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+<?xml version="1.0" encoding="UTF-8"?>
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+<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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+"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
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+<!ENTITY mdash "‗" >
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+]>
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+
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+<chapter id="kea-shell">
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+ <title>The Kea Shell</title>
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+
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+ <section id="shell-overview">
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+ <title>Overview</title>
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+ <para>Kea 1.2.0 introduced the Control Agent (CA, see <xref linkend="kea-ctrl-agent"/>) that
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+ provides a RESTful control interface over HTTP. That API is typically expected to be used by
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+ various IPAMs and similar management systems. Nevertheless, there may be cases when you want
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+ to send a command to the CA directly. The Kea Shell provides a way to do this. It is a simple
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+ command-line, scripting-friendly text client that is able connect to the CA, send it commands
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+ with parameters, retrieve the responses and display them.</para>
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+
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+ <para>As the primary purpose of the Kea Shell is as a tool in scripting environment,
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+ it is not interactive. However, with simple tricks it can be run manually.
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+ </para>
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+ </section>
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+
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+ <section id="shell-usage">
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+ <title>Shell Usage</title>
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+ <para><command>kea-shell</command> is run as follows:
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+<screen>
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+kea-shell [--host hostname] [--port number] [--timeout seconds] [command]
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+</screen>
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+ where:
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+ </para>
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+ <itemizedlist>
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+ <listitem>
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+ <simpara>
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+ <command>--host <replaceable>hostname</replaceable></command> specifies the hostname
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+ of the CA. If not specified, "localhost" is used.
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+ </simpara>
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+ </listitem>
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+
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+ <listitem>
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+ <simpara>
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+ <command>--port <replaceable>number</replaceable></command> specifies the TCP port
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+ on which the CA listens. If not specified, 8000 is used.
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+ </simpara>
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+ </listitem>
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+
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+ <listitem>
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+ <simpara>
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+ <command>--timeout <replaceable>seconds</replaceable></command> specifies the
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+ timeout (in seconds) for the connection. If not given, 10 seconds is used.
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+ </simpara>
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+ </listitem>
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+
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+ <listitem>
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+ <simpara>
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+ <command>command</command> specifies the command to be sent. If not specified,
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+ <command>list-commands</command> command is used.
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+ </simpara>
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+ </listitem>
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+ </itemizedlist>
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+
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+ <para>Other switches are:</para>
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+ <itemizedlist>
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+ <listitem>
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+ <simpara>
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+ <command>-h</command> prints a help message.
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+ </simpara>
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+ </listitem>
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+ <listitem>
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+ <simpara>
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+ <command>-v</command> prints the software version.
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+ </simpara>
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+ </listitem>
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+ </itemizedlist>
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+
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+ <para>
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+ Once started, the shell reads parameters for the command from standard input, which are
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+ expected to be in JSON format. When all have been read, the shell establishes a connection
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+ with the CA using HTTP, sends the command and awaits a response. Once that is received,
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+ it is printed on standard output.
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+ </para>
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+
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+ <para>
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+ For a list of available commands, see <xref linkend="ctrl-channel"/>. Additional commands
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+ may be provided by hook libraries. If unsure which commands are supported, use the
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+ <command>list-commands</command> command. It will instruct the CA to return a list of
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+ all supported commands.
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+ </para>
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+
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+ <para>The following shows a simple example of usage:
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+<screen>
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+$ <userinput>kea-shell --host 192.0.2.1 --port 8001 list-commands</userinput>
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+^D
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+</screen>
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+ After the command line is entered, the program waits for command parameters to be entered.
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+ Since <command>list-commands</command> does not take any
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+ arguments, CTRL-D (represented in the above example by "^D") is pressed to indicate end
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+ of file (and so terminate the parameter input). The Shell will then contact
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+ the CA and print out the list of available commands returned.
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+ </para>
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+
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+ <para>It is envisaged that Kea Shell will be most frequently used in scripts. The next example
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+ shows a simple scripted execution. It sends the command "config-write" to the CA, along
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+ with the parameters specified in param.json. The result will be stored in result.json.
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+<screen>
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+$ cat param.json
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+"filename": "my-config-file.json"
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+$ <userinput>cat param.json | kea-shell --host 192.0.2.1 config-write > result.json</userinput>
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+</screen>
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+ </para>
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+
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+ <para>Kea Shell requires Python to to be installed on the system. It was tested with
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+ Python 2.7 and various versions
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+ of Python 3, up to 3.5. Since not every Kea deployment uses this feature and there are
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+ deployments that do not have Python, the Kea Shell is not enabled by default. To use it,
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+ you must specify <command>--enable-shell</command> to when running "configure" during the
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+ installation of Kea.</para>
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+
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+ <para>The Kea Shell is intended to serve more as a demonstration of the RESTful interface
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+ capabilities (and, perhaps, an illustration for people interested in integrating their
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+ management evironments with Kea) than as a serious management client. Do not expect it
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+ to be significantly expanded in the future. It is, and will remain, a simple tool.</para>
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+ </section>
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+</chapter>
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Tomek Mrugalski