How to connect to postgres created with docker-compose from outside host

Question

I think this problem should be very easy to solve, but I am pulling my hair out. I have the following docker-compose:

version: "3"
services:

  pg-db:
    image: postgres:11
    environment:
      POSTGRES_PASSWORD: "postgres"
      POSTGRES_USER: "postgres"
      POSTGRES_DB: "postgres"
    ports:
      - 5432:5432
    #network_mode: host

Then I run docker-compose up and it starts the container

pg-db_1_78e7ec4a95e6 | 2020-02-21 13:53:53.928 UTC [1] LOG:  database system is ready to accept connections

I can connect to it with docker exec

docker exec -it docker_pg-db-compose_1_78e7ec4a95e6 psql -h pg-db -U postgres postgres

But I can't manage to connect to it by 'naked' psql:

psql postgresql://postgres:postgres@localhost:5432/postgres

psql: could not connect to server: Connection refused
    Is the server running on host "localhost" (::1) and accepting
    TCP/IP connections on port 5432?

psql postgresql://postgres:postgres@pg-dg:5432/postgres
psql: could not translate host name "pg-db" to address: Name or service not known

I've tried with network_mode but it doesn't help.

Answer 1

After starting docker-compose, you need to get the docker container ip by doing this:

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' container_name_or_id

Then you can do postgresql://postgres:postgres@<container idp>:5432/postgres you should be able to connect to it

Answer 2

I'm using a modified version of the docker-compose file provided in the Postgres DockerHub page.

version: '3.1'
services:
  db:
    image: postgres:11
    restart: always
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: postgres

When I run docker-compose up I get a very similar "ready" message:

db_1  | 2020-02-21 14:34:17.826 UTC [1] LOG:  database system is ready to accept connections

At this point, I can connect to Postgres using psql.

$ psql -h localhost -U postgres
Password for user postgres: 
psql (12.2, server 11.7 (Debian 11.7-1.pgdg90+1))
Type "help" for help.

postgres=#

I'm also able to connect using the connection string that you provided, and postico:

The differences are subtle, I'm not sure if the restart policy makes any difference here, but give it a try.