Nameserver版本

转载

mob6454cc66e0d5 2024-07-15 07:56:10

文章标签 Nameserver版本 RocketMQ JAVA java apache 文章分类 架构后端开发

添加了注释的源码
https://github.com/WangTingYeYe/rocketmq_source

先来一张总体的源码流程：

Nameserver版本_java

前提

请大家先浏览我前面转载的官网的一些rocketmq的基本概念和架构设计之后再阅读本文。

Nameserver版本_RocketMQ_02

NameServer 是什么

官网解释：
NameServer 充当路由消息的提供者。生产者或消费者能够通过名字服务查找各主题相应的Broker IP列表。多个Namesrv实例组成集群，但相互独立，没有信息交换。
白话文：
生产者和消费者怎么知道每个broker的地址以及broker上消息分别存放在集群中的那台机器上？
NameServer就是为了解决这个，可以理解为就是一个数据库。
NameServer集群之间的服务是没有任何的信息交互的

NameServer 启动流程

分析一个中间件的启动入口，第一步应该看他的启动脚本。

mqnamesrv

#!/bin/sh

# 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.

if [ -z "$ROCKETMQ_HOME" ] ; then
  ## resolve links - $0 may be a link to maven's home
  PRG="$0"

  # need this for relative symlinks
  while [ -h "$PRG" ] ; do
    ls=`ls -ld "$PRG"`
    link=`expr "$ls" : '.*-> \(.*\)$'`
    if expr "$link" : '/.*' > /dev/null; then
      PRG="$link"
    else
      PRG="`dirname "$PRG"`/$link"
    fi
  done

  saveddir=`pwd`

  ROCKETMQ_HOME=`dirname "$PRG"`/..

  # make it fully qualified
  ROCKETMQ_HOME=`cd "$ROCKETMQ_HOME" && pwd`

  cd "$saveddir"
fi

export ROCKETMQ_HOME

sh ${ROCKETMQ_HOME}/bin/runserver.sh org.apache.rocketmq.namesrv.NamesrvStartup $@

runserver.sh

#!/bin/sh

# 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.

#===========================================================================================
# Java Environment Setting
#===========================================================================================
error_exit ()
{
    echo "ERROR: $1 !!"
    exit 1
}

[ ! -e "$JAVA_HOME/bin/java" ] && JAVA_HOME=$HOME/jdk/java
[ ! -e "$JAVA_HOME/bin/java" ] && JAVA_HOME=/usr/java
[ ! -e "$JAVA_HOME/bin/java" ] && error_exit "Please set the JAVA_HOME variable in your environment, We need java(x64)!"

export JAVA_HOME
export JAVA="$JAVA_HOME/bin/java"
export BASE_DIR=$(dirname $0)/..
export CLASSPATH=.:${BASE_DIR}/conf:${BASE_DIR}/lib/*:${CLASSPATH}

#===========================================================================================
# JVM Configuration
#===========================================================================================
# The RAMDisk initializing size in MB on Darwin OS for gc-log
DIR_SIZE_IN_MB=600

choose_gc_log_directory()
{
    case "`uname`" in
        Darwin)
            if [ ! -d "/Volumes/RAMDisk" ]; then
                # create ram disk on Darwin systems as gc-log directory
                DEV=`hdiutil attach -nomount ram://$((2 * 1024 * DIR_SIZE_IN_MB))` > /dev/null
                diskutil eraseVolume HFS+ RAMDisk ${DEV} > /dev/null
                echo "Create RAMDisk /Volumes/RAMDisk for gc logging on Darwin OS."
            fi
            GC_LOG_DIR="/Volumes/RAMDisk"
        ;;
        *)
            # check if /dev/shm exists on other systems
            if [ -d "/dev/shm" ]; then
                GC_LOG_DIR="/dev/shm"
            else
                GC_LOG_DIR=${BASE_DIR}
            fi
        ;;
    esac
}

choose_gc_options()
{
    # Example of JAVA_MAJOR_VERSION value : '1', '9', '10', '11', ...
    # '1' means releases befor Java 9
    JAVA_MAJOR_VERSION=$("$JAVA" -version 2>&1 | sed -r -n 's/.* version "([0-9]*).*$/\1/p')
    if [ -z "$JAVA_MAJOR_VERSION" ] || [ "$JAVA_MAJOR_VERSION" -lt "9" ] ; then
      JAVA_OPT="${JAVA_OPT} -server -Xms4g -Xmx4g -Xmn2g -XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=320m"
      JAVA_OPT="${JAVA_OPT} -XX:+UseConcMarkSweepGC -XX:+UseCMSCompactAtFullCollection -XX:CMSInitiatingOccupancyFraction=70 -XX:+CMSParallelRemarkEnabled -XX:SoftRefLRUPolicyMSPerMB=0 -XX:+CMSClassUnloadingEnabled -XX:SurvivorRatio=8 -XX:-UseParNewGC"
      JAVA_OPT="${JAVA_OPT} -verbose:gc -Xloggc:${GC_LOG_DIR}/rmq_srv_gc_%p_%t.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps"
      JAVA_OPT="${JAVA_OPT} -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=30m"
    else
      JAVA_OPT="${JAVA_OPT} -server -Xms4g -Xmx4g -XX:MetaspaceSize=128m -XX:MaxMetaspaceSize=320m"
      JAVA_OPT="${JAVA_OPT} -XX:+UseG1GC -XX:G1HeapRegionSize=16m -XX:G1ReservePercent=25 -XX:InitiatingHeapOccupancyPercent=30 -XX:SoftRefLRUPolicyMSPerMB=0"
      JAVA_OPT="${JAVA_OPT} -Xlog:gc*:file=${GC_LOG_DIR}/rmq_srv_gc_%p_%t.log:time,tags:filecount=5,filesize=30M"
    fi
}

choose_gc_log_directory
choose_gc_options
JAVA_OPT="${JAVA_OPT} -XX:-OmitStackTraceInFastThrow"
JAVA_OPT="${JAVA_OPT} -XX:-UseLargePages"
#JAVA_OPT="${JAVA_OPT} -Xdebug -Xrunjdwp:transport=dt_socket,address=9555,server=y,suspend=n"
JAVA_OPT="${JAVA_OPT} ${JAVA_OPT_EXT}"
JAVA_OPT="${JAVA_OPT} -cp ${CLASSPATH}"

$JAVA ${JAVA_OPT} $@

可以看到最后就是执行了
java org.apache.rocketmq.namesrv.NamesrvStartup