Apache+mod_jk+tomcat 配置

首先雖然這個mod_jk已通過時，但仍是放出來你們一塊兒學習一下，文章主要分三部份內容：

1.第一部分：說明主要配置過程

2.第二部分：貼出個人httpd.conf文件

3.第三部分：對mod_jk代碼講解(來源百度)

 

第一部分：配置

1.       準備環境：

操做系統：windows7

httpd-2.2.21-win32-x86-no_ssl.msi

apache-tomcat-6.0.7

apache-tomcat-5.0.7

tomcat-connectors-1.2.32-windows-i386-httpd-2.2.x

jdk1.5

2.       下載APACHE

這裏下載的是APACHE2.2.21版本

3.       下載JK(Tomcat Connector)

Jk是apache和tomcat的鏈接器，也能夠作負載均衡器，主要是apache經過jk找到tomcat。

下載地址：http://archive.apache.org/dist/tomcat/tomcat-connectors/jk/binaries/windows/

Jk的版本要與apache的版本對應如：mod_jk-1.2.32-httpd-2.2.x.zip其匹配的Apache爲2.2.版本以上可用

4.       下載TOMCAT

apache-tomcat-6.0.7.rar

5.       配置修改過程

1)  Apache配置

將Tomcat Connector文件mod_jk.so拷貝到Apache安裝目錄的modules目錄下。

在Apache安裝目錄下找到conf/httpd.conf文件，使用文本編輯器打開：

僞靜態修改

將註釋放開

找到AllowOverride None 將其修改成 All 內容以下：

<Directory />

    Options FollowSymLinks

    AllowOverride All

    Order deny,allow

    Deny from all

</Directory>

Tomcat Connector關聯項增長

        在LoadModules末尾處增長一下內容：

#加載mod_jk鏈接

LoadModule jk_module modules/mod_jk.so

### 配置 mod_jk

JkWorkersFile "conf\workers.properties" #加載集羣中的workers

#此處是指定分配給tomcat的請求 例如*.do *.jsp

JkMount /*.jsp controller

JkLogFile logs/mod_jk.log #指定jk的日誌輸出文件

JkLogLevel warn #指定日誌級別

    找到IfModule dir_module 修改默認訪問地址，須要根據具體項目實際狀況填寫，我這裏使用的是index.jsp 修改以下：

<IfModule dir_module>

DirectoryIndex index.jsp

</IfModule>

    找到Virtual hosts 去掉虛擬主機註釋

# Virtual hosts

#Include conf/extra/httpd-vhosts.conf 將 「#」去掉

Include conf/extra/httpd-vhosts.conf

加載代理(暫時未去掉)

#LoadModule proxy_module modules/mod_proxy.so

#LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

#LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

#LoadModule proxy_connect_module modules/mod_proxy_connect.so

#LoadModule proxy_ftp_module modules/mod_proxy_ftp.so

2)  Tomcat Connector配置

在Apache配置目錄Apache2.2\conf建立workers.properties配置文件，該文件主要用於配置Apache與Tomcat的集成要用到的Tomcat實例和負載均衡分發控制器。

Workers.properties文件放置一下內容；

#下面是分發控制器 注意不要放tomcat實例

worker.list=lbcontroller



#Tomcat1實例配置 這裏要和Tomcat配置文件Service.xml的jvmRoute保持一致

worker.test1.host=localhost

worker.test1.port=8009

worker.test1.type=ajp13

#分發權重 值越大負載越大

worker.tomcat1.lbfactor=1



#Tomcat2實例配置

worker.test2.host=localhost

worker.test2.port=9009

worker.test2.type=ajp13

#分發權重 值越大負載越大

worker.tomcat2.lbfactor=1



#負載均衡分發控制器

worker.lbcontroller.type=lb

worker.lbcontroller.balance_workers=test1,test2

Tomcat配置文件Service.xml主要注意兩個地方，一個是Engine節點須要增長節點標識jvmRoute，一個是將本來註釋掉的Session複製節點改成有效。具體以下：

  

<!--jvmRoute在各個Tomcat配置中不能重複且要與worker.properties文件中的名稱一致-->

    <Engine name="Catalina" defaultHost="localhost" jvmRoute="test1">



<!--session複製內容-->

       <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"

                 channelSendOptions="8">

          <Manager className="org.apache.catalina.ha.session.DeltaManager"

                   expireSessionsOnShutdown="false"

                   notifyListenersOnReplication="true"/>



<Channel className="org.apache.catalina.tribes.group.GroupChannel">

<Membership className="org.apache.catalina.tribes.membership.McastService"

                        address="228.0.0.4"

                        port="45564"

                        frequency="500"

                        dropTime="3000"/>

<Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"

                      address="auto"

                      port="4000"

                      autoBind="100"

                      selectorTimeout="5000"

                      maxThreads="6"/>

            <!-- timeout="60000"-->

            <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">

              <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender" />

            </Sender>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/>

            <Interceptor className="org.apache.catalina.tribes.group.interceptors.ThroughputInterceptor"/>

          </Channel>

          <!--過濾的文件-->

          <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"  filter=".*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.htm;.*\.html;.*\.css;.*\.txt;"/>

          <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve"/>



          <Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"

                    tempDir="/tmp/war-temp/"

                    deployDir="/tmp/war-deploy/"

                    watchDir="/tmp/war-listen/"

                    watchEnabled="false"/>

          <ClusterListener className="org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener"/>

          <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>

        </Cluster>

      <!--session複製內容-->

            <!—Host節點增長一下內容表示站點根路徑-->

<Context path="/sc" docBase="." privileged="true"/>

咱們分別將兩個Tomcat配置文件中的jvmRoute設置爲tomcat一、tomcat2，Server節點 端口分別配置爲8005和9005， Connector節點端口分別配置爲8080和9090，AJPConnector端口分別配置爲8009和9009，Connector端口配置參照單主機多站點場景。請注意兩個Tomcat配置文件Host節點的域名配置必須同樣，Server.xml中的jvmRoute名稱必須和worker.properties中的tomcat實例名稱一致，否則沒法實現session_stricky。

 

