man/systemd-notify.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
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   6   This file is part of systemd.
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   8   Copyright 2010 Lennart Poettering
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  23
  24 <refentry id="systemd-notify"
  25           xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27         <refentryinfo>
  28                 <title>systemd-notify</title>
  29                 <productname>systemd</productname>
  30
  31                 <authorgroup>
  32                         <author>
  33                                 <contrib>Developer</contrib>
  34                                 <firstname>Lennart</firstname>
  35                                 <surname>Poettering</surname>
  36                                 <email>lennart@poettering.net</email>
  37                         </author>
  38                 </authorgroup>
  39         </refentryinfo>
  40
  41         <refmeta>
  42                 <refentrytitle>systemd-notify</refentrytitle>
  43                 <manvolnum>1</manvolnum>
  44         </refmeta>
  45
  46         <refnamediv>
  47                 <refname>systemd-notify</refname>
  48                 <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
  49         </refnamediv>
  50
  51         <refsynopsisdiv>
  52                 <cmdsynopsis>
  53                         <command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
  54                 </cmdsynopsis>
  55         </refsynopsisdiv>
  56
  57         <refsect1>
  58                 <title>Description</title>
  59
  60                 <para><command>systemd-notify</command> may be
  61                 called by daemon scripts to notify the init system
  62                 about status changes. It can be used to send arbitrary
  63                 information, encoded in an environment-block-like list
  64                 of strings. Most importantly it can be used for
  65                 start-up completion notification.</para>
  66
  67                 <para>This is mostly just a wrapper around
  68                 <function>sd_notify()</function> and makes this
  69                 functionality available to shell scripts. For details
  70                 see
  71                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  72
  73                 <para>The command line may carry a list of
  74                 environment variables to send as part of the status
  75                 update.</para>
  76
  77                 <para>Note that systemd will refuse reception of
  78                 status updates from this command unless
  79                 <varname>NotifyAccess=all</varname> is set for the
  80                 service unit this command is called from.</para>
  81
  82         </refsect1>
  83
  84         <refsect1>
  85                 <title>Options</title>
  86
  87                 <para>The following options are understood:</para>
  88
  89                 <variablelist>
  90                         <varlistentry>
  91                                 <term><option>--ready</option></term>
  92
  93                                 <listitem><para>Inform the init system
  94                                 about service start-up
  95                                 completion. This is equivalent to
  96                                 <command>systemd-notify
  97                                 READY=1</command>. For details about
  98                                 the semantics of this option see
  99                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 100                         </varlistentry>
 101
 102                         <varlistentry>
 103                                 <term><option>--pid=</option></term>
 104
 105                                 <listitem><para>Inform the init system
 106                                 about the main PID of the
 107                                 daemon. Takes a PID as argument. If
 108                                 the argument is omitted, the PID of the
 109                                 process that invoked
 110                                 <command>systemd-notify</command> is
 111                                 used. This is equivalent to
 112                                 <command>systemd-notify
 113                                 MAINPID=$PID</command>. For details
 114                                 about the semantics of this option see
 115                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 116                         </varlistentry>
 117
 118                         <varlistentry>
 119                                 <term><option>--status=</option></term>
 120
 121                                 <listitem><para>Send a free-form
 122                                 status string for the daemon to the
 123                                 init systemd. This option takes the
 124                                 status string as argument. This is
 125                                 equivalent to <command>systemd-notify
 126                                 STATUS=...</command>. For details
 127                                 about the semantics of this option see
 128                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 129                         </varlistentry>
 130
 131                         <varlistentry>
 132                                 <term><option>--booted</option></term>
 133
 134                                 <listitem><para>Returns 0 if the
 135                                 system was booted up with systemd,
 136                                 non-zero otherwise. If this option is
 137                                 passed, no message is sent. This option
 138                                 is hence unrelated to the other
 139                                 options. For details about the
 140                                 semantics of this option, see
 141                                 <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 142                         </varlistentry>
 143
 144                         <varlistentry>
 145                                 <term><option>--readahead=</option></term>
 146
 147                                 <listitem><para>Controls disk
 148                                 read-ahead operations. The argument
 149                                 must be a string, and either "cancel",
 150                                 "done" or "noreplay". For details
 151                                 about the semantics of this option see
 152                                 <citerefentry><refentrytitle>sd_readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 153                         </varlistentry>
 154
 155                         <xi:include href="standard-options.xml" xpointer="help" />
 156                         <xi:include href="standard-options.xml" xpointer="version" />
 157                 </variablelist>
 158
 159         </refsect1>
 160
 161         <refsect1>
 162                 <title>Exit status</title>
 163
 164                 <para>On success, 0 is returned, a non-zero failure
 165                 code otherwise.</para>
 166         </refsect1>
 167
 168         <refsect1>
 169                 <title>Example</title>
 170
 171                 <example>
 172                         <title>Start-up Notification and Status Updates</title>
 173
 174                         <para>A simple shell daemon that sends
 175                         start-up notifications after having set up its
 176                         communication channel. During runtime it sends
 177                         further status updates to the init
 178                         system:</para>
 179
 180                         <programlisting>#!/bin/bash
 181
 182 mkfifo /tmp/waldo
 183 systemd-notify --ready --status="Waiting for data..."
 184
 185 while : ; do
 186         read a &lt; /tmp/waldo
 187         systemd-notify --status="Processing $a"
 188
 189         # Do something with $a ...
 190
 191         systemd-notify --status="Waiting for data..."
 192 done</programlisting>
 193                 </example>
 194         </refsect1>
 195
 196         <refsect1>
 197                 <title>See Also</title>
 198                 <para>
 199                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 200                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 201                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 202                         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 203                         <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 204                 </para>
 205         </refsect1>
 206
 207 </refentry>