Schemacrawler容器无法连接本地PostgreSQL数据库求助

在Ubuntu 18.04上运行SchemaCrawler Docker容器时，无法连接到本地PostgreSQL数据库，报错连接被拒绝。已修改postgresql.conf设置listen_addresses = '*'，并在pg_hba.conf添加host all all 0.0.0.0/0 md5，但问题依旧。

运行的命令：

docker run \
--mount type=bind,source="$(pwd)",target=/home/schcrwlr \
--rm -it \
schemacrawler/schemacrawler:v16.19.7 \
/opt/schemacrawler/bin/schemacrawler.sh \
--server postgresql \
--host localhost \
--user postgres \
--password pass \
--database detections \
--info-level standard \
--command schema \
--output-file output.png

错误信息：

Error: Could not connect to <jdbc:postgresql://localhost:5432/detections>, for <user 'postgres'>, with properties <{}>
java.lang.RuntimeException: Could not connect to <jdbc:postgresql://localhost:5432/detections>, for <user 'postgres'>, with properties <{}>
    at us.fatehi.utility.datasource.AbstractDatabaseConnectionSource.getConnection(AbstractDatabaseConnectionSource.java:131)
    at us.fatehi.utility.datasource.SimpleDatabaseConnectionSource.get(SimpleDatabaseConnectionSource.java:112)
    at us.fatehi.utility.datasource.SimpleDatabaseConnectionSource.get(SimpleDatabaseConnectionSource.java:49)
    at schemacrawler.tools.commandline.command.ConnectCommand.loadSchemaRetrievalOptionsBuilder(ConnectCommand.java:180)
    at schemacrawler.tools.commandline.command.ConnectCommand.run(ConnectCommand.java:124)
    at schemacrawler.tools.commandline.SchemaCrawlerCommandLine.executeCommandLine(SchemaCrawlerCommandLine.java:110)
    at schemacrawler.tools.commandline.SchemaCrawlerCommandLine.execute(SchemaCrawlerCommandLine.java:72)
    at schemacrawler.Main.main(Main.java:76)
Caused by: org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:319)
    at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
    at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:247)
    at org.postgresql.Driver.makeConnection(Driver.java:434)
    at org.postgresql.Driver.connect(Driver.java:291)
    at us.fatehi.utility.datasource.AbstractDatabaseConnectionSource.getConnection(AbstractDatabaseConnectionSource.java:122)
    ... 7 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:412)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:255)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:237)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.base/java.net.Socket.connect(Socket.java:609)
    at org.postgresql.core.PGStream.createSocket(PGStream.java:241)
    at org.postgresql.core.PGStream.<init>(PGStream.java:98)
    at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:109)
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:235)

问题核心是Docker容器的网络隔离：容器内的localhost指向容器自身，而非宿主机的PostgreSQL服务。以下是两种可行的解决方法：

方法1：使用宿主机的Docker内部IP #

1. 查找宿主机在Docker网络中的网关IP：

   ip addr show docker0
   

   输出中inet字段对应的IP（通常为172.17.0.1）就是容器可访问的宿主机地址。

2. 修改SchemaCrawler命令的--host参数为该IP：

   docker run \
   --mount type=bind,source="$(pwd)",target=/home/schcrwlr \
   --rm -it \
   schemacrawler/schemacrawler:v16.19.7 \
   /opt/schemacrawler/bin/schemacrawler.sh \
   --server postgresql \
   --host 172.17.0.1 \  # 替换为实际查到的Docker网关IP
   --user postgres \
   --password pass \
   --database detections \
   --info-level standard \
   --command schema \
   --output-file output.png
   

方法2：使用Docker host网络模式 #

运行容器时添加--network host参数，让容器直接使用宿主机的网络栈，此时容器内的localhost等同于宿主机的localhost：

docker run \
--mount type=bind,source="$(pwd)",target=/home/schcrwlr \
--rm -it \
--network host \
schemacrawler/schemacrawler:v16.19.7 \
/opt/schemacrawler/bin/schemacrawler.sh \
--server postgresql \
--host localhost \
--user postgres \
--password pass \
--database detections \
--info-level standard \
--command schema \
--output-file output.png

额外验证步骤 #

• 重启PostgreSQL服务，确保配置修改生效：

  sudo systemctl restart postgresql
  

• 在宿主机本地执行psql -h localhost -U postgres detections，验证数据库服务本身可正常连接。

内容的提问来源于stack exchange，提问作者laos