*****************************************************************************

 若是須要實現session 複製 須要在Tomcat 下conf/web.xml 中加上<distributable/>

<?xml version="1.0" encoding="ISO-8859-1"?>

省略N多代碼。。。。。。

    <welcome-file-list>

        <welcome-file>index.html</welcome-file>

        <welcome-file>index.htm</welcome-file>

        <welcome-file>index.jsp</welcome-file>

    </welcome-file-list>

<distributable/>

</web-app>

*****************************************************************************

第二部分：httpd.conf文件

#
# This is the main Apache HTTP server configuration file.  It contains the
# configuration directives that give the server its instructions.
# See <URL:http://httpd.apache.org/docs/2.2> for detailed information.
# In particular, see
# <URL:http://httpd.apache.org/docs/2.2/mod/directives.html>
# for a discussion of each configuration directive.
#
# Do NOT simply read the instructions in here without understanding
# what they do.  They're here only as hints or reminders.  If you are unsure
# consult the online docs. You have been warned.
#
# Configuration and logfile names: If the filenames you specify for many
# of the server's control files begin with "/" (or "drive:/" for Win32), the
# server will use that explicit path.  If the filenames do *not* begin
# with "/", the value of ServerRoot is prepended -- so "logs/foo.log"
# with ServerRoot set to "D:/Program Files/Apache Software Foundation/Apache2.2" will be interpreted by the
# server as "D:/Program Files/Apache Software Foundation/Apache2.2/logs/foo.log".
#
# NOTE: Where filenames are specified, you must use forward slashes
# instead of backslashes (e.g., "c:/apache" instead of "c:\apache").
# If a drive letter is omitted, the drive on which httpd.exe is located
# will be used by default.  It is recommended that you always supply
# an explicit drive letter in absolute paths to avoid confusion.

#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# Do not add a slash at the end of the directory path.  If you point
# ServerRoot at a non-local disk, be sure to point the LockFile directive
# at a local disk.  If you wish to share the same ServerRoot for multiple
# httpd daemons, you will need to change at least LockFile and PidFile.
#
ServerRoot "D:/Program Files/Apache Software Foundation/Apache2.2"

#
# Listen: Allows you to bind Apache to specific IP addresses and/or
# ports, instead of the default. See also the <VirtualHost>
# directive.
#
# Change this to Listen on specific IP addresses as shown below to
# prevent Apache from glomming onto all bound IP addresses.
#
#Listen 12.34.56.78:80
Listen 8080

#
# Dynamic Shared Object (DSO) Support
#
# To be able to use the functionality of a module which was built as a DSO you
# have to place corresponding `LoadModule' lines at this location so the
# directives contained in it are actually available _before_ they are used.
# Statically compiled modules (those listed by `httpd -l') do not need
# to be loaded here.
#
# Example:
# LoadModule foo_module modules/mod_foo.so
#
LoadModule actions_module modules/mod_actions.so
LoadModule alias_module modules/mod_alias.so
LoadModule asis_module modules/mod_asis.so
LoadModule auth_basic_module modules/mod_auth_basic.so
#LoadModule auth_digest_module modules/mod_auth_digest.so
#LoadModule authn_alias_module modules/mod_authn_alias.so
#LoadModule authn_anon_module modules/mod_authn_anon.so
#LoadModule authn_dbd_module modules/mod_authn_dbd.so
#LoadModule authn_dbm_module modules/mod_authn_dbm.so
LoadModule authn_default_module modules/mod_authn_default.so
LoadModule authn_file_module modules/mod_authn_file.so
#LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
#LoadModule authz_dbm_module modules/mod_authz_dbm.so
LoadModule authz_default_module modules/mod_authz_default.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_host_module modules/mod_authz_host.so
#LoadModule authz_owner_module modules/mod_authz_owner.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule autoindex_module modules/mod_autoindex.so
#LoadModule cache_module modules/mod_cache.so
#LoadModule cern_meta_module modules/mod_cern_meta.so
LoadModule cgi_module modules/mod_cgi.so
#LoadModule charset_lite_module modules/mod_charset_lite.so
#LoadModule dav_module modules/mod_dav.so
#LoadModule dav_fs_module modules/mod_dav_fs.so
#LoadModule dav_lock_module modules/mod_dav_lock.so
#LoadModule dbd_module modules/mod_dbd.so
#LoadModule deflate_module modules/mod_deflate.so
LoadModule dir_module modules/mod_dir.so
#LoadModule disk_cache_module modules/mod_disk_cache.so
#LoadModule dumpio_module modules/mod_dumpio.so
LoadModule env_module modules/mod_env.so
#LoadModule expires_module modules/mod_expires.so
#LoadModule ext_filter_module modules/mod_ext_filter.so
#LoadModule file_cache_module modules/mod_file_cache.so
#LoadModule filter_module modules/mod_filter.so
#LoadModule headers_module modules/mod_headers.so
#LoadModule ident_module modules/mod_ident.so
#LoadModule imagemap_module modules/mod_imagemap.so
LoadModule include_module modules/mod_include.so
#LoadModule info_module modules/mod_info.so
LoadModule isapi_module modules/mod_isapi.so
#LoadModule ldap_module modules/mod_ldap.so
#LoadModule logio_module modules/mod_logio.so
LoadModule log_config_module modules/mod_log_config.so
#LoadModule log_forensic_module modules/mod_log_forensic.so
#LoadModule mem_cache_module modules/mod_mem_cache.so
LoadModule mime_module modules/mod_mime.so
#LoadModule mime_magic_module modules/mod_mime_magic.so
LoadModule negotiation_module modules/mod_negotiation.so
#LoadModule proxy_module modules/mod_proxy.so
#LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
#LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
#LoadModule proxy_connect_module modules/mod_proxy_connect.so
#LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
#LoadModule proxy_http_module modules/mod_proxy_http.so
#LoadModule proxy_scgi_module modules/mod_proxy_scgi.so
#LoadModule reqtimeout_module modules/mod_reqtimeout.so
#url僞靜態
LoadModule rewrite_module modules/mod_rewrite.so
LoadModule setenvif_module modules/mod_setenvif.so
#LoadModule speling_module modules/mod_speling.so
#LoadModule ssl_module modules/mod_ssl.so
#LoadModule status_module modules/mod_status.so
#LoadModule substitute_module modules/mod_substitute.so
#LoadModule unique_id_module modules/mod_unique_id.so
#LoadModule userdir_module modules/mod_userdir.so
#LoadModule usertrack_module modules/mod_usertrack.so
#LoadModule version_module modules/mod_version.so
#LoadModule vhost_alias_module modules/mod_vhost_alias.so

#加載mod_jk鏈接
LoadModule jk_module modules/mod_jk.so
#加載集羣中的workers
JkWorkersFile "conf/workers.properties"
#此處是指定分配給tomcat的請求 例如*.do *.jsp
JkMount /*.jsp lbcontroller
#指定jk的日誌輸出文件
JkLogFile "logs/mod_jk.log"
#指定日誌級別
JkLogLevel warn




