systemd/man/systemd-socket-proxyd.xml
Lennart Poettering 96c374d0a5 socket-proxyd: rename from saproxy
The thing is a daemon, hence needs a "d" prefix. Also, we tend to not
abbreviate names of background components unnecessarily, since they are
not primary commands people type. Then, the fact that this thing does
socket actviation is mostly in implementationd detail for the proxy.

Also, do some minor indenting clean-ups and other code updates.
2013-10-18 02:58:47 +02:00

255 lines
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<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
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Copyright 2013 David Strauss
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<refentry id="systemd-socket-proxyd">
<refentryinfo>
<title>systemd-socket-proxyd</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>David</firstname>
<surname>Strauss</surname>
<email>david@davidstrauss.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-socket-proxyd</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-socket-proxyd</refname>
<refpurpose>Inherit a socket. Bidirectionally
proxy.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-socket-proxyd</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain"><replaceable>HOSTNAME-OR-IP</replaceable></arg>
<arg choice="plain"><replaceable>PORT-OR-SERVICE</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-socket-proxyd</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>systemd-socket-proxyd</command> provides a proxy
to socket-activate services that do not yet support
native socket activation. On behalf of the daemon,
the proxy inherits the socket from systemd, accepts
each client connection, opens a connection to the server
for each client, and then bidirectionally forwards
data between the two.</para>
<para>This utility's behavior is similar to
<citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum> </citerefentry>.
The main differences for <command>systemd-socket-proxyd</command>
are support for socket activation with
<literal>Accept=false</literal> and an event-driven
design that scales better with the number of
connections.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>-h</option></term>
<term><option>--help</option></term>
<listitem>
<para>Prints a short help
text and exits.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<listitem>
<para>Prints a version
string and exits.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--ignore-env</option></term>
<listitem>
<para>Skips verification of
the expected PID and file
descriptor numbers. Use if
invoked indirectly, for
example with a shell script
rather than with
<option>ExecStart=/usr/bin/systemd-socket-proxyd</option>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success 0 is returned, a non-zero failure
code otherwise.</para>
</refsect1>
<refsect1>
<title>Examples</title>
<refsect2>
<title>Direct-Use Example</title>
<para>Use two services with a dependency
and no namespace isolation.</para>
<example label="proxy socket unit">
<title>/etc/systemd/system/proxy-to-nginx.socket</title>
<programlisting>
<![CDATA[[Socket]
ListenStream=80
[Install]
WantedBy=socket.target]]>
</programlisting>
</example>
<example label="proxy service unit">
<title>/etc/systemd/system/proxy-to-nginx.service</title>
<programlisting>
<![CDATA[[Unit]
After=nginx.service
Requires=nginx.service
[Service]
ExecStart=/usr/bin/systemd-socket-proxyd /tmp/nginx.sock
PrivateTmp=true
PrivateNetwork=true]]>
</programlisting>
</example>
<example label="nginx configuration">
<title>/etc/nginx/nginx.conf</title>
<programlisting>
<![CDATA[[...]
server {
listen unix:/tmp/nginx.sock;
[...]]]>
</programlisting>
</example>
<example label="commands">
<programlisting>
<![CDATA[$ sudo systemctl --system daemon-reload
$ sudo systemctl start proxy-to-nginx.socket
$ sudo systemctl enable proxy-to-nginx.socket
$ curl http://localhost:80/]]>
</programlisting>
</example>
</refsect2>
<refsect2>
<title>Indirect-Use Example</title>
<para>Use a shell script to isolate the
service and proxy into the same namespace.
This is particularly useful for running
TCP-only daemons without the daemon
affecting ports on regular
interfaces.</para>
<example label="combined proxy and nginx socket unit">
<title>
/etc/systemd/system/proxy-with-nginx.socket</title>
<programlisting>
<![CDATA[[Socket]
ListenStream=80
[Install]
WantedBy=socket.target]]>
</programlisting>
</example>
<example label="combined proxy and nginx service unit">
<title>
/etc/systemd/system/proxy-with-nginx.service</title>
<programlisting>
<![CDATA[[Unit]
After=syslog.target remote-fs.target nss-lookup.target
[Service]
ExecStartPre=/usr/sbin/nginx -t
ExecStart=/usr/bin/socket-proxyd-nginx.sh
PrivateTmp=true
PrivateNetwork=true]]>
</programlisting>
</example>
<example label="shell script">
<title>
/usr/bin/socket-proxyd-nginx.sh</title>
<programlisting>
<![CDATA[#!/bin/sh
/usr/sbin/nginx
while [ ! -f /tmp/nginx.pid ]
do
/usr/bin/inotifywait /tmp/nginx.pid
done
/usr/bin/systemd-socket-proxyd --ignore-env localhost 8080]]>
</programlisting>
</example>
<example label="nginx configuration">
<title>
/etc/nginx/nginx.conf</title>
<programlisting>
<![CDATA[[...]
server {
listen 8080;
listen unix:/tmp/nginx.sock;
[...]]]>
</programlisting>
</example>
<example label="commands">
<programlisting>
<![CDATA[$ sudo systemctl --system daemon-reload
$ sudo systemctl start proxy-with-nginx.socket
$ sudo systemctl enable proxy-with-nginx.socket
$ curl http://localhost:80/]]>
</programlisting>
</example>
</refsect2>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry>
<refentrytitle>
systemd.service</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>
systemd.socket</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>systemctl</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>socat</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry></para>
</refsect1>
</refentry>