Why can't I connect to postgres container outside of docker-compose? - postgresql

Question

I am doing (or planning to do) some spatial db work with OpenStreetMaps data using Postgres. I am working on a mac m1, and decided the best way is to run a Postgres db with PostGis installed in a docker container. I can't connect from my host machine, but I can connect from another container added in the same docker-compose.
In order to set the database up for importing OSM data, I need to change some of the config values, as well as install PostGis. So I have written my own dockerfile that completes these tasks on startup. To do so I use a two .sh files. This dockerfile works mostly correctly, as I can connect from another docker container running pgadmin4, but my backend application, azure data studio, and psql from terminal cannot connect, getting could not connect to server: Operation timed out Is the server running on host "172.31.0.2" and accepting TCP/IP connections on port 5432?.
My assumption is that I'm missing or adding something incorrectly when I run the Postgres container but no amount of googling bears fruit! Any help would be amazing.
Docker compose
version: '3.8'
services:
db:
build:
./database
environment:
- POSTGRES_HOST_AUTH_METHOD=trust
ports:
- "5432:5432"
Dockerfile
FROM postgres:14-bullseye
LABEL maintainer="PostGIS Project - https://postgis.net"
ENV POSTGIS_MAJOR 3
ENV POSTGIS_VERSION 3.3.2+dfsg-1.pgdg110+1
RUN apt-get update \
&& apt-cache showpkg postgresql-$PG_MAJOR-postgis-$POSTGIS_MAJOR \
&& apt-get install -y --no-install-recommends \
# ca-certificates: for accessing remote raster files;
# fix: https://github.com/postgis/docker-postgis/issues/307
ca-certificates \
\
postgresql-$PG_MAJOR-postgis-$POSTGIS_MAJOR=$POSTGIS_VERSION \
postgresql-$PG_MAJOR-postgis-$POSTGIS_MAJOR-scripts \
&& rm -rf /var/lib/apt/lists/*
RUN mkdir -p /docker-entrypoint-initdb.d
COPY ./initdb-postgis.sh /docker-entrypoint-initdb.d/10_postgis.sh
COPY ./update-postgis.sh /usr/local/bin
Essentially a copy of the postgis docker image, but that allows me to install other extensions in the initdb-postgis.sh and update-postgis.sh files, shown below:
initdb-postgis.sh
#!/bin/sh
set -e
export PGUSER="$POSTGRES_USER"
"${psql[#]}" <<- 'EOSQL'
ALTER SYSTEM SET listen_addresses = '*';
ALTER SYSTEM SET wal_level = minimal;
ALTER SYSTEM SET max_wal_senders = 0;
ALTER SYSTEM SET checkpoint_timeout = '1d';
ALTER SYSTEM SET checkpoint_completion_target = 0.90;
ALTER SYSTEM SET shared_buffers = '8GB';
ALTER SYSTEM SET max_wal_size = '10GB';
ALTER SYSTEM SET min_wal_size = '1GB';
CREATE DATABASE template_postgis IS_TEMPLATE true;
EOSQL
for DB in template_postgis "$POSTGRES_DB"; do
echo "Loading PostGIS extensions into $DB"
"${psql[#]}" --dbname="$DB" <<-'EOSQL'
CREATE EXTENSION IF NOT EXISTS postgis;
CREATE EXTENSION IF NOT EXISTS postgis_topology;
CREATE EXTENSION IF NOT EXISTS hstore;
EOSQL
done
update-postgis.sh
#!/bin/sh
set -e
export PGUSER="$POSTGRES_USER"
POSTGIS_VERSION="${POSTGIS_VERSION%%+*}"
for DB in template_postgis "$POSTGRES_DB" "${#}"; do
echo "Updating PostGIS extensions '$DB' to $POSTGIS_VERSION"
psql --dbname="$DB" -c "
-- Upgrade PostGIS (includes raster)
CREATE EXTENSION IF NOT EXISTS postgis VERSION '$POSTGIS_VERSION';
ALTER EXTENSION postgis UPDATE TO '$POSTGIS_VERSION';
-- Upgrade Topology
CREATE EXTENSION IF NOT EXISTS postgis_topology VERSION '$POSTGIS_VERSION';
ALTER EXTENSION postgis_topology UPDATE TO '$POSTGIS_VERSION';
-- Upgrade hstore
CREATE EXTENSION IF NOT EXISTS hstore;
"
I'm connecting from the host using the IP given when I docker inspect the container id, so the docker compose network shouldn't be an issue. As I mentioned before, connection works fine from inside the docker compose, with both a pgadmin4 and unix script running osm2pgsql. Both can connect using either the IP from docker inspect, or the name of the service, in this case 'db'.
Whilst I admit I am relitively inexperienced with both docker and postgis, normally some amount of googling helps me find the issue, but no this time - please help!

Answer 1

It turns out that other processes (namely other postgres db's) were running on port 5432. So following this post fixed the issue, and I can now connect using psql.