docker-compose.yml

version: "3"
services:
    minio:
        image: minio/minio
        environment:
            - MINIO_ACCESS_KEY=TESTKEY
            - MINIO_SECRET_KEY=TESTSECRET
        ports:
            - "9001:9000"
        command: ["server", "/data"]

UseMinio.scala

package sample

import java.io.{BufferedReader, InputStreamReader}

import com.amazonaws.auth.{AWSStaticCredentialsProvider, BasicAWSCredentials}
import com.amazonaws.client.builder.AwsClientBuilder.EndpointConfiguration
import com.amazonaws.services.s3.{AmazonS3, AmazonS3ClientBuilder}
import sample.FilePath
import org.scalatest._

import scala.collection.JavaConverters._

trait UseMinio extends BeforeAndAfterAll { self: Suite =>

  private val accessKey = "TESTKEY"
  private val secret = "TESTSECRET"
  private val endpointUrl = "http://localhost:9001"
  private val staticProvider = new AWSStaticCredentialsProvider(new BasicAWSCredentials(accessKey, secret))

  lazy val s3Client: AmazonS3 = AmazonS3ClientBuilder.standard
    .withCredentials(staticProvider)
    .withEndpointConfiguration(new EndpointConfiguration(endpointUrl, "ap-northeast-1"))
    .withPathStyleAccessEnabled(true)
    .build()

  def bucketName: String = "test-bucket"

  override def beforeAll(): Unit = {
    super.beforeAll()
    if (s3Client.doesBucketExistV2(bucketName)) {
      emptyS3Bucket(bucketName)
    } else {
      createS3Bucket(bucketName)
    }
  }

  private def emptyS3Bucket(bucketName: String): Unit = {
    val list = s3Client.listObjects(bucketName)
    list.getObjectSummaries.asScala foreach { obj =>
      s3Client.deleteObject(bucketName, obj.getKey)
    }
  }

  private def createS3Bucket(bucketName: String): Unit =
    s3Client.createBucket(bucketName)

  def putS3(s3File: FilePath.S3, content: String): Unit =
    s3Client.putObject(s3File.bucketName, s3File.key, content)

  def getLines(s3File: FilePath.S3): Seq[String] = {
    val (bucketName, key) = (s3File.bucketName, s3File.key)
    val br = new BufferedReader(new InputStreamReader(s3Client.getObject(bucketName, key).getObjectContent))
    var lines = Seq.empty[String]
    try {
      var line = br.readLine()
      while (line != null) {
        lines = lines :+ line
        line = br.readLine()
      }
    } finally {
      br.close()
    }
    lines
  }

}