog with severity
+.B err
+(if syslog is working!)
+.TP
+.B 16
+Things are going badly wrong in an unexpected way: system calls which
+are not expected to fail are doing so, or the protocol for
+communicating with innd is being violated, or some such. Details will
+be logged with severity
+.B crit
+(if syslog is working!)
+.TP
+.BR 24 - 27
+These exit statuses are used by children forked by innduct to
+communicate to the parent. You should not see them. If you do, it is
+a bug.
.SH FILES
+innduct dances a somewhat complicated dance with innd to make sure
+that everything goes smoothly and that there are no races. (See the
+two ascii-art diagrams in innduct.c for details of the protocol.) Do
+not mess with the feedfile and other associated files, other than as
+explained here:
.IX Header "FILES"
+.IP \fIpathrun\fR
+.IX Item "default directory"
+Default current working directory for innduct, and also default
+parent directory for the command line socket.
.IP \fIpathoutgoing\fR/\fIsite\fR
.IX Item "default feedfile"
Default
made an fcntl F_SETLK call, and then checked with stat and fstat that
the file it now has open and has locked still has the name
\fIfeedfile\fR_lock. (Only) the lockholder may delete the lockfile.
+For your convenience, after the lockfile is locked,
+.IR innfeed 's
+pid, the
+.IR site ,
+.IR feedfile
+and
+.IR fqdn
+are all written to the lockfile. NB that stale lockfiles may contain
+stale data so this information should not be relied on other than for
+troubleshooting.
.IP \fIfeedfile\fR_flushing
.IX Item "flushing file"
Batch file: the main feedfile is renamed to this filename by innduct
Batch file containing details of articles whose transmission has
recently been deferred at the request of the recipient site. Created,
written, read and removed by innduct.
-.IP \fIfeedfile\fR_defer
-.IX Item "defer file"
-Batch file containing details of articles whose transmission has
-recently been deferred at the request of the recipient site. Created,
-written, read and removed by innduct.
.IP \fIfeedfile\fR_backlog.\fItime_t\fR.\fIinum\fR
.IX Item "backlog file"
Batch file containing details of articles whose transmission has less
recently been deferred at the request of the recipient site. Created
-by innduct, and will also be read and removed by innduct. However the
-administrator may also safely remove backlog files.
+by innduct, and will also be read and removed by innduct. However you
+(the administrator) may also safely remove backlog files.
.IP \fIfeedfile\fR_backlog\fIsomething\fR
.IX Item "manual backlog file"
Batch file manually provided by the administrator. The file should be
complete and ready to process at the time it is renamed or hardlinked
to this name. innduct will then automatically find and read and
process it and eventually remove it. The administrator may also
-safely remove backlog files. \fIsomething\fR should not contain
-\fB#\fR or \fB~\fR.
+safely remove backlog files. \fIsomething\fR may not contain \fB#\fR
+\fB~\fR or \fB/\fR. Be sure to have finished writing the file before
+you rename it to match the pattern \fIfeedfile\fR\fB_backlog\fR*, as
+otherwise innduct may find and process the file and read it to EOF
+before you have finished creating it.
+.IP \fIpathrun\fR\fB/innduct/\fB\fIsite\fR
+.IX Item "control command line socket"
+Default AF_UNIX listening socket for the control command line. See
+CONTROLLING INNDUCT, above.
+.IP \fIfeedfile\fR_dump
+.IX Item "debug dump file"
+On request via a control connection innduct dumps a summary of its
+state to this text file. This is mostly useful for debugging.
+.IP /etc/news/inn.conf
+.IX Item inn.conf
+Used for
+.IR pathoutgoing
+(to compute default
+.IR feedfile
+and associated paths),
+.IR pathrun
+(to compute default
+.IR CLI-DIR
+and
+.IR CLI-PATH ),
+for finding how to communicate with innd, and also for
+.IR sourceaddress
+and/or
+.IR sourceaddress6 .
.SH HISTORY
Written by Ian Jackson <ijackson@chiark.greenend.org.uk>
.SH "SEE ALSO"
~ian / inn-innduct.git / blobdiff