CouchDB
CouchDB是一种NoSQL解决方案。它是一个面向文档的数据库，其中文档字段存储为键值映射。字段可以是简单的键值对，列表或映射。除了LevelDB支持的键值查询/复合键查询/范围查询外，CouchDB还支持数据的完全查询功能，例如对整个区块链数据的非键值查询，因为CouchDB的数据是以JSON存储的，所以可以实现完全查询。CouchDB可以支持许多LevelDB不支持的链码审计、报告的要求。
CouchDB还可以增强区块链中的合规性和数据保护的安全性。因为它能够通过过滤和屏蔽事务中的各个属性来实现字段级安全性，并且只在需要时授权只读权限。
此外，CouchDB属于CAP定理的AP类型（可用性和分区容差）。它使用master-master高可用模型。在每一个fabric节点中，不会有数据库的副本，因此写入到数据库操作需要确保一致性和持久性，它是不能确保最终一致性的数据库。
CouchDB是Fabric的第一个外部可插拔的状态数据库，未来会支持更多的数据库。IBM内部支持了关系型数据库。同时在某些场景下也需要一些能够支持C-P类型的（一致性、分区容忍性）的数据！
替换LevelDB
first-network网络默认使用的数据库方案是go-leveldb，替换为CouchDB。CouchDB除了能支持leveldb的方法，还能实现丰富而又复杂的查询，数据库的序列化采用JSON。
首先清理原有网络
echo y | ./byfn.sh down
docker rm -f $(docker ps -aq)
接下来需要首先生成证书等，由于byfn.sh脚本更加方便，我们直接使用它
echo y | ./byfn.sh -m generate
启动网络
docker-compose -f docker-compose-cli.yaml -f docker-compose-couch.yaml up -d
启动网络之后看到网络中添加了couchdb的容器
docker ps -a
CONTAINER ID IMAGE COMMAND CREATED PORTS NAMES
60285f9fcf93 hyperledger/fabric-tools:latest "/bin/bash" About a minute ago cli
0e50ff0569b3 hyperledger/fabric-peer:latest "peer node start" About a minute ago 0.0.0.0:8051->7051/tcp, 0.0.0.0:8053->7053/tcp peer1.org1.example.com
fded9f702e7b hyperledger/fabric-peer:latest "peer node start" About a minute ago 0.0.0.0:9051->7051/tcp, 0.0.0.0:9053->7053/tcp peer0.org2.example.com
31f3134bfce3 hyperledger/fabric-peer:latest "peer node start" About a minute ago 0.0.0.0:10051->7051/tcp, 0.0.0.0:10053->7053/tcp peer1.org2.example.com
6c11075f9d35 hyperledger/fabric-peer:latest "peer node start" About a minute ago 0.0.0.0:7051->7051/tcp, 0.0.0.0:7053->7053/tcp peer0.org1.example.com
c78e46e749f6 hyperledger/fabric-couchdb "tini -- /docker-e..." 2 minutes ago 4369/tcp, 9100/tcp, 0.0.0.0:8984->5984/tcp couchdb3
a29280255587 hyperledger/fabric-couchdb "tini -- /docker-e..." 2 minutes ago 4369/tcp, 9100/tcp, 0.0.0.0:6984->5984/tcp couchdb1
a93bd7270c34 hyperledger/fabric-orderer:latest "orderer" 2 minutes ago 0.0.0.0:7050->7050/tcp orderer.example.com
38f0b7d00e47 hyperledger/fabric-couchdb "tini -- /docker-e..." 2 minutes ago 4369/tcp, 9100/tcp, 0.0.0.0:5984->5984/tcp couchdb0
b9870083a99a hyperledger/fabric-couchdb "tini -- /docker-e..." 2 minutes ago 4369/tcp, 9100/tcp, 0.0.0.0:7984->5984/tcp couchdb2
就是在启动的时候添加了docker-compose-couch.yaml的描述文件
进入到cli容器中
docker exec -it cli bash
创建channel
export CHANNEL_NAME=mychannel && peer channel create -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/channel.tx \
--tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
2018-10-30 02:27:21.940 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2018-10-30 02:27:22.013 UTC [cli/common] readBlock -> INFO 002 Received block: 0
将节点peer0.org1.example.com和peer0.org2.example.com分别加入到channel中
peer0.org1.example.com
peer channel join -b mychannel.block
2018-10-30 02:27:47.240 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2018-10-30 02:27:47.488 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
peer0.org2.example.com
CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp \
CORE_PEER_ADDRESS=peer0.org2.example.com:7051 CORE_PEER_LOCALMSPID="Org2MSP" \
CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \
peer channel join -b mychannel.block
2018-10-30 02:28:03.189 UTC [channelCmd] InitCmdFactory -> INFO 001 Endorser and orderer connections initialized
2018-10-30 02:28:03.433 UTC [channelCmd] executeJoin -> INFO 002 Successfully submitted proposal to join channel
指定锚节点peer0.org1.example.com
peer channel update -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/Org1MSPanchors.tx --tls \
--cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
peer0.org2.example.com
CORE_PEER_MSPCONFIGPATH=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/users/Admin@org2.example.com/msp \
