TestContainers Scala Cassandra Random Ports - scala

Question

I am running tests in scala using spark and cassandra, for the test I am using testcontainers and for some work reasons we are not using the scala variant of testcontainers, the problem with testcontainers the ports are randomly assigned and I don't know what parameter to use to get the port so I can conect
//code block
#RunWith(classOf[JUnitRunner])
class ConnectorSpec extends AnyFlatSpec
with BeforeAndAfterAll{
val container = new CassandraContainer("cassandra:latest")
container.withExposedPorts(9042)
container.waitingFor(Wait.forListeningPort())
container.start()
val ip = container.getContainerIpAddress() //output localhost
val port = container.getMappedPort(9042)
val cluster = container.getCluster()
val session = cluster.connect()
session.execute("CREATE KEYSPACE IF NOT EXISTS test WITH replication = {'class':'SimpleStrategy','replication_factor':'1'};")
session.execute("CREATE TABLE IF NOT EXISTS test.eureka (id int PRIMARY KEY, city varchar, role varchar);")
session.execute("INSERT INTO test.tester (id, city, role) VALUES (1, 'Jakarta', 'Devops')")
session.execute("SELECT * FROM test.tester")
assert(container.isRunning)
val spark = SparkSession
.builder()
.appName("ReadCassandra")
.master("local[*]")
.getOrCreate()
spark.setCassandraConf(CassandraConnectorConf.KeepAliveMillisParam.option(10000))
spark.setCassandraConf(cluster.getClusterName(), CassandraConnectorConf.ConnectionHostParam.option("127.0.0.1"))
val df = spark.read
.format("org.apache.spark.sql.cassandra")
.options(Map( "table" -> "tester", "keyspace" -> "test"))
.load()
df.show()
#sbt dependency
libraryDependencies += "org.testcontainers" % "cassandra" % "1.15.3" % Test
Output showing Actual port
Testing started at 5:30 PM ...
Connected to the target VM, address: '127.0.0.1:53611', transport: 'socket'
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/kenneth/.cache/coursier/v1/https/repo1.maven.org/maven2/org/slf4j/slf4j-log4j12/1.7.16/slf4j-log4j12-1.7.16.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/kenneth/.cache/coursier/v1/https/repo1.maven.org/maven2/org/slf4j/slf4j-nop/1.7.30/slf4j-nop-1.7.30.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.

Answer 1

You already have the local port in your code:
val port = container.getMappedPort(9042)
TestContainers provide getMappedPort specifically for this purpose: it will give you the local port mapped to the port specified as parameter in the container (the local port mapped to 9042 in Cassandra container in your case).
Note: you must start the container before calling getMappedPort but that is already your case.