summaryrefslogtreecommitdiff
path: root/docs/manual/mod/mod_proxy_express.xml
blob: 3f90683e271573000eb2a86cebb748febae45265 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
<!-- $LastChangedRevision$ -->

<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<modulesynopsis metafile="mod_proxy_express.xml.meta">

<name>mod_proxy_express</name>
<description>Dynamic mass reverse proxy extension for
<module>mod_proxy</module></description>
<status>Extension</status>
<sourcefile>mod_proxy_express.c</sourcefile>
<identifier>proxy_express_module</identifier>
<compatibility>Available in Apache 2.3.13 and later</compatibility>

<summary>
    <p>This module creates dynamically configured mass reverse
    proxies, by mapping the <code>Host:</code> header of the HTTP request to
    a server name and backend URL stored in a DBM file.
    This allows for easy use of a huge number of reverse proxies
    with no configuration changes. It is much less feature-full
    than <module>mod_proxy_balancer</module>, which also provides
    dynamic growth, but is intended to handle much, much
    larger numbers of backends. It is ideally suited as a
    front-end HTTP switch and for micro-services architectures.</p>

    <p>This module <em>requires</em> the service of <module
    >mod_proxy</module>.</p>

    <note type="warning"><title>Warning</title>
      <p>Do not enable proxying until you have <a
      href="mod_proxy.html#access">secured your server</a>. Open proxy
      servers are dangerous both to your network and to the Internet at
      large.</p>
    </note>

<note><title>Limitations</title>
  <ul>
    <li>This module is not intended to replace the dynamic capability of
      <module>mod_proxy_balancer</module>. Instead, it is intended to be mostly
      a lightweight and fast alternative to using <module>mod_rewrite</module>
      with <directive module="mod_rewrite">RewriteMap</directive> and the
      <code>[P]</code> flag for mapped reverse proxying.
    </li>
    <li>It does not support regex or pattern matching at all.
    </li>
    <li>It emulates:
      <highlight language="config">
&lt;VirtualHost *:80&gt;
   ServerName front.end.server
   ProxyPass        "/" "back.end.server:port"
   ProxyPassReverse "/" "back.end.server:port"
&lt;/VirtualHost&gt;
      </highlight>
      That is, the entire URL is appended to the mapped backend
      URL. This is in keeping with the intent of being a simple
      but fast reverse proxy switch.
    </li>
  </ul>
</note>

</summary>
<seealso><module>mod_proxy</module></seealso>
<seealso><directive module="mod_proxy">BalancerMember</directive></seealso>
<seealso><directive module="mod_proxy">BalancerGrowth</directive></seealso>
<seealso><directive module="mod_proxy">BalancerPersist</directive></seealso>
<seealso><directive module="mod_proxy">BalancerInherit</directive></seealso>

<directivesynopsis>
<name>ProxyExpressEnable</name>
<description>Enable the module functionality.</description>
<syntax>ProxyExpressEnable on|off</syntax>
<default>ProxyExpressEnable off</default>
<contextlist><context>server config</context><context>virtual host</context>
  </contextlist>
<override>FileInfo</override>

<usage>
  <p>The <directive>ProxyExpressEnable</directive> directive
    controls whether the module will be active.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>ProxyExpressDBMFile</name>
<description>Pathname to DBM file.</description>
<syntax>ProxyExpressDBMFile <var>pathname</var></syntax>
<contextlist><context>server config</context><context>virtual host</context>
  </contextlist>
<override>FileInfo</override>

<usage>
  <p>The <directive>ProxyExpressDBMFile</directive> directive
    points to the location of the Express map DBM file. This
    file serves to map the incoming server name, obtained from
    the <code>Host:</code> header, to a backend URL.</p>

    <note><title>Note</title>
      <p>The file is constructed from a plain text file format using
        the <code><a href="../programs/httxt2dbm.html">httxt2dbm</a></code>
        utility.</p>

      <example><title>ProxyExpress map file</title>
        ##<br />
        ##express-map.txt:<br />
        ##<br />
        <br />
        www1.example.com   http://192.168.211.2:8080<br />
        www2.example.com   http://192.168.211.12:8088<br />
        www3.example.com   http://192.168.212.10<br />
      </example>

      <example><title>Create DBM file</title>
        httxt2dbm -i express-map.txt -o emap<br />
      </example>

      <example><title>Configuration</title>
      <highlight language="config">
ProxyExpressEnable on
ProxyExpressDBMFile emap
      </highlight>
      </example>
    </note>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>ProxyExpressDBMType</name>
<description>DBM type of file.</description>
<syntax>ProxyExpressDBMType <var>type</var></syntax>
<default>ProxyExpressDBMType default</default>
<contextlist><context>server config</context><context>virtual host</context>
  </contextlist>
<override>FileInfo</override>

<usage>
  <p>The <directive>ProxyExpressDBMType</directive> directive
    controls the DBM type expected by the module. The default
    is the default DBM type created with <code>
    <a href="../programs/httxt2dbm.html">httxt2dbm</a></code>.</p>
    <p>Possible values are (not all may be available at run time):</p>
<table border="1" style="zebra">
    <columnspec><column width=".3"/><column width=".7"/></columnspec>

    <tr><th>Value</th><th>Description</th></tr>
    <tr><td><code>db</code></td><td> Berkeley DB files</td></tr>
    <tr><td><code>gdbm</code></td><td> GDBM files</td></tr>
    <tr><td><code>ndbm</code></td><td> NDBM files</td></tr>
    <tr><td><code>sdbm</code></td><td> SDBM files (always available)</td></tr>
    <tr><td><code>default</code></td><td> default DBM type</td></tr>
    </table>

</usage>
</directivesynopsis>

</modulesynopsis>