TestContainers Scala Cassandra 随机端口

Question

我正在使用 spark 和 cassandra 在 scala 中运行测试，对于测试我使用的是 testcontainers 并且由于某些工作原因我们没有使用 testcontainers 的 scala 变体，testcontainers 的问题是端口是随机分配的，我没有知道使用什么参数来获取端口，以便我可以连接

//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

显示实际端口的输出

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

您的代码中已经有了本地端口：

val port = container.getMappedPort(9042)

TestContainers 专门为此目的提供getMappedPort：它将为您提供映射到容器中作为参数指定的端口的本地端口（在您的情况下，本地端口映射到 Cassandra 容器中的 9042）。

注意：您必须在调用 getMappedPort 之前启动容器，但这已经是您的情况了。