https://github.com/cevich/ringwrap
This program allows a wrapper command to be asynchronously enabled and disabled around another command
https://github.com/cevich/ringwrap
Last synced: 11 months ago
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This program allows a wrapper command to be asynchronously enabled and disabled around another command
- Host: GitHub
- URL: https://github.com/cevich/ringwrap
- Owner: cevich
- License: lgpl-2.1
- Created: 2016-09-12T20:26:50.000Z (almost 10 years ago)
- Default Branch: master
- Last Pushed: 2016-09-12T20:27:50.000Z (almost 10 years ago)
- Last Synced: 2025-03-20T11:21:28.687Z (about 1 year ago)
- Language: C
- Size: 28.3 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README
- License: LICENSE_LGPL
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README
#
# Copyright (C) 2010 by Chris Evich
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library 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 GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
/**************************************************
********************* QUICK DEMO ******************
**************************************************/
./ringwrap "df -h > /dev/null" --init
./ringwrap "df -h > /dev/null" --begin
./ringwrap "df -h > /dev/null" # repeat as many times as you like
./ringwrap "df -h > /dev/null" --end
# examine /tmp/ringwrap-strace/ contains only last 10 runs
./ringwrap "df -h > /dev/null" --fini
/**************************************************
********************* COMPLEX DEMO ****************
**************************************************/
./ringwrap -w "strace -o @@@" -k 10 -o /tmp/diskprob "df -h > /dev/null" -i
./ringwrap "df -h > /dev/null" -b
./ringwrap "df -h > /dev/null" # repeat as many times as you like
./ringwrap "df -h > /dev/null" -e
# Examine /tmp/diskprob, contains only final 10 straces of "df -h > /dev/null"
./ringwrap "df -h > /dev/null" -s # usage statistics
./ringwrap "df -h > /dev/null" -f
/**************************************************
********************* DETAILS *********************
**************************************************/
This program allows an arbitrary wrapper command to be
asynchronously enabled and disabled around an arbitrary
primary command. Once activated, the program will begin
executing the wrapper command with the primary as it's
final argument.
The intended use is, modifying the behavior of the primary
command, from outside of it's execution context. Enabling,
or disabling the wrapping at will, and gathering execution
statistics.
For example, consider a network service that forks a new
server for each connection. You can drop in ringwrap
as the "server" in the configuration once, only to initialize
and/or run limited straces or logging on it later w/o
having to restart or interrupt the service.
The --keep and --outdir options enhance the functionality
by generating a unique output directory and filename for
each run, then purging all but the most recent. The
filename is passed via the magic sequence "@@@" in the
wrapped command.
The filename will be in the form:
/YYYY-MM-DD_HH:MM:SS_PID/
The magic squence is not yet supported for use in the primary
command.
If multiple instances of the same command will be wrapped with
differing output options, the --unique option may be used to
distinguish them.
Shared memory segments and semaphores are used to serialize
access to wrapping state as well as output. This is intended
for cases where hundreds or thousands of wrapped commands
may be executing at the same time.
Report bugs to Chris Evich .