Timed out waiting for container port to open (localhost ports: [32773] should be listening)

Question

I am trying to use https://github.com/testcontainers/testcontainers-scala that is inherent from https://www.testcontainers.org/ as the following:

final class MessageSpec extends BddSpec
  with ForAllTestContainer
  with BeforeAndAfterAll {


  override val container = GenericContainer("sweetsoft/sapmock").configure{ c =>
    c.addExposedPort(8080)
    c.withNetwork(Network.newNetwork())
  }

  override def beforeAll() {
  }


  feature("Process incoming messages") {  

When I run the test with the command sbt test, I've got the following exception:

15:22:23.171 [pool-7-thread-2] ERROR 🐳 [sweetsoft/sapmock:latest] - Could not start container
org.testcontainers.containers.ContainerLaunchException: Timed out waiting for container port to open (localhost ports: [32775] should be listening)
        at org.testcontainers.containers.wait.strategy.HostPortWaitStrategy.waitUntilReady(HostPortWaitStrategy.java:47)
        at org.testcontainers.containers.wait.strategy.AbstractWaitStrategy.waitUntilReady(AbstractWaitStrategy.java:35)
        at org.testcontainers.containers.wait.HostPortWaitStrategy.waitUntilReady(HostPortWaitStrategy.java:23)
        at org.testcontainers.containers.wait.strategy.AbstractWaitStrategy.waitUntilReady(AbstractWaitStrategy.java:35)
        at org.testcontainers.containers.GenericContainer.waitUntilContainerStarted(GenericContainer.java:582)

The image is a local image:

docker images
REPOSITORY                    TAG                 IMAGE ID            CREATED             SIZE
sweetsoft/sapmock             latest              f02be90356e7        3 hours ago         664MB
openjdk                       8                   bec43387959a        11 days ago         625MB
quay.io/testcontainers/ryuk   0.2.3               64849fd2d464        3 months ago        10.7MB

The question is, why is it waiting for 32775 port? And for what is the port good for?

Update

Maybe this log will help:

15:47:47.274 [pool-7-thread-4] INFO org.testcontainers.dockerclient.DockerClientProviderStrategy - Found Docker environment with Environment variables, system properties and defaults. Resolved: 
    dockerHost=unix:///var/run/docker.sock
    apiVersion='{UNKNOWN_VERSION}'
    registryUrl='https://index.docker.io/v1/'
    registryUsername='developer'
    registryPassword='null'
    registryEmail='null'
    dockerConfig='DefaultDockerClientConfig[dockerHost=unix:///var/run/docker.sock,registryUsername=developer,registryPassword=<null>,registryEmail=<null>,registryUrl=https://index.docker.io/v1/,dockerConfigPath=/home/developer/.docker,sslConfig=<null>,apiVersion={UNKNOWN_VERSION},dockerConfig=<null>]'

15:47:47.275 [pool-7-thread-4] INFO org.testcontainers.DockerClientFactory - Docker host IP address is localhost
15:47:47.277 [pool-7-thread-4] DEBUG com.github.dockerjava.core.command.AbstrDockerCmd - Cmd: com.github.dockerjava.core.exec.InfoCmdExec@51a07bb5
15:47:47.389 [pool-7-thread-4] DEBUG com.github.dockerjava.core.command.AbstrDockerCmd - Cmd: com.github.dockerjava.core.exec.VersionCmdExec@70fc9b37
15:47:47.392 [pool-7-thread-4] INFO org.testcontainers.DockerClientFactory - Connected to docker: 
  Server Version: 18.09.6
  API Version: 1.39
  Operating System: Ubuntu 18.04.2 LTS
  Total Memory: 7976 MB
15:47:47.395 [pool-7-thread-4] DEBUG com.github.dockerjava.core.command.AbstrDockerCmd - Cmd: ListImagesCmdImpl[imageNameFilter=quay.io/testcontainers/ryuk:0.2.3,showAll=false,filters=com.github.dockerjava.core.util.FiltersBuilder@0,execution=com.github.dockerjava.core.exec.ListImagesCmdExec@562a343]
15:47:47.417 [pool-7-thread-4] DEBUG org.testcontainers.utility.RegistryAuthLocator - Looking up auth config for image: quay.io/testcontainers/ryuk:0.2.3
15:47:47.417 [pool-7-thread-4] DEBUG org.testcontainers.utility.RegistryAuthLocator - RegistryAuthLocator has configFile: /home/developer/.docker/config.json (does not exist) and commandPathPrefix: 
15:47:47.418 [pool-7-thread-4] WARN org.testcontainers.utility.RegistryAuthLocator - Failure when attempting to lookup auth config (dockerImageName: quay.io/testcontainers/ryuk:0.2.3, configFile: /home/developer/.docker/config.json. Falling back to docker-java default behaviour. Exception message: /home/developer/.docker/config.json (No such file or directory)
15:47:47.418 [pool-7-thread-4] DEBUG org.testcontainers.dockerclient.auth.AuthDelegatingDockerClientConfig - Effective auth config [null]

Answer 1

Original java library has answer to your port question.
https://www.testcontainers.org/features/networking/

Note that this exposed port number is from the perspective of the container.

From the host's perspective Testcontainers actually exposes this on a random free port. This is by design, to avoid port collisions that may arise with locally running software or in between parallel test runs.

Because there is this layer of indirection, it is necessary to ask Testcontainers for the actual mapped port at runtime. This can be done using the getMappedPort method, which takes the original (container) port as an argument

In Scala library you can get this mapped port by calling

container.mappedPort(yourExposedPort) 

Error is most likely related to this concept, you need to expose that port in advance, inside your docker image. Make sure that you either have expose 8080 command somewhere in your dockerfile or any image that is used to build yours have it