<IfModule !mpm_netware_module>
<IfModule !mpm_winnt_module>
#
# If you wish httpd to run as a different user or group, you must run
# httpd as root initially and it will switch.
#
# User/Group: The name (or #number) of the user/group to run httpd as.
# It is usually good practice to create a dedicated user and group for
# running httpd, as with most system services.
#
User daemon
Group daemon

</IfModule>
</IfModule>

# 'Main' server configuration
#
# The directives in this section set up the values used by the 'main'
# server, which responds to any requests that aren't handled by a
# <VirtualHost> definition.  These values also provide defaults for
# any <VirtualHost> containers you may define later in the file.
#
# All of these directives may appear inside <VirtualHost> containers,
# in which case these default settings will be overridden for the
# virtual host being defined.
#

#
# ServerAdmin: Your address, where problems with the server should be
# e-mailed.  This address appears on some server-generated pages, such
# as error documents.  e.g. admin@your-domain.com
#
ServerAdmin localhost

#
# ServerName gives the name and port that the server uses to identify itself.
# This can often be determined automatically, but we recommend you specify
# it explicitly to prevent problems during startup.
#
# If your host doesn't have a registered DNS name, enter its IP address here.
#
ServerName localhost:8080
#
# DocumentRoot: The directory out of which you will serve your
# documents. By default, all requests are taken from this directory, but
# symbolic links and aliases may be used to point to other locations.
#
DocumentRoot "D:/work/work_bz/test/WebRoot"
#
# Each directory to which Apache has access can be configured with respect
# to which services and features are allowed and/or disabled in that
# directory (and its subdirectories).
#
# First, we configure the "default" to be a very restrictive set of
# features.
#    默認爲 AllowOverride None
<Directory />
    Options FollowSymLinks
    AllowOverride All
    #Order deny,allow
      #Deny from all
       Order allow,deny
    Allow from all
    Satisfy all
</Directory>

#首次訪問頁面
<IfModule dir_module>
    DirectoryIndex index.jsp
</IfModule>

#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<FilesMatch "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy All
</FilesMatch>

#
# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here.  If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog "logs/error.log"

#
# LogLevel: Control the number of messages logged to the error_log.
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
#
LogLevel warn

<IfModule log_config_module>
    #
    # The following directives define some format nicknames for use with
    # a CustomLog directive (see below).
    #
    LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
    LogFormat "%h %l %u %t \"%r\" %>s %b" common

    <IfModule logio_module>
      # You need to enable mod_logio.c to use %I and %O
      LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
    </IfModule>

    #
    # The location and format of the access logfile (Common Logfile Format).
    # If you do not define any access logfiles within a <VirtualHost>
    # container, they will be logged here.  Contrariwise, if you *do*
    # define per-<VirtualHost> access logfiles, transactions will be
    # logged therein and *not* in this file.
    #
    CustomLog "logs/access.log" common

    #
    # If you prefer a logfile with access, agent, and referer information
    # (Combined Logfile Format) you can use the following directive.
    #
    #CustomLog "logs/access.log" combined
</IfModule>

<IfModule alias_module>
    #
    # Redirect: Allows you to tell clients about documents that used to
    # exist in your server's namespace, but do not anymore. The client
    # will make a new request for the document at its new location.
    # Example:
    # Redirect permanent /foo http://192.168.12.242/bar

    #
    # Alias: Maps web paths into filesystem paths and is used to
    # access content that does not live under the DocumentRoot.
    # Example:
    # Alias /webpath /full/filesystem/path
    #
    # If you include a trailing / on /webpath then the server will
    # require it to be present in the URL.  You will also likely
    # need to provide a <Directory> section to allow access to
    # the filesystem path.

    #
    # ScriptAlias: This controls which directories contain server scripts.
    # ScriptAliases are essentially the same as Aliases, except that
    # documents in the target directory are treated as applications and
    # run by the server when requested rather than as documents sent to the
    # client.  The same rules about trailing "/" apply to ScriptAlias
    # directives as to Alias.
    #
    ScriptAlias /cgi-bin/ "D:/Program Files/Apache Software Foundation/Apache2.2/cgi-bin/"

</IfModule>

<IfModule cgid_module>
    #
    # ScriptSock: On threaded servers, designate the path to the UNIX
    # socket used to communicate with the CGI daemon of mod_cgid.
    #
    #Scriptsock logs/cgisock
</IfModule>

#
# "D:/Program Files/Apache Software Foundation/Apache2.2/cgi-bin" should be changed to whatever your ScriptAliased
# CGI directory exists, if you have that configured.
#
<Directory "D:/Program Files/Apache Software Foundation/Apache2.2/cgi-bin">
    AllowOverride None
    Options None
    Order allow,deny
    Allow from all
</Directory>

#
# DefaultType: the default MIME type the server will use for a document
# if it cannot otherwise determine one, such as from filename extensions.
# If your server contains mostly text or HTML documents, "text/plain" is
# a good value.  If most of your content is binary, such as applications
# or images, you may want to use "application/octet-stream" instead to
# keep browsers from trying to display binary files as though they are
# text.
#
DefaultType text/plain

<IfModule mime_module>
    #
    # TypesConfig points to the file containing the list of mappings from
    # filename extension to MIME-type.
    #
    TypesConfig conf/mime.types

    #
    # AddType allows you to add to or override the MIME configuration
    # file specified in TypesConfig for specific file types.
    #
    #AddType application/x-gzip .tgz
    #
    # AddEncoding allows you to have certain browsers uncompress
    # information on the fly. Note: Not all browsers support this.
    #
    #AddEncoding x-compress .Z
    #AddEncoding x-gzip .gz .tgz
    #
    # If the AddEncoding directives above are commented-out, then you
    # probably should define those extensions to indicate media types:
    #
    AddType application/x-compress .Z
    AddType application/x-gzip .gz .tgz

    #
    # AddHandler allows you to map certain file extensions to "handlers":
    # actions unrelated to filetype. These can be either built into the server
    # or added with the Action directive (see below)
    #
    # To use CGI scripts outside of ScriptAliased directories:
    # (You will also need to add "ExecCGI" to the "Options" directive.)
    #
    #AddHandler cgi-script .cgi

    # For type maps (negotiated resources):
    #AddHandler type-map var

    #
    # Filters allow you to process content before it is sent to the client.
    #
    # To parse .shtml files for server-side includes (SSI):
    # (You will also need to add "Includes" to the "Options" directive.)
    #
    #AddType text/html .shtml
    #AddOutputFilter INCLUDES .shtml
</IfModule>

