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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-05 22:26:11 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-05 22:26:11 +0000 |
| commit | 90b12bd71bb9fc79a4640b9112c13ef529d0196a (patch) | |
| tree | 523b3f4ee2969e7a729bab2ba749c4b924ae62af /doc/s6-svwait.html | |
| download | s6-90b12bd71bb9fc79a4640b9112c13ef529d0196a.tar.xz | |
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diff --git a/doc/s6-svwait.html b/doc/s6-svwait.html new file mode 100644 index 0000000..6e15704 --- /dev/null +++ b/doc/s6-svwait.html @@ -0,0 +1,73 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>s6: the s6-svwait program</title> + <meta name="Description" content="s6: the s6-svwait program" /> + <meta name="Keywords" content="s6 command s6-svwait notification service waiting" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">s6</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a> +</p> + +<h1> The s6-svwait program </h1> + +<p> +s6-svwait blocks until a collection of supervised services goes up, or down. +</p> + +<p> +s6-svwait only waits for notifications; it never polls. +</p> + +<h2> Interface </h2> + +<pre> + s6-svwait [ -U | -u | -d ] [ -a | -o ] [ -t <em>timeout</em> ] <em>servicedir...</em> +</pre> + +<p> +s6-svwait monitors one or more <a href="servicedir.html">service +directories</a> given as its arguments, waiting for a state (up or down) to +happen. It exits 0 when the wanted condition becomes true. +</p> + +<h2> Options </h2> + +<ul> + <li> <tt>-u</tt> : up. s6-svwait will wait until the services are up, as +reported by s6-supervise. +This is the default; it is not reliable, but it does not depend on specific +support in the service programs. See <a href="notifywhenup.html">this page</a> +for details. </li> + <li> <tt>-U</tt> : really up. s6-svwait will wait until the services are +up, as reported by the services themselves. This requires specific support in the +service programs: see the explanation on <a href="notifywhenup.html">this page</a>. </li> + <li> <tt>-d</tt> : down. s6-svwait will wait until the services are down. </li> + <li> <tt>-o</tt> : or. s6-svwait will wait until <em>one</em> of the +given services comes up or down. </li> + <li> <tt>-a</tt> : and. s6-svwait will wait until <em>all</em> of the +given services come up or down. This is the default. </li> + <li> <tt>-t <em>timeout</em></tt> : if the requested events have not +happened after <em>timeout</em> milliseconds, s6-svwait will print a message +to stderr and exit 1. By default, <em>timeout</em> is 0, which means no time +limit. </li> +</ul> + + +<h2> Internals </h2> + +<p> +s6-svwait spawns a <a href="s6-ftrigrd.html">s6-ftrigrd</a> child to +listen to notifications sent by <a href="s6-supervise.html">s6-supervise</a>. +It also checks <tt>supervise/status</tt> files to get the current service +states, so it is immune to race conditions. +</p> + +</body> +</html> |