


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 proces-
       sor 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 cur-
       rent  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 direc-
       tories  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  cur-
       rent 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 success-
       fully, @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



                                                                1





svlogd(8)                                               svlogd(8)


       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 pro-
              cessed.

       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.




                                                                2





svlogd(8)                                               svlogd(8)


       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  pack-
              ages still go to the log directory.

       pprefix
              tells svlogd to prefix each line to be written to the log direc-
              tory, 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.  Dese-
       lected 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



                                                                3





svlogd(8)                                               svlogd(8)


       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 charac-
              ters of a log message only.  Default is 1000.

       -b buflen
              buffer size.  Set the size of the buffer svlogd uses when  read-
              ing  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/



                                                                4





svlogd(8)                                               svlogd(8)


AUTHOR
       Gerrit Pape <pape@smarden.org>























































                                                                5


