Myujth

My docker compose file is:

version: '3'
services:
 postgres:
 container_name: crm-psql
 image: postgres:9.3
 restart: always
 environment:
 - POSTGRES_DB=crm
 - POSTGRES_USER=root
 - POSTGRES_PASSWORD=root
 volumes:
 - ./db/postgres/data:/var/lib/postgresql/data
 ports:
 - 5432:5432
 nginx:
 container_name: crm-nginx
 image: nginx:1.15
 restart: always
 ports:
 - 80:80
 - 443:443
 volumes:
 - ./nginx/conf.d:/etc/nginx/conf.d
 web:
 build: .
 ports:
 - 9000:9000
 volumes:
 - .:/src/main/java
 - ~/.ivy2:/root/.ivy2
 - ~/.sbt:/root/.sbt
 links:
 - postgres
 - nginx

The docker file for build is:

FROM openjdk:8
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $PATH:/usr/lib/jvm/java-1.8-openjdk/jre/bin:/usr/lib/jvm/java-1.8-openjdk/bin

ENV SBT_VERSION 1.2.1

# Install curl
RUN 
 apt-get update && 
 apt-get -y install curl && 
 apt-get -y install vim

# Install sbt
RUN 
 curl -L -o sbt-$SBT_VERSION.deb https://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && 
 dpkg -i sbt-$SBT_VERSION.deb && 
 rm sbt-$SBT_VERSION.deb && 
 apt-get update && 
 apt-get -y install sbt

WORKDIR /src/main/java
COPY . /src/main/java
RUN sbt update
EXPOSE 9000
ENTRYPOINT ["sbt", "run"]

Whenever I do docker-compose up, the connection doesn't gets established to postgres. The exception is

org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

However when i exec in container crm-psql and type psql crm, it goes into postgres shell. What is the issue here

I think your problem is that you use localhost to indicate your database. You should use your link instead. From the point of view of your "sbt" container, localhost is itself and not your local machine (with the port forwarding) or your postgresql container.

Generaly what I use is environment variables.

links:
 - postgres
 - nginx
environment: 
 - POSTGRES_SERVICE_HOST=postgres

After you need to specify in your SBT script how to use your POSTGRES_SERVICE_HOST variable