无法连接 docker 容器中的 postgres

Question

I'm using Docker on Windows to use in local a postgres database. I made two docker container: one for the database called pg and another called pgadmin with pgadmin4. After inspected pg, I connected pgadmin4 in 172.17.0.3:5432 and it works. Now time to code but...

psycopg2.OperationalError: could not connect to server: Connection timed out (0x0000274C/10060)
        Is the server running on host "172.17.0.3" and accepting
        TCP/IP connections on port 5432?

I read a lot of questions like that, but i can't figure it out. Doesn't seem, to me, like a problem generated in pg_hba.conf for the denied connection, because in this case pgadmin should not work, right? (But if is a problem with pg_hba.conf where I can find it? In the docker installation folder I did't find it)

I put my python code here but don't seems the problem:

conn = psycopg2.connect(
    database = 'example',
    user = 'username',
    password = 'secretpassword',
    host = '172.17.0.3', # default port is 5432 so it's not necessary
)

Upgrade edit: I found the configurations In postgresql.conf the listen_addresses = '*', that is correct. In pg_hba.conf:

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# "local" is for Unix domain socket connections only
local   all             all                                     trust
# IPv4 local connections:
host    all             all             127.0.0.1/32            trust
# IPv6 local connections:
host    all             all             ::1/128                 trust
# Allow replication connections from localhost, by a user with the
# replication privilege.
local   replication     all                                     trust
host    replication     all             127.0.0.1/32            trust
host    replication     all             ::1/128                 trust

Answer 1

You could use docker run and the --expose parameter to expose your ports, on each container.

Another command you can run is docker network connect which allows you to connect a container to a network, so if two containers are on the same network, they should be able to communicate with each other.

The usage is docker network connect [OPTIONS] NETWORK CONTAINER

One advantage of using the docker network create command is to be able to create an --ip-range so to specify ip addresses to be used on the network.

Afterwards you can assign a container to have a specific ip address, docker network connect . If the container was not on the network for example, the ip address would not be reassigned to another container on the network.

More information in the docker documentation, https://docs.docker.com/engine/reference/commandline/network_connect/