YAZ-LOG(7) Conventions and miscellaneous YAZ-LOG(7)NAMEyaz-log - Log handling in all yaz-based programs
SYNOPSIS
yaz-XXXX [-v loglevel,...] [-l logfile]
DESCRIPTION
All YAZ-based programs use a common log subsystem, and should support
common command line options for controlling it. This man page documents
those.
OPTIONS-l logfile
Specify the file where the log is to be written. If none is
specified, stderr is used. The log is appended to this file. If the
file grows overly large, it is silently rotated: It is renamed to
logfile.1, logfile.2, .., 9 (old such file is deleted), and a new
file is opened. The limit defaults to 1GB, but can be set by the
program. The rotating limit can be specified with option -r for the
YAZ frontend server (yaz-ztest).
Rotation can also be implicitly enabled by using a filename which
gets changed for a given date, due to substitutions as given by the
strftime(3) function.
-v loglevel
Specify the logging level. The argument is a set of log level
names, separated by commas (no whitespace!), optionally preceded by
a '-' to negate that level. Most programs have their own default,
often containing fatal,warn,log, and some application-specific
values. The default list can be cleared with the word none, or
individual bits can be removed by prefixing them with a dash '-'.
LOG LEVELS TO CONTROL LOGGING
Some of the log levels control the way the log is written.
flush causes the log to be flushed after every write. This can have
serious implications to performance, and should not be used in
production. On the other hand, when debugging a program crash, this can
be extremely useful. The option debug implies flush as well.
notime prevents the writing of time stamps. This is intended for
automatic test scripts, which should produce predictable log files that
are easy to compare.
GENERAL LOG LEVELS IN YAZ ITSELF
YAZ itself uses the following log levels:
fatal for fatal errors, that prevent further execution of the program.
warn for warnings about things that should be corrected.
debug for debugging. This flag may be used temporarily when developing
or debugging yaz, or a program that uses yaz. It is practically
deprecated, you should be defining and using your own log levels (see
below).
all turns on almost all hard-coded log levels.
loglevel logs information about the log levels used by the program.
Every time the log level is changed, lists all bits that are on. Every
time a module asks for its log bits, this is logged. This can be used
for getting an idea of what log levels are available in any program
that uses yaz-log. Start the program with -v none,loglevel, and do some
common operations with it. Another way is to grep for
yaz_log_module_level in the source code, as in
find . -name '*.[ch]' -print |
xargs grep yaz_log_module_level |
grep '"' |
cut -d'"' -f2 |
sort -u
eventl, malloc, nmem, odr are used internally for debugging yaz.
LOG LEVELS FOR CLIENTS
zoom logs the calls to the zoom API, which may be useful in debugging
client applications.
LOG LEVELS FOR SERVERS
server logs the server functions on a high level, starting up,
listening on a port, etc.
session logs individual sessions (connections).
request logs a one-liner for each request (init, search, etc.).
requestdetail logs the details of every request, before it is passed to
the back-end, and the results received from it.
Each server program (zebra, etc.) is supposed to define its own log
levels in addition to these. As they depend on the server in question,
they can not be described here. See above how to find out about them.
LOGGING EXAMPLES
See what log levels yaz-ztest is using:
yaz-ztest -1 -v none,loglevel
14:43:29-23/11 [loglevel] Setting log level to 4096 = 0x00001000
14:43:29-23/11 [loglevel] Static log bit 00000001 'fatal' is off
14:43:29-23/11 [loglevel] Static log bit 00000002 'debug' is off
14:43:29-23/11 [loglevel] Static log bit 00000004 'warn' is off
14:43:29-23/11 [loglevel] Static log bit 00000008 'log' is off
14:43:29-23/11 [loglevel] Static log bit 00000080 'malloc' is off
14:43:29-23/11 [loglevel] Static log bit 00000800 'flush' is off
14:43:29-23/11 [loglevel] Static log bit 00001000 'loglevel' is ON
14:43:29-23/11 [loglevel] Static log bit 00002000 'server' is off
14:43:29-23/11 [loglevel] Dynamic log bit 00004000 'session' is off
14:43:29-23/11 [loglevel] Dynamic log bit 00008000 'request' is off
14:44:13-23/11 yaz-ztest [loglevel] returning log bit 0x4000 for 'session'
14:44:13-23/11 yaz-ztest [loglevel] returning log bit 0x2000 for 'server'
14:44:13-23/11 yaz-ztest [loglevel] returning NO log bit for 'eventl'
14:44:20-23/11 yaz-ztest [loglevel] returning log bit 0x4000 for 'session'
14:44:20-23/11 yaz-ztest [loglevel] returning log bit 0x8000 for 'request'
14:44:20-23/11 yaz-ztest [loglevel] returning NO log bit for 'requestdetail'
14:44:20-23/11 yaz-ztest [loglevel] returning NO log bit for 'odr'
14:44:20-23/11 yaz-ztest [loglevel] returning NO log bit for 'ztest'
See the details of the requests for yaz-ztest
./yaz-ztest -1 -v requestdetail
14:45:35-23/11 yaz-ztest [server] Adding static Z3950 listener on tcp:@:9999
14:45:35-23/11 yaz-ztest [server] Starting server ./yaz-ztest pid=32200
14:45:38-23/11 yaz-ztest [session] Starting session from tcp:127.0.0.1 (pid=32200)
14:45:38-23/11 yaz-ztest [requestdetail] Got initRequest
14:45:38-23/11 yaz-ztest [requestdetail] Id: 81
14:45:38-23/11 yaz-ztest [requestdetail] Name: YAZ
14:45:38-23/11 yaz-ztest [requestdetail] Version: 2.0.28
14:45:38-23/11 yaz-ztest [requestdetail] Negotiated to v3: srch prst del extendedServices namedresults scan sort
14:45:38-23/11 yaz-ztest [request] Init from 'YAZ' (81) (ver 2.0.28) OK
14:45:39-23/11 yaz-ztest [requestdetail] Got SearchRequest.
14:45:39-23/11 yaz-ztest [requestdetail] ResultSet '1'
14:45:39-23/11 yaz-ztest [requestdetail] Database 'Default'
14:45:39-23/11 yaz-ztest [requestdetail] RPN query. Type: Bib-1
14:45:39-23/11 yaz-ztest [requestdetail] term 'foo' (general)
14:45:39-23/11 yaz-ztest [requestdetail] resultCount: 7
14:45:39-23/11 yaz-ztest [request] Search Z: @attrset Bib-1 foo OK:7 hits
14:45:41-23/11 yaz-ztest [requestdetail] Got PresentRequest.
14:45:41-23/11 yaz-ztest [requestdetail] Request to pack 1+1 1
14:45:41-23/11 yaz-ztest [requestdetail] pms=1048576, mrs=1048576
14:45:41-23/11 yaz-ztest [request] Present: [1] 1+1 OK 1 records returned
LOG FILENAME EXAMPLES
A file with format my_YYYYMMDD.log (where Y, M, D is year, month, and
day digits) is given as follows: -l my_%Y%m%d.log . And since the
filename is depending on day, rotation will occur on midnight.
A weekly log could be specified as -l my_%Y%U.log.
FILES
prefix/include/yaz/log.hprefix/src/log.c
SEE ALSOyaz(7)yaz-ztest(8)yaz-client(1)strftime(3)YAZ 5.15.1 11/12/2015 YAZ-LOG(7)
