svlogd(8)                                                            svlogd(8)



NAME
       svlogd - runit's service logging daemon

SYNOPSIS
       svlogd [-tttv] [-r c] [-R xyz] [-l len] [-b buflen] logs

DESCRIPTION
       logs consists of one or more arguments, each specifying a directory.

       svlogd continuously reads log data from its standard input, optionally
       filters log messages, and writes the data to one or more automatically
       rotated logs.

       Recent log files can automatically be processed by an arbitrary
       processor program when they are rotated, and svlogd can be told to
       alert selected log messages to standard error, and through udp.

       svlogd runs until it sees end-of-file on standard input or is sent a
       TERM signal, see below.

   LOG DIRECTORY
       A log directory log contains some number of old log files, and the
       current log file current.  Old log files have a file name starting with
       @ followed by a precise timestamp (see the daemontools' tai64n
       program), indicating when current was rotated and renamed to this file.

       A log directory additionally contains the lock file lock, maybe state
       and newstate, and optionally the file config.  svlogd creates necessary
       files if they don't exist.

       If svlogd has trouble opening a log directory, it prints a warning, and
       ignores this log directory.  If svlogd is unable to open all log
       directories given at the command line, it exits with an error.  This
       can happen on start-up or after receiving a HUP signal.

   LOG FILE ROTATION
       svlogd appends selected log messages to the current log file.  If
       current has size bytes or more (or there is a new-line within the last
       len of size bytes), or is older than a specified amount of time,
       current is rotated:

       svlogd closes current, changes permission of current to 0755, renames
       current to @timestamp.s, and starts with a new empty current.  If
       svlogd sees num or more old log files in the log directory, it removes
       the oldest one.  Note that this doesn't decrease the number of log
       files if there are already more than num log files.

   PROCESSOR
       If svlogd is told to process recent log files, it saves current to
       @timestamp.u, feeds @timestamp.u through ``sh -c "processor"'' and
       writes the output to @timestamp.t.  If the processor finishes
       successfully, @timestamp.t is renamed to @timestamp.s, and @timestamp.u
       is deleted; otherwise @timestamp.t is deleted and the processor is
       started again.  svlogd also saves any output that the processor writes
       to file descriptor 5, and makes that output available on file
       descriptor 4 when running processor on the next log file rotation.

       A processor is run in the background.  If svlogd sees a previously
       started processor still running when trying to start a new one for the
       same log, it blocks until the currently running processor has finished
       successfully.  Only the HUP signal works in that situation.  Note that
       this may block any program feeding its log data to svlogd.


   CONFIG
       On startup, and after receiving a HUP signal, svlogd checks for each
       log directory log if the configuration file log/config exists, and if
       so, reads the file line by line and adjusts configuration for log as
       follows:

       If the line is empty, or starts with a ``#'', it is ignored.  A line of
       the form

       ssize  sets the maximum file size of current when svlogd should rotate
              the current log file to size bytes.  Default is 1000000.  If
              size is zero, svlogd doesn't rotate log files.  You should set
              size to at least (2 * len).

       nnum   sets the number of old log files svlogd should maintain to num.
              If svlogd sees more that num old log files in log after log file
              rotation, it deletes the oldest one.  Default is 10.  If num is
              zero, svlogd doesn't remove old log files.

       Nmin   sets the minimum number of old log files svlogd should maintain
              to min.  min must be less than num.  If min is set, and svlogd
              cannot write to current because the filesystem is full, and it
              sees more than min old log files, it deletes the oldest one.

       ttimeout
              sets the maximum age of the current log file when svlogd should
              rotate the current log file to timeout seconds.  If current is
              timeout seconds old, and is not empty, svlogd forces log file
              rotation.

       !processor
              tells svlogd to feed each recent log file through processor (see
              above) on log file rotation.  By default log files are not
              processed.

       ua.b.c.d[:port]
              tells svlogd to transmit the first len characters of selected
              log messages to the IP address a.b.c.d, port number port.  If
              port isn't set, the default port for syslog is used (514).  len
              can be set through the -l option, see below.  If svlogd has
              trouble sending udp packets, it writes error messages to the log
              directory.  Attention: logging through udp is unreliable, and
              should be used in private networks only.

