logapp - An application output supervisor.
logapp
[option]... application
[--logapp_option]... [app.-argument]...
applicationsymlink
[--logapp_option]... [application-argument]...
Instead of calling logapp directly you can also create a symlink
with the name of the application pointing to logapp. Logapp will
automatically start the application the name points to. It will also work if
the symlink name is prefixed with log.
Logapp is a wrapper utility that helps supervise the execution of
applications that produce heavy console output (e.g. make, CVS and
Subversion). It does this by logging, trimming, and coloring each line of
the output before displaying it. It can be called instead of the executable
that should be monitored; it then starts the application and logs all of its
console output to a file. The output shown in the terminal is preprocessed,
e.g. to limit the length of printed lines and to show the stderr output in a
different color. It is also possible to automatically highlight lines that
match a certain regular expression. The output is therefore reduced to the
necessary amount, and all important lines are easy to identify.
The options provided before the application argument are
processed directly by logapp. Options provided after the application
argument are only parsed if they are prefixed with --logapp_ (long
option names only) otherwise they are passed to the application. If logapp
is called via a symlink all unprefixed options are passed to the
application.
Every application usually uses two independent output streams:
stdout for normal output and stderr for errors and important
messages. Both of them are handled independently by logapp, therefore many
options are available for both streams.
Bool options are accepting 1/0 and true/false as
value. For long boolean options the value can be omitted, in that case it
will be assumed to be 'true'.
- -?, --help
- Show a short overview over all available options.
- --version
- Show version information.
- --configfile=FILE
- Use a specific configuration file instead of searching the configuration
search paths.
- --showconfig
- Print the current configuration of logapp and exit before the application
is executed. This can be used this to check if all configuration options
are setup correctly if something doesn't work as expected.
- --configsection=NAME
- Enable a specific section in the configuration file. If this option is not
provided the application name is used as default.
- --disable
- This disables logapp data handling completely. The application is still
started, but logapp won't touch the data streams coming from the
application. Neither logging nor output formating is performed, only the
execution time and the exit state tracked. This is useful if logapp won't
be able to deal with expected data correctly, for example when starting
curses based applications. Have a look at --disable_keywords to see
how this option can be enabled automatically.
- --disable_keywords=keywordlist
- With this option a list of comma separated keywords can be provided which
will cause the --disable to be enabled automatically if found in
the applications option list. This is useful if an application usually
provides line-based output, but creates binary data or uses a curses based
frontend if called with a specific parameter. You can also use the
--detectescape option for another way to do this without disabling
the logging functionality.
- --detectescape=bool
- This option can be used to switch escape-sequence detection on or off.
With escape-sequence detection logapp will automatically enable char-based
stream handling as soon as an escape-sequence is part of the specific
stream. This behavior can be useful if you are working with an application
that is usually line-based, but starts other applications which may be
using escape sequences to format the screen. This option will prevent the
terminal from being messed up in that case.
- --dumbterm=bool
- With this option set to true there will be no terminal output coloring for
stdout and stderr. Normally this option is disabled and
logapp tries to detect "dumb" terminals itself.
- --usepty=bool
- This option is only available if logapp has been compiled with PTY
support. If PTY support is enabled with this option set to true, logapp
will open a pseudo terminal for stdout. This helps wenn
running logapp with applications that usually need a real terminal for
output. You can disable this option for most line based applications like
make, CVS or Subversion. Other applications like telnet or picocom may
produce strange results when used without PTY support.
- --ptyremovecr=bool
- This option is only available if logapp has been compiled with PTY
support. When using a pseudo terminal for getting the application output
you will always get CR-LF line endings, which is usually not desired when
working in UNIX environments. With this option enabled, logapp will
automatically translate all CR-LF line endings in LF line endings. This
option is enabled as default.
- --stdout_blen=bytes
- --stderr_blen=bytes
- The line buffer size can be adjusted for stdout and stderr
independently with this option. If the value is too small, lines will be
split up if the buffer is full. The default is 2048 byte which
should be big enough for most applications.
- --stdout_charbased=bool
- --stderr_charbased=bool
- If you want to use logapp with applications that do not produce line based
output you can enable this options for stdout and stderr
independently. With this option enabled logapp won't expect complete lines
and will handle data as it comes in. By default all single data packets
are written to a new line if this option is enabled, this can be changed
with the --alignlog option. If the result will be usable depends on
what kind of data is generated by the application.
- --extended-regexp=bool
- If this option is enabled logapp will interpret provided regular
expression patterns as extended regular expressions. The default is to use
basic regular expressions.