CORE_PEER_ADDRESS=peer0.org2.example.com:7051 CORE_PEER_LOCALMSPID="Org2MSP" \
CORE_PEER_TLS_ROOTCERT_FILE=/opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/peerOrganizations/org2.example.com/peers/peer0.org2.example.com/tls/ca.crt \
peer channel update -o orderer.example.com:7050 -c $CHANNEL_NAME -f ./channel-artifacts/Org2MSPanchors.tx --tls \
--cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem
查看是否有安装链码
peer chaincode list --installed
Get installed chaincodes on peer:
目前没有任何链码安装好，接下来我们使用github.com/chaincode/marbles02/go中的marbles_chaincode.go链码。
marbles_chaincode.go
执行
peer chaincode install -n marbles -v 1.0 -p github.com/chaincode/marbles02/go
实例化链码
peer chaincode instantiate -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -v 1.0 -c '{"Args":["init"]}' -P "OR ('Org0MSP.peer','Org1MSP.peer')"
创建一些marbles
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble1","blue","35","tom"]}' && \
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble2","red","50","tom"]}' && \
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["initMarble","marble3","blue","70","tom"]}' && \
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["transferMarble","marble2","jerry"]}' && \
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["transferMarblesBasedOnColor","blue","jerry"]}' && \
peer chaincode invoke -o orderer.example.com:7050 --tls --cafile /opt/gopath/src/github.com/hyperledger/fabric/peer/crypto/ordererOrganizations/example.com/orderers/orderer.example.com/msp/tlscacerts/tlsca.example.com-cert.pem -C $CHANNEL_NAME -n marbles -c '{"Args":["delete","marble1"]}'
在docker-compose描述文件docker-compose-couch.yaml文件中
services:
couchdb0:
container_name: couchdb0
image: hyperledger/fabric-couchdb
# 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=
- COUCHDB_PASSWORD=
# 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"
指明了couchdb容器对应的端口映射，因此我们可以通过外部网络访问couchdb的web接口Fauxton，但是这个操作在生产环境中是不建议的，会出现安全问题http://localhost:5984/_utils
查询marble2
peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["readMarble","marble2"]}'
{
"color": "red",
"docType": "marble",
"name": "marble2",
"owner": "jerry",
"size": 50
}
查询marble1的历史记录
peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["getHistoryForMarble","marble1"]}'
[
{
"TxId": "d351f7c4f61e669cc0f254844a268b015941241d6aaf63981bad090ab064761d",
"Value": {
"docType": "marble",
"name": "marble1",
"color": "blue",
"size": 35,
"owner": "tom"
},
"Timestamp": "2018-10-30 06:18:52.643796107 +0000 UTC",
"IsDelete": "false"
},
{
"TxId": "0411b642b0db5bd8075260f980ac977e6da066188b59f833d5ff8aba8cdb6abb",
"Value": {
"docType": "marble",
"name": "marble1",
"color": "blue",
"size": 35,
"owner": "jerry"
},
"Timestamp": "2018-10-30 06:19:23.043823665 +0000 UTC",
"IsDelete": "false"
},
{
"TxId": "f94737b23a19215be035d651fa470b3a8e8dfd2c5b6c7bb54d72c3242d50ced6",
"Value": null,
"Timestamp": "2018-10-30 06:19:28.865157343 +0000 UTC",
"IsDelete": "true"
},
{
"TxId": "e131b63ce74e964b9cbc95ac0bdb5bd45ef2d412e46953499ea2d1ab2d847560",
"Value": {
"docType": "marble",
"name": "marble1",
"color": "blue",
"size": 35,
"owner": "tom"
},
"Timestamp": "2018-10-30 06:46:10.905922106 +0000 UTC",
"IsDelete": "false"
}
]
同样还可以根据作者查询marble
peer chaincode query -C $CHANNEL_NAME -n marbles -c '{"Args":["queryMarblesByOwner","jerry"]}'
[
{
"Key": "marble2",
"Record": {
"color": "red",
"docType": "marble",
"name": "marble2",
"owner": "jerry",
"size": 50
}
},
{
"Key": "marble3",
"Record": {
"color": "blue",
"docType": "marble",
"name": "marble3",
"owner": "jerry",
"size": 70
}
}
]
结
CouchDB能够带来更加丰富的查询操作，相比于LevelDB来说更加适合作为Fabric底层的数据库。