       Ua.b.c.d[:port]
              is the same as the u line above, but the log messages are no
              longer written to the log directory, but transmitted through udp
              only.  Error messages from svlogd concerning sending udp
              packages still go to the log directory.

       pprefix
              tells svlogd to prefix each line to be written to the log
              directory, to standard error, or through UDP, with prefix.

       If a line starts with a -, +, e, or E, svlogd matches the first len
       characters of each log message against pattern and acts accordingly:

       -pattern
              the log message is deselected.

       +pattern
              the log message is selected.

       epattern
              the log message is selected to be printed to standard error.

       Epattern
              the log message is deselected to be printed to standard error.

       Initially each line is selected to be written to log/current.
       Deselected log messages are discarded from log.  Initially each line is
       deselected to be written to standard err.  Log messages selected for
       standard error are written to standard error.

PATTERN MATCHING
       svlogd matches a log message against the string pattern as follows:

       pattern is applied to the log message one character by one, starting
       with the first.  A character not a star (``*'') and not a plus (``+'')
       matches itself.  A plus matches the next character in pattern in the
       log message one or more times.  A star before the end of pattern
       matches any string in the log message that does not include the next
       character in pattern.  A star at the end of pattern matches any string.

       Timestamps optionally added by svlogd are not considered part of the
       log message.

       An svlogd pattern is not a regular expression.  For example consider a
       log message like this

        2005-12-18_09:13:50.97618 tcpsvd: info: pid 1977 from 10.4.1.14

       The following pattern doesn't match

        -*pid*

       because the first star matches up to the first p in tcpsvd, and then
       the match fails because i is not s.  To match this log message, you can
       use a pattern like this instead

        -*: *: pid *

OPTIONS
       -t     timestamp.  Prefix each selected line with a precise timestamp
              (see the daemontools' tai64n program) when writing to log or to
              standard error.

       -tt    timestamp.  Prefix each selected line with a human readable,
              sortable UTC timestamp of the form YYYY-MM-DD_HH:MM:SS.xxxxx
              when writing to log or to standard error.

       -ttt   timestamp.  Prefix each selected line with a human readable,
              sortable UTC timestamp of the form YYYY-MM-DDTHH:MM:SS.xxxxx
              when writing to log or to standard error.

       -r c   replace.  c must be a single character.  Replace non-printable
              characters in log messages with c.  Characters are replaced
              before pattern matching is applied.

       -R xyz replace charset.  Additionally to non-printable characters,
              replace all characters found in xyz with c (default ``_'').

       -l len line length.  Pattern matching applies to the first len
              characters of a log message only.  Default is 1000.

       -b buflen
              buffer size.  Set the size of the buffer svlogd uses when
              reading from standard input and writing to logs to buflen.
              Default is 1024.  buflen must be greater than len.

       -v     verbose.  Print verbose messages to standard error.

SIGNALS
       If svlogd is sent a HUP signal, it closes and reopens all logs, and
       updates their configuration according to log/config.  If svlogd has
       trouble opening a log directory, it prints a warning, and discards this
       log directory.  If svlogd is unable to open all log directories given
       at the command line, it exits with an error.

       If svlogd is sent a TERM signal, or if it sees end-of-file on standard
       input, it stops reading standard input, processes the data in the
       buffer, waits for all processor subprocesses to finish if any, and
       exits 0 as soon as possible.

       If svlogd is sent an ALRM signal, it forces log file rotation for all
       logs with a non empty current log file.

SEE ALSO
       sv(8), runsv(8), chpst(8), runit(8), runit-init(8), runsvdir(8),
       runsvchdir(8)

       http://smarden.org/runit/

AUTHOR
       Gerrit Pape <pape@smarden.org>



                                                                     svlogd(8)
