Golang gocql无法连接Cassandra (使用Docker)

Question

我正在尝试使用docker和Golang设置并连接到Cassandra单节点实例，但它不起作用。

我能找到的最接近解决golang gocql包和Cassandra之间的连接问题的信息可以在这里找到：Cassandra cqlsh - connection refused，但是有许多不同的向上投票答案，没有明确的指示。这也是一个受保护的问题(不包括"me toos")，因此许多社区成员似乎对此有困难。

这个问题应该略有不同，因为它使用的Docker和我已经尝试了大部分(如果不是所有的解决方案链接到上面)。

version: "3"  
services:  
  cassandra00:
    restart: always
    image: cassandra:latest
    volumes: 
      - ./db/casdata:/var/lib/cassandra
    ports: 
      - 7000:7000
      - 7001:7001
      - 7199:7199
      - 9042:9042
      - 9160:9160
    environment:
      - CASSANDRA_RPC_ADDRESS=127.0.0.1
      - CASSANDRA_BROADCAST_ADDRESS=127.0.0.1
      - CASSANDRA_LISTEN_ADDRESS=127.0.0.1
      - CASSANDRA_START_RPC=true
  db:
    restart: always
    build: ./db
    environment:
      POSTGRES_USER: patientplatypus
      POSTGRES_PASSWORD: SUPERSECRETFAKEPASSD00T
      POSTGRES_DB: zennify
    expose:
      - "5432"
    ports:
      - 5432:5432
    volumes:
      - ./db/pgdata:/var/lib/postgresql/data
  app:
    restart: always
    build: 
      context: .
      dockerfile: Dockerfile
    command: bash -c 'while !</dev/tcp/db/5432; do sleep 10; done; realize start --run'
    # command: bash -c 'while !</dev/tcp/db/5432; do sleep 10; done; go run main.go'
    ports:
      - 8000:8000
    depends_on:
      - db
      - cassandra00
    links:
      - db
      - cassandra00
    volumes:
      - ./:/go/src/github.com/patientplatypus/webserver/

诚然，我在环境部分应该传递给Cassandra的哪些收听地址有点不稳定，所以我只是路过了'home'：

  - CASSANDRA_RPC_ADDRESS=127.0.0.1
  - CASSANDRA_BROADCAST_ADDRESS=127.0.0.1
  - CASSANDRA_LISTEN_ADDRESS=127.0.0.1

如果尝试传递0.0.0.0，则会得到以下错误：

cassandra00_1  | Exception (org.apache.cassandra.exceptions.ConfigurationException) encountered during startup: listen_address cannot be a wildcard address (0.0.0.0)!
cassandra00_1  | listen_address cannot be a wildcard address (0.0.0.0)!
cassandra00_1  | ERROR [main] 2018-09-10 21:50:44,530 CassandraDaemon.java:708 - Exception encountered during startup: listen_address cannot be a wildcard address (0.0.0.0)!

不过，总的来说，我认为为Cassandra (afaict)获得了正确的启动程序，因为我的终端输出Cassandra正常启动并监听适当的端口：

cassandra00_1  | INFO  [main] 2018-09-10 22:06:28,920 StorageService.java:1446 - JOINING: Finish joining ring
cassandra00_1  | INFO  [main] 2018-09-10 22:06:29,179 StorageService.java:2289 - Node /127.0.0.1 state jump to NORMAL
cassandra00_1  | INFO  [main] 2018-09-10 22:06:29,607 NativeTransportService.java:70 - Netty using native Epoll event loop
cassandra00_1  | INFO  [main] 2018-09-10 22:06:29,750 Server.java:155 - Using Netty Version: [netty-buffer=netty-buffer-4.0.44.Final.452812a, netty-codec=netty-codec-4.0.44.Final.452812a, netty-codec-haproxy=netty-codec-haproxy-4.0.44.Final.452812a, netty-codec-http=netty-codec-http-4.0.44.Final.452812a, netty-codec-socks=netty-codec-socks-4.0.44.Final.452812a, netty-common=netty-common-4.0.44.Final.452812a, netty-handler=netty-handler-4.0.44.Final.452812a, netty-tcnative=netty-tcnative-1.1.33.Fork26.142ecbb, netty-transport=netty-transport-4.0.44.Final.452812a, netty-transport-native-epoll=netty-transport-native-epoll-4.0.44.Final.452812a, netty-transport-rxtx=netty-transport-rxtx-4.0.44.Final.452812a, netty-transport-sctp=netty-transport-sctp-4.0.44.Final.452812a, netty-transport-udt=netty-transport-udt-4.0.44.Final.452812a]
cassandra00_1  | INFO  [main] 2018-09-10 22:06:29,754 Server.java:156 - Starting listening for CQL clients on /127.0.0.1:9042 (unencrypted)...
cassandra00_1  | INFO  [main] 2018-09-10 22:06:29,990 ThriftServer.java:116 - Binding thrift service to /127.0.0.1:9160

在我的golang代码中，我有以下正在被调用的包(简化为显示相关部分)：

package data

import(
    "fmt"
    "github.com/gocql/gocql"
)

func create_userinfo_table() {
    <...>
    fmt.Println("replicating table in cassandra")
    cluster := gocql.NewCluster("localhost") //<---error here!
    cluster.ProtoVersion = 4
    <...>
}

这将导致我的终端出现以下错误：

app_1          | [21:52:38][WEBSERVER] : 2018/09/10 
21:52:38 gocql: unable to dial control conn 127.0.0.1: 
dial tcp 127.0.0.1:9042: connect: connection refused

app_1          | [21:52:38][WEBSERVER] : 2018/09/10 
21:52:38 gocql: unable to dial control conn ::1: 
dial tcp [::1]:9042: connect: cannot assign requested address

app_1          | [21:52:38][WEBSERVER] : 2018/09/10 
21:52:38 Could not connect to cassandra cluster: gocql: 
unable to create session: control: unable to connect to initial hosts: 
dial tcp [::1]:9042: connect: cannot assign requested address

我试过几种不同的连接地址

cluster := gocql.NewCluster("localhost")

cluster := gocql.NewCluster("127.0.0.1")

cluster := gocql.NewCluster("127.0.0.1:9042")

cluster := gocql.NewCluster("127.0.0.1:9160")

例如，这些似乎很有可能成为候选人，但却没有运气。

有人知道我做错了什么吗？

Answer 1

使用服务名称cassandra00作为停靠者-组合文档https://docs.docker.com/compose/compose-file/#links的主机名。

可在与别名相同的主机名上访问链接服务的容器，如果未指定别名，则可访问服务名称。

保留CASSANDRA_LISTEN_ADDRESS envvar未设置(或传递auto)给每个https://docs.docker.com/samples/library/cassandra/

默认值是auto，它将在容器启动时将listen_address选项在cassandra.yaml中设置为容器的IP地址。此默认设置在大多数用例中都能工作。