Docker Compose部署Commento无法连接Postgres问题求助

错误日志 #

2023/02/01 08:34:35 [INFO] version.go:13 versionPrint(): starting Commento
2023/02/01 08:34:35 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:34:35 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (4 attempts left): dial tcp 172.18.0.2:5432: connect: connection refused
2023/02/01 08:34:45 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:34:45 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (3 attempts left): pq: unknown authentication response: 10
2023/02/01 08:34:55 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:34:55 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (2 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:05 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:35:06 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (1 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:16 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:35:16 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (0 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:26 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted@db:5432/commento?sslmode=disable
2023/02/01 08:35:26 [ERROR] database_connect.go:35 dbConnect(): cannot talk to postgres, last attempt failed: pq: unknown authentication response: 10
fatal error: pq: unknown authentication response: 10

复现步骤 #

• 在全新Ubuntu 22.04LTS服务器上安装docker和docker-compose。
• 创建服务目录，使用以下docker-compose.yml配置：

version: '3'

services:
  server:
    image: registry.gitlab.com/commento/commento:SET_VERSION
    ports:
      - 8080:8080
    environment:
      COMMENTO_ORIGIN: http://commento.example.com:8080
      COMMENTO_PORT: 8080
      COMMENTO_POSTGRES: postgres://postgres:postgres@db:5432/commento?sslmode=disable
    depends_on:
      - db
  db:
    image: postgres
    environment:
      POSTGRES_DB: commento
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
    volumes:
      - postgres_data_volume:/var/lib/postgresql/data

volumes:
  postgres_data_volume:

• 执行docker-compose up -d后查看服务日志，commento_server_1服务出现上述错误。

修复方法 #

原因说明 #

unknown authentication response: 10错误是因为PostgreSQL 14+默认使用scram-sha-256认证方式，而旧版本Commento使用的pq数据库驱动不支持该认证，导致连接失败。

方案1：指定PostgreSQL兼容版本 #

修改docker-compose.yml中的postgres镜像版本，使用PostgreSQL 13或更低版本（比如13-alpine），这些版本默认使用旧的md5认证：

db:
  image: postgres:13-alpine  # 替换原postgres镜像
  environment:
    POSTGRES_DB: commento
    POSTGRES_USER: postgres
    POSTGRES_PASSWORD: postgres
  volumes:
    - postgres_data_volume:/var/lib/postgresql/data

修改后执行以下命令重启服务：

docker-compose down -v  # 删除旧数据卷，避免残留配置
docker-compose up -d

方案2：强制PostgreSQL使用md5认证 #

如果不想降低PostgreSQL版本，可以在db服务中添加环境变量POSTGRES_INITDB_ARGS，强制初始化时使用md5认证：

db:
  image: postgres
  environment:
    POSTGRES_DB: commento
    POSTGRES_USER: postgres
    POSTGRES_PASSWORD: postgres
    POSTGRES_INITDB_ARGS: "--auth-host=md5"  # 添加该行
  volumes:
    - postgres_data_volume:/var/lib/postgresql/data

同样需要删除旧数据卷后重启：

docker-compose down -v
docker-compose up -d

额外注意事项 #

• 确保COMMENTO_POSTGRES环境变量中的用户名、密码、数据库名和postgres服务的配置完全一致。
• depends_on仅保证服务启动顺序，不保证postgres完全就绪，Commento本身有重试机制，所以不用额外添加健康检查（如果重试后仍失败，就是认证问题）。

内容的提问来源于stack exchange，提问作者dummytokken