#
# The mod_mime_magic module allows the server to use various hints from the
# contents of the file itself to determine its type.  The MIMEMagicFile
# directive tells the module where the hint definitions are located.
#
#MIMEMagicFile conf/magic

#
# Customizable error responses come in three flavors:
# 1) plain text 2) local redirects 3) external redirects
#
# Some examples:
#ErrorDocument 500 "The server made a boo boo."
#ErrorDocument 404 /missing.html
#ErrorDocument 404 "/cgi-bin/missing_handler.pl"
#ErrorDocument 402 http://192.168.12.242/subscription_info.html
#

#
# MaxRanges: Maximum number of Ranges in a request before
# returning the entire resource, or 0 for unlimited
# Default setting is to accept 200 Ranges
#MaxRanges 0

#
# EnableMMAP and EnableSendfile: On systems that support it,
# memory-mapping or the sendfile syscall is used to deliver
# files.  This usually improves server performance, but must
# be turned off when serving from networked-mounted
# filesystems or if support for these functions is otherwise
# broken on your system.
#
#EnableMMAP off
#EnableSendfile off

# Supplemental configuration
#
# The configuration files in the conf/extra/ directory can be
# included to add extra features or to modify the default configuration of
# the server, or you may simply copy their contents here and change as
# necessary.

# Server-pool management (MPM specific)修改鏈接數
Include conf/extra/httpd-mpm.conf

# Multi-language error messages
#Include conf/extra/httpd-multilang-errordoc.conf

# Fancy directory listings
#Include conf/extra/httpd-autoindex.conf

# Language settings
#Include conf/extra/httpd-languages.conf

# User home directories
#Include conf/extra/httpd-userdir.conf

# Real-time info on requests and configuration
#Include conf/extra/httpd-info.conf

# Virtual hosts 虛擬主機 沒有域名不須要設置
#Include conf/extra/httpd-vhosts.conf

# Local access to the Apache HTTP Server Manual
#Include conf/extra/httpd-manual.conf

# Distributed authoring and versioning (WebDAV)
#Include conf/extra/httpd-dav.conf

# Various default settings
#Include conf/extra/httpd-default.conf

# Secure (SSL/TLS) connections
#Include conf/extra/httpd-ssl.conf
#
# Note: The following must must be present to support
#       starting without SSL on platforms with no /dev/random equivalent
#       but a statically compiled-in mod_ssl.
#
<IfModule ssl_module>
SSLRandomSeed startup builtin
SSLRandomSeed connect builtin
</IfModule>

