getting connection refused from docker containers in a same docker compose - docker

Question

i have an akka http application and one keycloak docker container
i used sbt native docker plugin to create a an image of my app and then i wrote a docker compose file but my app container is not discovering keycloak container
here is my build.sbt file
enablePlugins(DockerPlugin)
enablePlugins(JavaAppPackaging)
dockerExposedPorts := Seq(8083)
then i created a docker image of my project
>docker:publishLocal
then i created a docker-compose file
version: '3.3'
services:
keycloak:
image: jboss/keycloak
container_name: docker-keycloak-container
ports:
- "8080:8080"
environment:
- KEYCLOAK_USER=admin
- KEYCLOAK_PASSWORD=admin
akkahttpservice:
image: myproject-auth:0.0.1
container_name: docker-myproject-auth-container
ports:
- "8083:8083"
depends_on:
- keycloak
docker ps shows
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
181522f78d22 myproject-auth:0.0.1 "/opt/docker/bin/int…" 45 seconds ago Up 40 seconds 0.0.0.0:8083->8083/tcp docker-myproject-auth-container
d92d9c4f0a19 jboss/keycloak "/opt/jboss/tools/do…" 5 days ago Up 46 seconds 0.0.0.0:8080->8080/tcp, 8443/tcp docker-keycloak-container
but when i hit my applications route which talks to keycloak i got
14:13:32.020 [scala-execution-context-global-45] ERROR com.ifkaar.lufz.authentication.actors.worker.TokenManagerActor - Actor TokenManager: exception in fetching token
docker-myproject-auth-container | akka.stream.StreamTcpException: Tcp command [Connect(0.0.0.0:8080,None,List(),Some(10 seconds),true)] failed because of java.net.ConnectException: Connection refused
docker-myproject-auth-container | Caused by: java.net.ConnectException: Connection refused
docker-myproject-auth-container | at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
docker-myproject-auth-container | at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:714)
docker-myproject-auth-container | at akka.io.TcpOutgoingConnection$$anonfun$connecting$1.$anonfun$applyOrElse$4(TcpOutgoingConnection.scala:111)
docker-myproject-auth-container | at akka.io.TcpOutgoingConnection.akka$io$TcpOutgoingConnection$$reportConnectFailure(TcpOutgoingConnection.scala:53)
docker-myproject-auth-container | at akka.io.TcpOutgoingConnection$$anonfun$connecting$1.applyOrElse(TcpOutgoingConnection.scala:111)
docker-myproject-auth-container | at akka.actor.Actor.aroundReceive(Actor.scala:537)
docker-myproject-auth-container | at akka.actor.Actor.aroundReceive$(Actor.scala:535)
docker-myproject-auth-container | at akka.io.TcpConnection.aroundReceive(TcpConnection.scala:33)
docker-myproject-auth-container | at akka.actor.ActorCell.receiveMessage(ActorCell.scala:577)
docker-myproject-auth-container | at akka.actor.ActorCell.invoke(ActorCell.scala:547)
docker-myproject-auth-container | at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:270)
docker-myproject-auth-container | at akka.dispatch.Mailbox.run(Mailbox.scala:231)
docker-myproject-auth-container | at akka.dispatch.Mailbox.exec(Mailbox.scala:243)
docker-myproject-auth-container | at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
docker-myproject-auth-container | at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
docker-myproject-auth-container | at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
docker-myproject-auth-container | at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
but everything works when i run my app from sbt and use docker keycloak container why is that so ?
also i am running my akka http project on http://0.0.0.0:8083
kindly guide me on this

Answer 1

You need to inject address of keycloak into your service via environment variable. For this you can use service name as keycloak address (Compose docs)
services:
keycloak:
image: jboss/keycloak
container_name: docker-keycloak-container
ports:
- "8080:8080"
environment:
- KEYCLOAK_USER=admin
- KEYCLOAK_PASSWORD=admin
akkahttpservice:
image: myproject-auth:0.0.1
container_name: docker-myproject-auth-container
environment:
- KEYCLOAK_URL: "http://keycloak:8080"
ports:
- "8083:8083"
depends_on:
- keycloak