Fabric启用CouchDB

状态数据库

启用CouchDB

  编写节点配置文件及CouchDB配置文件docker-compose-couchdb.yaml

version: '2' 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" 

  以上为最简配置,仅包含用户名、密码、端口等信息，更多配置项可查阅相关的资料。启动CouchDB容器：

docker-compose -f ../docker-compose-couchdb.yaml up -d 

  在peer节点的配置文件中增加以下配置项

- 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 - CORE_LEDGER_STATE_COUCHDBCONFIG_PASSWORD= 

  启动相应容器，OK，基础环境已经完成。

链码常见API

 GetState(key string) ([]byte, error) PutState(key string, value []byte) error GetStateByRange(startKey, endKey string) (StateQueryIteratorInterface, error) GetStateByPartialCompositeKey(objectType string, keys []string) (StateQueryIteratorInterface, error) 

  对于CouchDB的富查询，API提供了 GetQueryResult(query string) (StateQueryIteratorInterface, error) 接口，其中参数query string格式参考CouchDB JSON 查询语法

{ "selector": { "year": {"$gt": 2010} }, "fields": ["_id", "_rev", "year", "title"], "sort": [{"year": "asc"}], "limit": 2, "skip": 0, "execution_stats": true } 

CouchDB分页

GetStateByRangeWithPagination(startKey, endKey string, pageSize int32, bookmark string) (StateQueryIteratorInterface, *pb.QueryResponseMetadata, error) GetStateByPartialCompositeKeyWithPagination(objectType string, keys []string, pageSize int32, bookmark string) (StateQueryIteratorInterface, *pb.QueryResponseMetadata, error) GetQueryResultWithPagination(query string, pageSize int32, bookmark string) (StateQueryIteratorInterface, *pb.QueryResponseMetadata, error) 

  指定查询数量（pageSize ）和书签（bookmark ），接口返回数据和下次查询的书签（对于初次查询，书签传入空字符串“”），分页查询是只读的，为了避免查询时间过长，所有的链码查询返回结果数据的最大条数都由core.yaml中的totalQueryLimit（默认值为）限定。另外无论是否启用分页，peer都会根据core.yaml中的internalQueryLimit（默认值为1000）分批查询CouchDB，以保障性能。

CouchDB索引

  索引使JSON查询更高效，并且对应排序（sort）而言，创建索引是必须的。使用方法：在链码文件所在目录，创建META-INF / statedb / couchdb / indexes目录，每个索引必须在扩展名为.json的文本文件中定义,遵循CouchDB索引的基本语法. 例如:

{"index":{"fields":["docType","owner"]},"ddoc":"indexOwnerDoc", "name":"indexOwner","type":"json"} 

通过CouchDB Fauxton interface

  CouchDB Fauxton interface 是一个WEB UI,支持外部创建索引,更新索引,地址:http://localhost:5984/_utils

通过POST请求

curl -i -X POST -H "Content-Type: application/json" -d "{\"index\":{\"fields\":[\"docType\",\"owner\"]}, \"name\":\"indexOwner\", \"ddoc\":\"indexOwnerDoc\", \"type\":\"json\"}" http://hostname:port/mychannel_marbles/_index 

curl -X DELETE http://localhost:5984/mychannel_marbles/_index/indexOwnerDoc/json/indexOwner -H "accept: */*" -H "Host: localhost:5984" 

  命令格式

curl -X DELETE http://localhost:5984/{ 
   database_name}/_index/{ 
   design_doc}/json/{ 
   index_name} -H "accept: */*" -H "Host: localhost:5984"