第三部分：mod_jk代碼講解

mod_jk 分析
1 mod_jk模塊的整體功能
因爲tomcat的HTTP處理部分都由Java所寫（5.5.12版本之後出現了native庫，用以
提升其I/O和SSL的性能[1]），在高併發的狀況下負載較高。而apache對於靜態文件的處
理能力比tomcat強，因此tomcat開發組開發了與apache結合使用的mod_jk模塊。該協議
由apache做請求代理，將HTTP協議的請求轉化爲AJP協議包，並傳給後端的
tomcat。mod_jk和apache如今廣泛使用AJP1.3協議[2]。它是一個二進制格式的協議，比
字符格式的HTTP協議解析速度要快。
除了性能的提高，mod_jk另外的一個做用能夠實現apache與tomcat一對多的對應，
使後端tomcat負載均衡。mod_jk也提供apache與tomcat連接狀況的監控。
mod_jk模塊的典型工做流程是這樣的：一個HTTP請求過來，mod_jk模塊根據其URI選
擇合適的worker來進行處理。若是是lb_worker（負載均衡的worker），就再根據各類條
件選擇後臺合適的ajp_worker（處理AJP協議的worker）。ajp_worker將HTTP協議的包，
組裝成AJP協議格式的包，而後選取一條空閒的連接，發送給後臺的tomcat服務器。等到
後臺將數據發送過來時，接收並解析AJP協議，從新組裝成HTTP協議，而後把結果發送給
客戶端。
2 mod_jk模塊的框架
2.1 線程
從宏觀上來說，mod_jk由一個watchdog線程和一組worker線程(進程)組成。
watchdog線程是在apache內部新建立的線程，它是一個維護線程。每隔
JkWatchdogInterval的時間（固然，全部worker線程也有一個統一的worker.maintain 時
間，JkWatchdogInterval應該至少大於worker.maintain），它會掃描全部worker線程。
watchdog線程會檢查每一個worker線程的空閒連接、負載狀況、與後端的連接狀況，並使共
享內存同步。worker線程是就是一些ajp13，ajp14，jni，lb或status類型的線程，負責
全部實際的工做。
在mod_jk中，線程內（外）的同步均是經過線程鎖（pthread_mutex_lock）來實現的。
而進程之間的全局同步，是用文件記錄鎖（flock或fcntl）來實現。進程間的數據共享是
用這樣作的：進程啓動時，建立一個JkShmSize 大小的文件，而後mmap到內存，因爲各進
程mmap到內存的是相同的鏡像，因此能夠實現數據的共享，可是寫入共享內存時，要作好
互斥。
因爲apache的基本處理方式（prefork和worker模式）就是一個線程/進程負責一個
鏈接，因此mod_jk各線程中對於網絡IO處理都是阻塞的。
2.2 worker對象
從具體的worker對象的角度來說，mod_jk由ajp_worker、jni_worker、lb_worker和
status_worker組成。這些對象參考了設計模式中factory的模型。每類worker都有生產
workers的factory。
在mod_jk中，其中的worker主要在worker.list中列出。其中，lb_worker能夠含有
balance_workers，以lb_sub_worker的形式存儲於lb_worker中。lb_sub_worker能夠是各
種類型的ajp_worker。因此真正工做的ajp_worker既能夠「單幹」，也能夠由lb_worker
來分配任務。這主要取決於URI到底映射到哪一個worker上以及該worker是否在
worker.list配置。
lb_worker，lb_sub_worker和ajp_worker一些配置信息都位於其結構體中，而狀態信
息或在運行中可變的參數則位於共享內存中的對應結構體中，固然也並不絕對，有些參數是
冗餘的。
從正在運行的某個線程的角度上來說，ajp_worker就是對應了一個線程。
3 從HTTP到AJP的處理流程
因爲mod_jk模塊是apache的處理模塊，本節主要是講述mod_jk模塊從客戶端到後端
服務器的處理流程。中間會涉及一些apache模塊的一些結構。
3.1 mod_jk模塊在apache中的定義
3.1.1 mod_jk定義
/* 這是jk模塊的主要定義結構體*/
module AP_MODULE_DECLARE_DATA jk_module = {
STANDARD20_MODULE_STUFF,
NULL, /* dir config creater */
NULL, /* dir merger --- default is to override */
create_jk_config, /*建立 jk模塊的配置結構體*/
merge_jk_config, /* 初始化及合併 jk模塊的配置結構體*/
jk_cmds, /* 全部在apahce中的命令及操做函數 */
jk_register_hooks /* 具體的操做函數處理鉤子 */
};
3.1.2 mod_jk模塊的主要處理函數
/* mod_jk將各處理函數掛到相應的鉤子上，鉤子實際上就是一些函數指針。針對某個HTTP
請求，這些函數會自上而下執行。*/
static void jk_register_hooks(apr_pool_t * p)
{
/* 該函數在apache讀入配置後運行，用以初始化全局互斥鎖，jk日誌，全局變量的初
始化，以及讀入 workers.properties、uriworkermap.properties文件，初始化各worker
的屬性，創建worker名稱到worker結構體的映射，uri到worker的映射*/
ap_hook_post_config(jk_post_config, NULL, NULL, APR_HOOK_MIDDLE);
/*該函數在apache主進程fork工做子進程後作的初始化工做，主要包括初始化進程內
互斥鎖，開啓維護線程，讀入共享內存*/
ap_hook_child_init(jk_child_init, NULL, NULL, APR_HOOK_MIDDLE);
/* 將mod_jk的URI到真實URI，而後URI到worker的映射翻譯過程，用以找到該URI
相應的worker_name */
ap_hook_translate_name(jk_translate, NULL, NULL, APR_HOOK_MIDDLE);
#if (MODULE_MAGIC_NUMBER_MAJOR > 20010808)
/* 綁定那些alias_dir的URI到mod_jk的配置，並找到相應worker_name */
ap_hook_map_to_storage(jk_map_to_storage, NULL, NULL, APR_HOOK_MIDDLE);
/* 這是mod_jk的主要處理函數 */
ap_hook_handler(jk_handler, NULL, NULL, APR_HOOK_MIDDLE);
#endif
}
3.2 jk_handler函數
jk_handler函數是mod_jk的主要處理函數，它負責將HTTP請求從apache發到tomcat,
再從tomcat接受數據，並返回給客戶。
它的處理過程以下：
1. 根據前面獲得的worker_name，找到相應的jk_worker（其結構體見4.4）。
2. 初始化服務結構體jk_ws_service，主要是針對HTTP服務端的一些設置及函數（服務
的結構體見4.5），與AJP協議關係不大。
3. 調用jk_worker的get_endpoint函數，獲取具體的jk_endpoint結構體（函數見
3.3.1和3.4.1，jk_endpoint的結構體定義見4.4）。
4. 調用上述jk_endpoint的service函數。
5. 調用上述jk_endpoint的done函數，結束與tomcat的AJP鏈接。
6. 根據函數的結果處理各類狀態。
7. 釋放資源。
3.3 lb_worker的處理函數
3.3.1 lb_worker的get_endpoint
初始化lb_worker的endpoint結構體，掛上其service及done函數。
3.3.2 lb_worker的service函數
它的處理過程以下：
1. 獲取共享內存中記錄的worker狀態。
2. 若是須要綁定sessionID，獲取sessionID。
3. 調用get_most_suitable_worker函數，獲取相應的lb_sub_worker(也即
ajp_worker)。
4. 調用ajp_worker的get_endpoint函數。
5. 調用上述endpoint的service函數。
6. 調用上述endpoint的done函數。
7. 根據service的返回結果，更新各類記錄狀態。
3.3.3 get_most_suitable_worker函數
它的處理過程以下：
1. 若是須要綁定sessionID，就根據sessionID找到工做正常的最佳worker。
2. 若是找不到，則調用find_best_worker函數。其處理過程以下：
i. 又調用find_best_byvalue函數。其處理過程以下：按照Round Robin的方式在
本lb_worker中找到第一個不在錯誤狀態、也沒有中止、沒有disabled 、也不
busy的lb_sub_worker。
ii.若是find_best_byvalue返回錯誤，說明本lb_worker的lb_sub_worker都處於
非正常工做狀態，須要調用find_failover_worker函數，經過
redirect、route、domain指令來進行查找[3]。
3.4 ajp_worker的處理函數
3.4.1 ajp_worker的get_endpoint函數
它的主要功能是：找到與後端tomcat的一個空閒鏈接。
3.4.2 ajp_worker的ajp_service函數
該函數主要分爲 ajp_send_request和and ajp_get_reply兩個函數。
它的處理過程以下：
1. 獲取共享內存中的狀態。
2. 分配AJP請求包、恢復包、POST包的內存。
3. 調用ajp_marshal_into_msgb函數，將HTTP請求包轉化爲AJP包。
4. 將當前ajp_worker的狀態更新。
5. 調用ajp_send_request函數。
6. 若是發送成功，調用ajp_get_reply函數，等待並接受AJP包。
7. 若是成功，更新當前狀態。
3.4.2 ajp_worker的ajp_send_request函數
它的處理過程以下：
1. 調用jk_is_socket_connected函數，檢查即將發送的socket是否有效。它的檢查過
程是運用select函數，等1微妙，若是成功返回說明，該socket的文件描述符至少
在內核中還有效。
2. 若是上一次發送超時，則調用ajp_handle_cping_cpong函數來判斷後端鏈接是否有
效。該函數主要是發出了一個AJP13_CPING_REQUEST類型的AJP包，若是tomcat收
到，應返回一個AJP13_CPONG_REPLY的包。
3. 若是上述的測試都成功，調用ajp_connection_tcp_send_message，發送AJP包。
3.4.3 ajp_worker的ajp_get_reply函數
它的處理過程以下：
1. 調用jk_is_input_event，用select等待接受數據，直到socket有接受數據。
2. 調用ajp_connection_tcp_get_message，接受AJP包，並檢查協議頭。
3. 調用ajp_process_callback，對該AJP包進行解析處理。其處理過程以下：
i. 若是是JK_AJP13_SEND_HEADERS包，將其解包成HTTP包頭。若是沒有錯誤，就調
用jk_ws_service->start_response（）函數發送HTTP回覆的head。返回
JK_AJP13_SEND_HEADERS。
ii.若是是JK_AJP13_SEND_BODY_CHUNK包，調用jk_ws_service->write發送HTTP回
復的body。返回JK_AJP13_NO_RESPONSE。
iii.若是是JK_AJP13_GET_BODY_CHUNK包，說明還有數據要發送到tomcat，調用
ajp_read_into_msg_buff，繼續發送數據。返回JK_AJP13_HAS_RESPONSE。
iv.若是是JK_AJP13_END_RESPONSE包，就說明tomcat的回覆已經完成。返回
JK_AJP13_END_RESPONSE。
3.5 jk_ws_service的一些處理函數
3.5.1 jk_ws_service 的 ws_start_response函數
該函數主要是構建HTTP回覆包的頭部。
3.5.2 jk_ws_service 的 ws_write函數
調用 apache的ap_rwrite函數，發送整個HTTP包。
3.5.3 jk_ws_service 的 ws_read函數
調用apache的ap_get_client_block讀入所有的request body數據。
4 mod_jk的主要數據結構
4.1 lb_worker
lb_worker是負載均衡worker。主要負責調配其名下的一些lb_sub_worker 。

