Mercurial > hg > nginx-site
view xml/en/docs/http/ngx_http_memcached_module.xml @ 1517:53ae63cb4cfa
Added the limit_conn module for stream.
author | Yaroslav Zhuravlev <yar@nginx.com> |
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date | Thu, 18 Jun 2015 21:04:07 +0300 |
parents | 91a064bdb4f9 |
children | c4c1dddfedac |
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<?xml version="1.0"?> <!-- Copyright (C) Igor Sysoev Copyright (C) Nginx, Inc. --> <!DOCTYPE module SYSTEM "../../../../dtd/module.dtd"> <module name="Module ngx_http_memcached_module" link="/en/docs/http/ngx_http_memcached_module.html" lang="en" rev="10"> <section id="summary"> <para> The <literal>ngx_http_memcached_module</literal> module is used to obtain responses from a memcached server. The key is set in the <var>$memcached_key</var> variable. A response should be put in memcached in advance by means external to nginx. </para> </section> <section id="example" name="Example Configuration"> <para> <example> server { location / { set $memcached_key "$uri?$args"; memcached_pass host:11211; error_page 404 502 504 = @fallback; } location @fallback { proxy_pass http://backend; } } </example> </para> </section> <section id="directives" name="Directives"> <directive name="memcached_bind"> <syntax><value>address</value> | <literal>off</literal></syntax> <default/> <context>http</context> <context>server</context> <context>location</context> <appeared-in>0.8.22</appeared-in> <para> Makes outgoing connections to a memcached server originate from the specified local IP <value>address</value>. Parameter value can contain variables (1.3.12). The special value <literal>off</literal> (1.3.12) cancels the effect of the <literal>memcached_bind</literal> directive inherited from the previous configuration level, which allows the system to auto-assign the local IP address. </para> </directive> <directive name="memcached_buffer_size"> <syntax><value>size</value></syntax> <default>4k|8k</default> <context>http</context> <context>server</context> <context>location</context> <para> Sets the <value>size</value> of the buffer used for reading the response received from the memcached server. The response is passed to the client synchronously, as soon as it is received. </para> </directive> <directive name="memcached_connect_timeout"> <syntax><value>time</value></syntax> <default>60s</default> <context>http</context> <context>server</context> <context>location</context> <para> Defines a timeout for establishing a connection with a memcached server. It should be noted that this timeout cannot usually exceed 75 seconds. </para> </directive> <directive name="memcached_force_ranges"> <syntax><literal>on</literal> | <literal>off</literal></syntax> <default>off</default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>1.7.7</appeared-in> <para> Enables byte-range support for both cached and uncached responses from the memcached server regardless of the <header>Accept-Ranges</header> field in these responses. </para> </directive> <directive name="memcached_gzip_flag"> <syntax><value>flag</value></syntax> <default></default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>1.3.6</appeared-in> <para> Enables the test for the <value>flag</value> presence in the memcached server response and sets the “<literal>Content-Encoding</literal>” response header field to “<literal>gzip</literal>” if the flag is set. </para> </directive> <directive name="memcached_next_upstream"> <syntax> <literal>error</literal> | <literal>timeout</literal> | <literal>invalid_response</literal> | <literal>not_found</literal> | <literal>off</literal> ...</syntax> <default>error timeout</default> <context>http</context> <context>server</context> <context>location</context> <para> Specifies in which cases a request should be passed to the next server: <list type="tag"> <tag-name><literal>error</literal></tag-name> <tag-desc>an error occurred while establishing a connection with the server, passing a request to it, or reading the response header;</tag-desc> <tag-name><literal>timeout</literal></tag-name> <tag-desc>a timeout has occurred while establishing a connection with the server, passing a request to it, or reading the response header;</tag-desc> <tag-name><literal>invalid_response</literal></tag-name> <tag-desc>a server returned an empty or invalid response;</tag-desc> <tag-name><literal>not_found</literal></tag-name> <tag-desc>a response was not found on the server;</tag-desc> <tag-name><literal>off</literal></tag-name> <tag-desc>disables passing a request to the next server.</tag-desc> </list> </para> <para> One should bear in mind that passing a request to the next server is only possible if nothing has been sent to a client yet. That is, if an error or timeout occurs in the middle of the transferring of a response, fixing this is impossible. </para> <para> The directive also defines what is considered an <link doc="ngx_http_upstream_module.xml" id="max_fails">unsuccessful attempt</link> of communication with a server. The cases of <literal>error</literal>, <literal>timeout</literal> and <literal>invalid_header</literal> are always considered unsuccessful attempts, even if they are not specified in the directive. The case of <literal>not_found</literal> is never considered an unsuccessful attempt. </para> <para> Passing a request to the next server can be limited by <link id="memcached_next_upstream_tries">the number of tries</link> and by <link id="memcached_next_upstream_timeout">time</link>. </para> </directive> <directive name="memcached_next_upstream_timeout"> <syntax><value>time</value></syntax> <default>0</default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>1.7.5</appeared-in> <para> Limits the time allowed to pass a request to the <link id="memcached_next_upstream">next server</link>. The <literal>0</literal> value turns off this limitation. </para> </directive> <directive name="memcached_next_upstream_tries"> <syntax><value>number</value></syntax> <default>0</default> <context>http</context> <context>server</context> <context>location</context> <appeared-in>1.7.5</appeared-in> <para> Limits the number of possible tries for passing a request to the <link id="memcached_next_upstream">next server</link>. The <literal>0</literal> value turns off this limitation. </para> </directive> <directive name="memcached_pass"> <syntax><value>address</value></syntax> <default/> <context>location</context> <context>if in location</context> <para> Sets the memcached server address. The address can be specified as a domain name or an address, and a port: <example> memcached_pass localhost:11211; </example> or as a UNIX-domain socket path: <example> memcached_pass unix:/tmp/memcached.socket; </example> </para> <para> If a domain name resolves to several addresses, all of them will be used in a round-robin fashion. In addition, an address can be specified as a <link doc="ngx_http_upstream_module.xml">server group</link>. </para> </directive> <directive name="memcached_read_timeout"> <syntax><value>time</value></syntax> <default>60s</default> <context>http</context> <context>server</context> <context>location</context> <para> Defines a timeout for reading a response from the memcached server. The timeout is set only between two successive read operations, not for the transmission of the whole response. If the memcached server does not transmit anything within this time, the connection is closed. </para> </directive> <directive name="memcached_send_timeout"> <syntax><value>time</value></syntax> <default>60s</default> <context>http</context> <context>server</context> <context>location</context> <para> Sets a timeout for transmitting a request to the memcached server. The timeout is set only between two successive write operations, not for the transmission of the whole request. If the memcached server does not receive anything within this time, the connection is closed. </para> </directive> </section> <section id="variables" name="Embedded Variables"> <para> <list type="tag"> <tag-name id="var_memcached_key"><var>$memcached_key</var></tag-name> <tag-desc> Defines a key for obtaining response from a memcached server. </tag-desc> </list> </para> </section> </module>