man/systemd-notify.xml

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