dist/common/jk_lb_worker.h
struct lb_worker
{
/* jk模塊通用worker結構體。包含一些回調函數，不一樣的worker有不一樣的函數實現
*/
jk_worker_t worker;
/* Shared memory worker data */
jk_shm_lb_worker_t *s;
char name[JK_SHM_STR_SIZ+1];
/* Sequence counter starting at 0 and increasing
* every time we change the config
*/
volatile unsigned int sequence;
jk_pool_t p;
jk_pool_atom_t buf[TINY_POOL_SIZE];
JK_CRIT_SEC cs;
/*其名下的workers*/
lb_sub_worker_t *lb_workers;
unsigned int num_of_workers;
int sticky_session;
int sticky_session_force;
int recover_wait_time;
int max_reply_timeouts;
int retries;
int retry_interval;
int lbmethod;
int lblock;
int maintain_time;
unsigned int max_packet_size;
unsigned int next_offset;
/* Session cookie */
char session_cookie[JK_SHM_STR_SIZ+1];
/* Session path */
char session_path[JK_SHM_STR_SIZ+1];
};
lb_sub_worker是由lb_worker支配的ajp_worker。固然lb_sub_worker有不一樣的類型。
它們的實際類型存儲在ajp_worker中。
dist/common/jk_lb_worker.h
struct lb_sub_worker
{
/* 包含ajp_worker的回調函數及其ajp_worker結構體*/
jk_worker_t *worker;
/* Shared memory worker data */
jk_shm_lb_sub_worker_t *s;
char name[JK_SHM_STR_SIZ+1];
/* Sequence counter starting at 0 and increasing
* every time we change the config
*/
volatile unsigned int sequence;
/* route */
char route[JK_SHM_STR_SIZ+1];
/* worker domain */
char domain[JK_SHM_STR_SIZ+1];
/* worker redirect route */
char redirect[JK_SHM_STR_SIZ+1];
/* worker distance */
int distance;
/* current activation state (config) of the worker */
int activation;
/* Current lb factor */
int lb_factor;
/* Current worker index */
int i;
/* Current lb reciprocal factor */
jk_uint64_t lb_mult;
};
typedef struct lb_sub_worker lb_sub_worker_t;
4.2 ajp_worker
ajp_worker是具體工做的worker，對應後端一個tomcat應用服務。
dist/common/jk_ajp_common.c
struct ajp_worker
{
/* 包含ajp_worker的回調函數*/
jk_worker_t worker;
/* Shared memory worker data */
jk_shm_ajp_worker_t *s;
char name[JK_SHM_STR_SIZ+1];
/* Sequence counter starting at 0 and increasing
* every time we change the config
*/
volatile unsigned int sequence;
jk_pool_t p;
jk_pool_atom_t buf[TINY_POOL_SIZE];
JK_CRIT_SEC cs;
struct sockaddr_in worker_inet_addr; /* Contains host and port */
unsigned connect_retry_attempts;
const char *host;
int port;
int maintain_time;
/*
* Open connections cache...
*
* 1. Critical section object to protect the cache.
* 2. Cache size.
* 3. An array of "open" endpoints.
*/
unsigned int ep_cache_sz;
unsigned int ep_mincache_sz;
unsigned int ep_maxcache_sz;
int cache_acquire_timeout;
ajp_endpoint_t **ep_cache;
int proto; /* PROTOCOL USED AJP13/AJP14 */
jk_login_service_t *login;
/* Weak secret similar with ajp12, used in ajp13 */
const char *secret;
/*
* Post physical connect handler.
* AJP14 will set here its login handler
*/
int (*logon) (ajp_endpoint_t * ae, jk_logger_t *l);
/*
* Handle Socket Timeouts
*/
int socket_timeout;
int socket_connect_timeout;
int keepalive;
int socket_buf;
/*
* Handle Cache Timeouts
*/
int cache_timeout;
/*
* Handle Connection/Reply Timeouts
*/
int connect_timeout; /* connect cping/cpong delay in ms (0 means
disabled) */
int reply_timeout; /* reply timeout delay in ms (0 means disabled) */
int prepost_timeout; /* before sending a request cping/cpong timeout
delay in ms (0 means disabled) */
int conn_ping_interval; /* interval for sending keepalive cping packets on
* unused connection */
int ping_timeout; /* generic cping/cpong timeout. Used for keepalive
packets or
* as default for boolean valued connect and
prepost timeouts.
*/
unsigned int ping_mode; /* Ping mode flags (which types of cpings should
be used) */
/*
* Recovery options
*/
unsigned int recovery_opts;
/*
* Public property to enable the number of retry attempts
* on this worker.
*/
int retries;
unsigned int max_packet_size; /* Maximum AJP Packet size */
int retry_interval; /* Number of milliseconds to sleep before
doing a retry */
/*
* HTTP status that will cause failover (0 means disabled)
*/
unsigned int http_status_fail_num;
int http_status_fail[JK_MAX_HTTP_STATUS_FAILS];
};
4.3 status_worker
status_worker用於產生一些狀態的統計信息。
dist/common/jk_statuc.c
struct status_worker
{
jk_pool_t p;
jk_pool_atom_t buf[TINY_POOL_SIZE];
const char *name;
const char *css;
const char *ns;
const char *xmlns;
const char *doctype;
const char *prefix;
int read_only;
char **user_names;
unsigned int num_of_users;
int user_case_insensitive;
jk_uint32_t good_mask;
jk_uint32_t bad_mask;
jk_worker_t worker;
jk_worker_env_t *we;
};
4.4 jk_worker和 jk_endpoint
jk_worker是全部worker通用結構體名稱, 主要包含的是一些函數指針。它是一個類
似java中抽象類的概念，各成員函數在從factory函數生產時初始化。
dist/common/jk_service.h
struct jk_worker
{
/*
* A 'this' pointer which is used by the subclasses of this class to
* point to data/functions which are specific to a given protocol
* (e.g. ajp12 or ajp13 or ajp14).
*/
void *worker_private;/* 指向ajp_worker，lb_worker結構體 ...*/
int type;
/*
* For all of the below (except destroy), the first argument is
* essentially a 'this' pointer.
*/
/* 先於init函數調用，用於分配各種worker結構體的內存，做必要的初始化
* Given a worker which is in the process of being created, and a list
* of configuration options (or 'properties'), check to see if it the
* options are. This will always be called before the init() method.
* The init/validate distinction is a bit hazy to me.
* See jk_ajp13_worker.c/jk_ajp14_worker.c and jk_worker.c-
>wc_create_worker()
*/
int (JK_METHOD * validate) (jk_worker_t *w,
jk_map_t *props,
jk_worker_env_t *we, jk_logger_t *l);
/*
* Update worker either from jk_status or reloading from workers.properties
*/
int (JK_METHOD * update) (jk_worker_t *w,
jk_map_t *props,
jk_worker_env_t *we, jk_logger_t *l);
/*
* Do whatever initialization needs to be done to start this worker up.
* Configuration options are passed in via the props parameter.
*/
int (JK_METHOD * init) (jk_worker_t *w,
jk_map_t *props,
jk_worker_env_t *we, jk_logger_t *l);
/*
* Obtain an endpoint to service a particular request. A pointer to
* the endpoint is stored in pend.
*/
int (JK_METHOD * get_endpoint) (jk_worker_t *w,
jk_endpoint_t **pend, jk_logger_t *l);
/*
* Shutdown this worker. The first argument is not a 'this' pointer,
* but rather a pointer to 'this', so that the object can be free'd (I
* think -- though that doesn't seem to be happening. Hmmm).
*/
int (JK_METHOD * destroy) (jk_worker_t **w, jk_logger_t *l);
/*
* Maintain this worker.
*/
int (JK_METHOD * maintain) (jk_worker_t *w, time_t now, jk_logger_t *l);
};
/* jk_endpoint能夠稱之爲通用終端服務結構體，各種worker可能有本身的endpoint結構
