I created a docker image with Postgres via Dockerfile:
FROM postgres:9.6-alpine
After I started this docker container, I'm checking that it's up and running using a connection from the different docker container that has pre-installed psql:
docker run -it --rm --link ml-postgres:postgres postgres:12.2-alpine psql --dbname mlpython -h postgres -U postgres
The result is that I'm able to connect to the first container with postgres and perform all regular operations with the postgres DB.
Troubles begin when I want to connect to the container with postgres DB from a Python script that I created locally:
import psycopg2
conn = psycopg2.connect(
host="127.0.0.1",
database="mlpython",
user="postgres",
password="test",
port="5431"
)
cur = conn.cursor()
cursor.execute('SELECT COUNT(*) FROM mytable LIMIT 10')
cur.close()
Here is an error which I get:
> psycopg2.OperationalError: server closed the connection unexpectedly
> This probably means the server terminated abnormally before or while
> processing the request.
What do I miss while trying to bootstrap this simple code sample where Python interacts with Postgres?
docker run -poption for it to be accessible from outside Docker; with that connection string, something likedocker run -p 5431:5432 postgres:9.6-alpine(the second port number must be the default port 5432 but the first can be anything).