svlogd(8)                                                     System Manager's Manual                                                    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 automati-
       cally 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  neces-
       sary 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, this must be done manually, e.g. for keeping 10 log files:

        ls -1 @* |sort |sed -ne '10,$p' |xargs rm

   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 can-
              not 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 time-
              out 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 send-
              ing 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 des-
       elected 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 stan-
              dard 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 writ-
              ing 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 writ-
              ing 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.  For svlogd instances that process a lot of data in short time, the buffer  size  should  be
              increased to improve performance.

       -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)