體。好比ajp_worker, 該終端是用來作具體工做的，好比發出請求，接收AJP數據等等。如
果是lb_worker，該終端是的做用是找出合適ajp_worker, 把任務交給它。* /
struct jk_endpoint
{
jk_uint64_t rd;
jk_uint64_t wr;
/*
* Flag to pass back recoverability status from
* a load balancer member to the load balancer itself.
* Depending on the configuration and request status
* recovery is not allowed.
*/
int recoverable;
/*
* A 'this' pointer which is used by the subclasses of this class to
* point to data/functions which are specific to a given protocol
* (e.g. ajp12 or ajp13 or ajp14).
*/
void *endpoint_private;
/* 該函數是具體的服務函數
* Forward a request to the servlet engine. The request is described
* by the jk_ws_service_t object.
* is_error is either 0 meaning recoverable or set to
* the HTTP error code.
*/
int (JK_METHOD * service) (jk_endpoint_t *e,
jk_ws_service_t *s,
jk_logger_t *l, int *is_error);
/*
* Called when this particular endpoint has finished processing a
* request. For some protocols (e.g. ajp12), this frees the memory
* associated with the endpoint. For others (e.g. ajp13/ajp14), this can
* return the endpoint to a cache of already opened endpoints.
*
* Note that the first argument is *not* a 'this' pointer, but is
* rather a pointer to a 'this' pointer. This is necessary, because
* we may need to free this object.
*/
int (JK_METHOD * done) (jk_endpoint_t **p, jk_logger_t *l);
};
4.5 jk_ws_service
該結構體是與apache相關的一些參數或函數，面向HTTP協議，與AJP協議不太相關。
dist/common/jk_service.h
struct jk_ws_service
{
/*
* A 'this' pointer which is used by the subclasses of this class to
* point to data which is specific to a given web server platform
* (e.g. Apache or IIS).
*/
void *ws_private;
/*
* Provides memory management. All data specific to this request is
* allocated within this pool, which can then be reclaimed at the end
* of the request handling cycle.
*
* Alive as long as the request is alive.
*/
jk_pool_t *pool;
/*
* CGI Environment needed by servlets
*/
const char *method;
const char *protocol;
char *req_uri;
const char *remote_addr;
const char *remote_host;
const char *remote_user;
const char *auth_type;
const char *query_string;
const char *server_name;
unsigned server_port;
char *server_software;
jk_uint64_t content_length; /* 64 bit integer that represents the content */
/* length should be 0 if unknown. */
unsigned is_chunked; /* 1 if content length is unknown (chunked rq) */
unsigned no_more_chunks; /* 1 if last chunk has been read */
jk_uint64_t content_read; /* number of bytes read */
/*
* SSL information
*
* is_ssl - True if request is in ssl connection
* ssl_cert - If available, base64 ASN.1 encoded client certificates.
* ssl_cert_len - Length of ssl_cert, 0 if certificates are not available.
* ssl_cipher - The ssl cipher suite in use.
* ssl_session - The ssl session string
*
* In some servers it is impossible to extract all this information, in this
* case, we are passing NULL.
*/
int is_ssl;
char *ssl_cert;
unsigned ssl_cert_len;
char *ssl_cipher;
char *ssl_session;
/*
* SSL extra information for Servlet 2.3 API
*
* ssl_key_size - ssl key size in use
*/
int ssl_key_size;
/*
* Headers, names and values.
*/
char **headers_names; /* Names of the request headers */
char **headers_values; /* Values of the request headers */
unsigned num_headers; /* Number of request headers */
/*
* Request attributes.
*
* These attributes that were extracted from the web server and are
* sent to Tomcat.
*
* The developer should be able to read them from the ServletRequest
* attributes. Tomcat is required to append org.apache.tomcat. to
* these attribute names.
*/
char **attributes_names; /* Names of the request attributes */
char **attributes_values; /* Values of the request attributes */
unsigned num_attributes; /* Number of request attributes */
/*
* The route is in use when the adapter load balance among
* several workers. It is the ID of a specific target in the load balance
* group. We are using this variable to implement target session
* affinity
*/
const char *route;
/* Temp solution for auth. For native1 it'll be sent on each request,
if an option is present. For native2 it'll be sent with the first
request. On java side, both cases will work. For tomcat3.2 or
a version that doesn't support secret - don't set the secret,
and it'll work.
*/
const char *secret;
/*
* Area to get POST data for fail-over recovery in POST
*/
jk_msg_buf_t *reco_buf;
int reco_status;
/*
* If set call flush after each write
*/
int flush_packets;
/*
* If set call flush after AJP13_SEND_HEADERS.
*/
int flush_header;
/*
* service extensions
*/
svc_extension_t extension;
/*
* JK_TRUE if response headers have been sent back
*/
int response_started;
/*
* JK_TRUE if response should not be send to the client
*/
int response_blocked;
/*
* HTTP status sent from container.
*/
int http_response_status;
/* Uri worker map. Added for virtual host support
*/
jk_uri_worker_map_t *uw_map;
/* 下面這些回調函數實現均可以在mod_jk.c找到
* Callbacks into the web server. For each, the first argument is
* essentially a 'this' pointer. All return JK_TRUE on success
* and JK_FALSE on failure.
*/
/*
* Send the response headers to the browser.
*/
int (JK_METHOD * start_response) (jk_ws_service_t *s,
int status,
const char *reason,
const char *const *header_names,
const char *const *header_values,
unsigned num_of_headers);
/*
* Read a chunk of the request body into a buffer. Attempt to read len
* bytes into the buffer. Write the number of bytes actually read into
* actually_read.
*/
int (JK_METHOD * read) (jk_ws_service_t *s,
void *buffer,
unsigned len, unsigned *actually_read);
/*
* Write a chunk of response data back to the browser.
*/
int (JK_METHOD * write) (jk_ws_service_t *s,
const void *buffer, unsigned len);
/*
* Flush a chunk of response data back to the browser.
*/
void (JK_METHOD * flush) (jk_ws_service_t *s);
/*
* Done with sending response back to the browser.
*/
void (JK_METHOD * done) (jk_ws_service_t *s);
/*
* If set do not reuse socket after each full response
*/
int disable_reuse;
/*
* Add more data to log facilities.
*/
void (JK_METHOD * add_log_items) (jk_ws_service_t *s,
const char *const *log_names,
const char *const *log_values,
unsigned num_of_items);
/*
* Iterate through all vhosts
*/
void *(JK_METHOD * next_vhost) (void *d);
/*
* String representation of a vhost
*/
void (JK_METHOD * vhost_to_text) (void *d, char *buf, size_t len);
/*
* Get uw_map associated with a vhost
*/
jk_uri_worker_map_t *(JK_METHOD * vhost_to_uw_map) (void *d);
};