This section contains options that affect the logfile.
- -l,
--logfile=file
- This option can be used to change the file that is used for storing the
logged application data. If an empty string is provided, logging is
disabled and no logfile will be created. The default is that logapp
creates a logfile called logapp.log in the current directory.
- -a,
--appendlog=bool
- This option specifies if the logfile will be truncated or if the data will
be appended to an existing file on logapp startup.
- --maxlogsize=kibyte
- To limit the maximum size of the logfile you can set this option to a
value between 10 and 4000000 kiBytes. The default is 0 which
disables the logfile size limit. There are different ways implemented how
the logfile is limited. Have a look at the options --logrename and
--circularlog to learn more. The default way is that the extension
.old is added to the logfile and a new logfile is started.
- --logrename=bool
- This option specifies the behavior when a logfile is to be truncated. If
--logrename is enabled the logfile is renamed. The new filename
will be the same as before with the extension defined with
--oldlogext added. The default extension is .old. This option is
used together with the value of --appendlog and
--maxlogsize
- --circularlog=bool
- If this option is enabled together with a logfile size limit set with
--maxlogsize, the logfile will be used in a circular way. This
means if the maximum size is reached, the file pointer is set to the
beginning of the file and the old content is overwritten from the
beginning. There are tags added to the logfile to help navigating in the
file.
- --oldlogext=extension
- This defines the extion that is used when logapp is renaming a logfile.
The --logrename option defines if logapp will rename the file and
the default extension is .old.
- --locklogfile=bool
- With this option active the logfile is locked in order to prevent it to be
overwritten by another task. This is useful if otherwise an unreadable mix
up of different contents would be the result. Depending on the value of
the --maxaltlogfiles option another logfile is chosen with the same
name and a number added. Logfile locking is activated by default.
- --warnlogfilelock=bool
- This options defines if there should be a warning printed to the console
if the chosen logfile is already locked or in other means not accessible.
In this case there will be a message before the application is started and
directly after its execution where the name of the alternative logfile is
mentioned. This option is enabled by default. Also have a look at the
--printlogname where you can define to always get the current
logfile reported.
- --printlogname=bool
- This option defines if the name of the used logfile should be printed
after the application has finished its execution. This option is disabled
by default. Also have a look at the --warnlogfilelock where you can
enable/disable a warning if the logfile name is changed because of a
locked logfile.
- --maxaltlogfiles=number
- This options defines the maximum number that can be added to the logfile
name, if the original file is not accessible. On logapp startup it will be
checked if the currently defined logfile is writeable, if this is not the
case automatically a number is added to the filename. If the alternative
file is also not accessible this number is increased until a file is
writable or the value of maxaltlogfiles is reached. In the latter
case the application will exit with an error. If a value of 0 is used only
the original logfile name is tried. Also have a look at the
--warnlogfilelock and --printlogname options to define if
there should be messages about the currently used logfile.
- --alignlog=bool
- This option is used together with --stdout_charbased and
--stderr_charbased and defines if data packets are written to the
logfile as they come or if they are each written to a new line. The
default is that each data packet is written to a new line, set this option
to false to disable it.
- --alignlinebreaks=bool
- This option is used together with --stdout_charbased and
--stderr_charbased and aligns the lines to the left in the logfile
with regard to prefix and timestamp. This option is enabled by
default.
- --jointimeout=time
- This option is used together with --stdout_charbased and
--stderr_charbased and defines a ms timeout for joining single
packets to one. This means if for example two chars get written within the
timeout, they are treated as one packet. This is best used together with
--alignlog and --logtime. Use this option if the data
packets have lost their coherency for some reason (e.g. if the data comes
through a serial line). This feature is disabled by default and can be
enabled by setting time to a value bigger than 0 ms.
- -t,
--logtime=bool
- This option can be enabled to add a ms timestamp to each line of the
logfile. Normally the time since the application start is used, but this
can be changed with the --logreltime option.
- --logreltime=bool
- If this option is set this to true, the --logreltime option will
use the relative time since the last line for the logged timestamps.
- --logenv=bool
- With this option set to true logapp will add a list of all active
environment variables to the logfile. This option is disabled by
default.
- -p,
--stdout_lineprefix=prefix
- -P,
--stderr_lineprefix=prefix
- To be able to distinguish stdout and stderr output in the
logfile logapp can prefix each line with a string that indicates if the
line belongs to a specific data stream. Those strings can be changed with
this option. The default is that stdout does not have a prefix and
stderr is prefixed with STDERR:.
This section contains options that affect the visual output on the
console.
