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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-19 15:01:58 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-09-19 15:01:58 +0000 |
| commit | 54b6467013bfbdb3ee606961c02fbff1271ca582 (patch) | |
| tree | e3969743e61542979f12fca01017e67c4480eca8 /doc/s6-logwatch.html | |
| download | s6-linux-utils-54b6467013bfbdb3ee606961c02fbff1271ca582.tar.xz | |
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diff --git a/doc/s6-logwatch.html b/doc/s6-logwatch.html new file mode 100644 index 0000000..5075d83 --- /dev/null +++ b/doc/s6-logwatch.html @@ -0,0 +1,72 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>s6-linux-utils: the s6-logwatch program</title> + <meta name="Description" content="s6-linux-utils: the s6-logwatch program" /> + <meta name="Keywords" content="s6-linux-utils linux utilities log s6-log logwatch" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">s6-linux-utils</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a> +</p> + +<h1> The <tt>s6-logwatch</tt> program </h1> + +<p> +<tt>s6-logwatch</tt> watches the <tt>current</tt> file of a logdir, printing it +in real time. +</p> + +<h2> Interface </h2> + +<pre> + s6-logwatch [ -m <em>buflen</em> ] <em>logdir</em> +</pre> + +<ul> + <li> s6-logwatch prints <em>logdir</em><tt>/current</tt> and watches +the file. </li> + <li> <em>logdir</em> must be managed by a +<a href="http://skarnet.org/software/s6/s6-log.html">s6-log</a> instance. </li> + <li> When new logs are appended to the <tt>current</tt> file, s6-logwatch prints +them in real-time to stdout. </li> + <li> When a rotation happens, s6-logwatch notices, and keeps watching the +new <tt>current</tt> file. </li> + <li> s6-logwatch runs forever until killed. </li> +</ul> + +<h2> Options </h2> + +<ul> + <li> <tt>-m</tt> <em>buflen</em> : accumulate at most <em>buflen</em> +bytes into the stdout buffer before flushing it. By default, <em>buflen</em> is +4000. </li> +</ul> + +<h2> Bugs </h2> + +<ul> + <li> s6-logwatch is not entirely reliable because there is an unavoidable +race condition when a rotation occurs; it's a hack for humans to keep reading +logs across rotations, not a tool to be used in safe programming. When the +race condition is triggered, s6-logwatch will be unable to understand what +state <em>logdir</em> is in and will exit 101 with an error message. </li> + <li> Specific support in the logger program would be needed to avoid this +race condition; it would significantly bloat the logger program, so it has +not been deemed useful. </li> +</ul> + +<h2> Notes </h2> + +<ul> + <li> s6-logwatch is Linux-specific because it uses the +<a href="http://inotify.aiken.cz/">inotify</a> interface. </li> +</ul> + +</body> +</html> |