4.6 共享內存中一些數據結構
共享內存中的數據結構基本上都是記錄之用。有些參數在運行中會實時變化。

dist/common/jk_shm.h
/** jk shm generic worker record structure */
struct jk_shm_worker_header
{
int id;
int type;
/* worker name */
char name[JK_SHM_STR_SIZ+1];
/* Sequence counter starting at 0 and increasing
* every time we change the config
*/
volatile unsigned int sequence;
};
typedef struct jk_shm_worker_header jk_shm_worker_header_t;
/** jk shm ajp13/ajp14 worker record structure */
struct jk_shm_ajp_worker
{
jk_shm_worker_header_t h;
/* Configuration data mirrored from ajp_worker */
int cache_timeout;
int connect_timeout;
int reply_timeout;
int prepost_timeout;
unsigned int recovery_opts;
int retries;
int retry_interval;
unsigned int max_packet_size;
/* current error state (runtime) of the worker */
volatile int state;
/* Statistical data */
/* Number of currently busy channels */
volatile int busy;
/* Maximum number of busy channels
該參數並不是咱們的maxbusy，它是該worker自程序運行以來busy的最大值 */
volatile int max_busy;
volatile time_t error_time;
/* Number of bytes read from remote */
volatile jk_uint64_t readed;
/* Number of bytes transferred to remote */
volatile jk_uint64_t transferred;
/* Number of times the worker was used */
volatile jk_uint64_t used;
/* Number of times the worker was used - snapshot during maintenance */
volatile jk_uint64_t used_snapshot;
/* Number of non 200 responses */
volatile jk_uint32_t errors;
/* Decayed number of reply_timeout errors */
volatile jk_uint32_t reply_timeouts;
/* Number of client errors */
volatile jk_uint32_t client_errors;
/* Last reset time */
volatile time_t last_reset;
volatile time_t last_maintain_time;
};
typedef struct jk_shm_ajp_worker jk_shm_ajp_worker_t;
/** jk shm lb sub worker record structure */
struct jk_shm_lb_sub_worker
{
jk_shm_worker_header_t h;
/* route */
char route[JK_SHM_STR_SIZ+1];
/* worker domain */
char domain[JK_SHM_STR_SIZ+1];
/* worker redirect route */
char redirect[JK_SHM_STR_SIZ+1];
/* Number of currently busy channels */
volatile int busy;
/* worker distance */
volatile int distance;
/* current activation state (config) of the worker */
volatile int activation;
/* current error state (runtime) of the worker */
volatile int state;
/* Current lb factor */
volatile int lb_factor;
/* 咱們的參數加在這裏*/
volatile int maxbusy;
/* Current lb reciprocal factor */
volatile jk_uint64_t lb_mult;
/* Current lb value */
volatile jk_uint64_t lb_value;
/* Statistical data */
volatile time_t error_time;
/* Number of times the worker was elected - snapshot during maintenance */
volatile jk_uint64_t elected_snapshot;
/* Number of non 200 responses */
volatile jk_uint32_t errors;
};
typedef struct jk_shm_lb_sub_worker jk_shm_lb_sub_worker_t;
/** jk shm lb worker record structure */
struct jk_shm_lb_worker
{
jk_shm_worker_header_t h;
/* Number of currently busy channels，該值是其名下ajp_worker的busy值之和*/
volatile int busy;
/* Maximum number of busy channels，該值是其名下ajp_worker的max_busy值之和
*/
volatile int max_busy;
int sticky_session;
int sticky_session_force;
int recover_wait_time;
int max_reply_timeouts;
int retries;
int retry_interval;
int lbmethod;
int lblock;
unsigned int max_packet_size;
/* Last reset time */
volatile time_t last_reset;
volatile time_t last_maintain_time;
/* Session cookie */
char session_cookie[JK_SHM_STR_SIZ+1];
/* Session path */
char session_path[JK_SHM_STR_SIZ+1];
};
typedef struct jk_shm_lb_worker jk_shm_lb_worker_t;