- --dumbterm=bool
- This option disables output coloring. This is usually done automatically
if a dumb terminal is detected.
- -s,
--print_summary=bool
- If this option is set to true, then a short summary will be printed after
the application has terminated. This option is disabled by default.
- -f,
--stdout_fgcol=color
- -F,
--stderr_fgcol=color
- This options define the foreground color for the specific data stream. The
value can be one of the entries in the console color table at the
end of this section.
- -b,
--stdout_bold=bool
- -B,
--stderr_bold=bool
- This options define if the font for the specific data stream should be
printed bold.
- -r,
--stdout_regexp=regular expression
- -R,
--stderr_regexp=regular expression
- The regular expression that can be defined with this option is applied to
every line of the specific data stream. On a match the background color
changes to the value provided with the --stdout_regexp_bgcol
respectively --stderr_regexp_bgcol option.
- --stdout_regexp_bgcol=color
- --stderr_regexp_bgcol=color
- This options define the background color for the specific data stream for
the case that the appropriate regular expression provided with
--stdout_regexp or --stderr_regexp matches. The value can be
one of the entries in the console color table at the end of this
section.
- -c,
--stdout_clip=width
- -C,
--stderr_clip=width
- This options define at which column the output should be clipped for the
specific stream to reduce the amount of data written to the console. If a
value of -1 is provided clipping is disabled for the stream. A
value of -2 sets the clipping to the current console width. It is
also possible to use disable and auto instead of the numeric
values. The default is that stdout is limited to the console width
and that clipping is deactivated for stderr.
Console color table
# |
color |
-1 |
(console) default |
0 |
black |
1 |
red |
2 |
green |
3 |
brown |
4 |
blue |
5 |
magenta |
6 |
cyan |
7 |
white |
This section contains options that configure the execution of
commands on regular expression matches.
- --exitonexecfail=BOOL
- This option defines if logapp should exit and end the wrapped application
if the return value of an executed command indicates a failure. As default
this option is disabled and logapp ignores the return state of executed
commands.
- --preexec=command
- The command that can be provided with this option is executed directly
before the application is started. At this time the header is already
written to the logfile and can be parsed by the command.
- --postexec=command
- The command that can be provided with this option is executed directly
after the application has exited. At this time the logfile is already
closed for writing so all application output and the footer are already
included and can be processed by the command.
- -e,
--stdout_execregexp=regular expression
- -E,
--stderr_execregexp=regular expression
- The regular expression that can be defined with this option is applied to
every line of the specific data stream. On a match the command provided
with the --stdout_execcommand respectively
--stderr_execcomand option is executed. An empty value for this
option disables the regular expression matching.
- -x,
--stdout_execcommand=command
- -X,
--stderr_execcommand=command
- This option defines the command that is executed on a regular expression
match. The regular expression can be defined separately for the
stdout and stderr stream with the --stdout_execregexp
respectively --stderr_execregexp option.
Regular expressions are patterns that describe strings. Logapp
uses this patterns to execute actions based on strings found in the data
stream. The implementation is identical to the one that is used by
grep.
Logapp understands the "basic" and "extended"
syntax of regular expressions as defined by POSIX. The default is to use the
basic set, but you can switch to extended patterns with the
--extended-regexp parameter. Please have a look at the grep(1)
and regex(7) manpage for detailed information.
- String
- Matches "String"
- ^String
- Matches "String" at the beginning of a line
- String$
- Matches "String" at the end of a line
- ^String$
- Line contains only "String"
- [Ss]tring
- Matches "String" or "string"
- Str.ng
- The dot matches all characters, so this matches for example
"String" or "Strong"
- Str.*ng
- The dot together with star matches any number of characters, so this
matches for example "String" or "Streaming"
- ^[A-Z] *
- Matches any one of the characters from A to Z at the beginning of a line
followed by zero or any number of spaces
- String\|Word
- Matches "String" or "Word" when working with basic
regular expressions
- String|Word
- Matches "String" or "Word" when working with
extended regular expressions
- TERM
- This variable is checked to see which type of console logapp is running
in. Currently only the value dumb is handled in a special way
— by disabling console colors. If the TERM variable is
missing also a dumb terminal is assumed. The setting can be overridden by
enabling/disabling the dumb terminal mode using the --dumbterm
option.
- ~/.logapprc, /etc/logapp.conf,
/etc/logapp/logapp.conf
- Configuration file locations that are tried if no --configfile
option is provided.
See the TODO file included in the source package.
Copyright (C) 2007–2011 Michael Brunner
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the General Public
License for more details.