Connection to 127.0.0.1 refused in a Dockerfile based on postgres:17-alpine3.20

[Alexander Farber <alexander.farber@xxxxxxxxx>]

Good evening,

I am trying to create a Dockerfile for development purposes, which 

would run Jetty and PostgreSQL. The PostgreSQL related part is below:

FROM postgres:17-alpine3.20

RUN apk update && apk upgrade && apk add --no-cache curl wget openjdk21 tini

# Tell docker-entrypoint.sh to create superuser "postgres"

# with password "mypassword" and database "postgres"

ENV POSTGRES_PASSWORD mypassword

# Tell docker-entrypoint.sh to change these params in postgresql.conf

ENV POSTGRES_INITDB_ARGS "--set port=6432 --set max_connections=20 --set max_wal_size=2GB"

# The PostgreSQL port is changed from 5432 to 6432 to emulate pg_bouncer

ENV PGPORT 6432

ENV PGUSER words

ENV PGPASSWORD mypassword

WORKDIR /docker-entrypoint-initdb.d

COPY ["run-after-initdb.sh", "."]

RUN chmod +x run-after-initdb.sh && cat run-after-initdb.sh

USER postgres

EXPOSE 6432 9090

ENTRYPOINT ["/sbin/tini", "--"]

CMD ["sh", "-c", "docker-entrypoint.sh postgres & cd $JETTY_BASE && sleep 10 && java -Djdbc.drivers=org.postgresql.Driver -jar $JETTY_HOME/start.jar"]

And below is my run-after-initdb.sh script:

#!/bin/sh

createuser --username=postgres words

psql --username=postgres -c "GRANT USAGE ON SCHEMA public TO words;"

psql --username=postgres -c "ALTER USER words PASSWORD 'mypassword';"

for L in de en ru fr nl pl; do

    createdb --username=postgres --owner=words words_$L

    cd /dict/$L && psql words_$L < words_$L.sql

done

Then I build and run the docker image and that works without errors:

# docker build -t my_docker_image --progress=plain .

# docker run --name my_container -p 8080:8080 -p 6432:6432 my_docker_image

When I connect to the docker container via terminal, 

I am able to connect with "psql words_de" command.

But the "psql -h localhost words_de" command fails:

psql: error: connection to server at "localhost" (127.0.0.1), port 6432 failed: Connection refused

        Is the server running on that host and accepting TCP/IP connections?

connection to server at "localhost" (::1), port 6432 failed: Address not available

        Is the server running on that host and accepting TCP/IP connections?

I need the connection via 127.0.0.1 though, 

because of my Java servlet hosted by the Jetty.

I have looked at the config files and env vars:

# ls -al /var/run/postgresql/

srwxrwxrwx    1 postgres postgres         0 Dec  1 19:06 .s.PGSQL.6432

-rw-------    1 postgres postgres        64 Dec  1 19:06 .s.PGSQL.6432.lock

# echo $PGDATA

/var/lib/postgresql/data

# grep -v '^#' $PGDATA/pg_hba.conf

local   all             all                                     trust

host    all             all             127.0.0.1/32            trust

host    all             all             ::1/128                 trust

local   replication     all                                     trust

host    replication     all             127.0.0.1/32            trust

host    replication     all             ::1/128                 trust

# grep -v '^.*#' $PGDATA/postgresql.conf

listen_addresses = '*'

max_wal_size = 2GB

min_wal_size = 80MB

log_timezone = UTC

datestyle = 'iso, mdy'

timezone = UTC

default_text_search_config = 'pg_catalog.english'

Is anybody able spotting, what am I doing wrong here? Thank you

TLDR "psql words_de" works, but "psql -h localhost words_de" does not

Best regards
Alex