Hyperledger Fabric开发之启动CouchDB作为状态数据库

测试环境

• Mac Catalina
• Docker Desktop 3.6.0
• Hyperledger Fabric 2.5.4
• CouchDB 3.3.2

简单分析

当前版本的Fabric 2.5.4默认支持的LevelDB仅能够实现存储简单的键值对数据，并且LevelDB与Peer节点并存于同一个操作系统进程中。

CouchDB适用于存储JSON文件，并支持富查询和对更多数据类型的操作。但是，CouchDB进程与Peer节点进程是独立存在的，每个Peer节点进程都对应一个CouchDB进程。

因此，在本文中要使用CouchDB来替换LevelDB用作状态数据库，需要把它独立运行并进行手动配置。

幸运的是，Fabric的测试网络已经为我们作好了配置。接下来，我们把相关配置项分析一下。

重要声明：

当前下载安装的Hyperledger Fabric 2.5.4正好其生成测试配置网络时对应最新版本正式发行的CouchDB 3.3.2。我们注意到，我们独立下载安装的CouchDB 3.3.2正好与这里配置对应，不再需要修改。

1、Docker Compose中配置CouchDB服务

对应文件位于测试网络的路径位置是：test-network/compose，文件为：compose-couch.yaml。

内容如下：

# Copyright IBM Corp. All Rights Reserved.
#
# SPDX-License-Identifier: Apache-2.0
#

version: '3.7'

networks:
  test:
    name: fabric_test

services:
  couchdb0:
    container_name: couchdb0
    image: couchdb:3.3.2
    labels:
      service: hyperledger-fabric
    # Populate the COUCHDB_USER and COUCHDB_PASSWORD to set an admin user and password
    # for CouchDB.  This will prevent CouchDB from operating in an "Admin Party" mode.
    environment:
      - COUCHDB_USER=admin
      - COUCHDB_PASSWORD=adminpw
    # Comment/Uncomment the port mapping if you want to hide/expose the CouchDB service,
    # for example map it to utilize Fauxton User Interface in dev environments.
    ports:
      - "5984:5984"
    networks:
      - test
  peer0.org1.example.com:
    environment:
      - CORE_LEDGER_STATE_STATEDATABASE=CouchDB
      - CORE_LEDGER_STATE_COUCHDBCONFIG_COUCHDBADDRESS=couchdb0:5984
      # The CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME and CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD
      # provide the credentials for ledger to connect to CouchDB.  The username and password must
      # match the username and password set for the associated CouchDB.
      - CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME=admin
      - CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD=adminpw
    depends_on:
      - couchdb0

  couchdb1:
    container_name: couchdb1
    image: couchdb:3.3.2
    labels:
      service: hyperledger-fabric
    # Populate the COUCHDB_USER and COUCHDB_PASSWORD to set an admin user and password
    # for CouchDB.  This will prevent CouchDB from operating in an "Admin Party" mode.
    environment:
      - COUCHDB_USER=admin
      - COUCHDB_PASSWORD=adminpw
    # Comment/Uncomment the port mapping if you want to hide/expose the CouchDB service,
    # for example map it to utilize Fauxton User Interface in dev environments.
    ports:
      - "7984:5984"
    networks:
      - test
  peer0.org2.example.com:
    environment:
      - CORE_LEDGER_STATE_STATEDATABASE=CouchDB
      - CORE_LEDGER_STATE_COUCHDBCONFIG_COUCHDBADDRESS=couchdb1:5984
      # The CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME and CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD
      # provide the credentials for ledger to connect to CouchDB.  The username and password must
      # match the username and password set for the associated CouchDB.
      - CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME=admin
      - CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD=adminpw
    depends_on:
      - couchdb1

注意上述默认配置中CouchDB用户名与密码及端口号（5984）。

2、在Peer服务中配置使用了CouchDB

另外，注意到上面配置默认定义了2个Peer服务。这两个服务分别为组织Org1和Org2定义了Peer节点运行的Docker容器。例如，peer0.org1.example.com的定义代码如下：

peer0.org1.example.com:
    environment:
      - CORE_LEDGER_STATE_STATEDATABASE=CouchDB
      - CORE_LEDGER_STATE_COUCHDBCONFIG_COUCHDBADDRESS=couchdb0:5984
      # The CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME and CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD
      # provide the credentials for ledger to connect to CouchDB.  The username and password must
      # match the username and password set for the associated CouchDB.
      - CORE_LEDGER_STATE_COUCHDBCONFIG_USERNAME=admin
      - CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD=adminpw
    depends_on:
      - couchdb0

下面，我们将以CouchDB选项启动Fabric测试网络。当然，首先要启动Docker。

第一步：启动Docker Desktop

第二步：以CouchDB选项启动Fabric测试网络

1. 使用cd命令进入到test-network目录下
2. 运行下列命令：

./network.sh up -s couchdb

在文件network.sh中有一个函数networkUp()，用于启动测试网络。

# Bring up the peer and orderer nodes using docker compose.
function networkUp() {
  checkPrereqs

  # generate artifacts if they don't exist
  if [ ! -d "organizations/peerOrganizations" ]; then
    createOrgs
  fi

  COMPOSE_FILES="-f compose/${COMPOSE_FILE_BASE} -f compose/${CONTAINER_CLI}/${CONTAINER_CLI}-${COMPOSE_FILE_BASE}"

  if [ "${DATABASE}" == "couchdb" ]; then
    COMPOSE_FILES="${COMPOSE_FILES} -f compose/${COMPOSE_FILE_COUCH} -f compose/${CONTAINER_CLI}/${CONTAINER_CLI}-${COMPOSE_FILE_COUCH}"
  fi

  DOCKER_SOCK="${DOCKER_SOCK}" ${CONTAINER_CLI_COMPOSE} ${COMPOSE_FILES} up -d 2>&1

  $CONTAINER_CLI ps -a
  if [ $? -ne 0 ]; then
    fatalln "Unable to start network"
  fi
}

只需要注意其中的几个变量定义：COMPOSE_FILE_BASE和COMPOSE_FILE_COUCH。

接下来，我们启动Google浏览器，导航地址：http://127.0.0.1:5984/_utils/#login，显示如下：

输入用户名：admin和密码：adminpw，此二值都是配置文件中默认值。实际开发中，肯定要进行修改！

登录成功后，显示CouchDB数据库管理界面，如下：

引用

https://blog.51cto.com/zhuxianzhong/7488553