Docker Scala Application Example

Docker allows us to execute Scala application. Here, we are creating a Scala file and executing that using the docker. This example includes the following steps.

1. Create a directory to organize application files.
$ mkdir scala-docker-app

2. Change working directory
$ cd scala-docker-app

3. Create a Dockerfile

// Dockerfile

FROM williamyeh/java7 MAINTAINER William Yeh <william.pjyeh@gmail.com> ENV SCALA_VERSION 2.10.4 ENV SCALA_TARBALL http://www.scala-lang.org/files/archive/scala-$SCALA_VERSION.deb RUN \ echo "==> Install curl helper tool..."&& \ apt-get update && \ DEBIAN_FRONTEND=noninteractive apt-get install -y --force-yes curl && \ \ \ \ echo "===> install from Typesafe repo (contains old versions but they have all dependencies we need later on)"&& \ curl -sSL http://apt.typesafe.com/repo-deb-build-0002.deb -o repo-deb.deb && \ dpkg -i repo-deb.deb && \ apt-get update && \ \ \ \ echo "===> install Scala"&& \ DEBIAN_FRONTEND=noninteractive \ apt-get install -y --force-yes libjansi-java && \ curl -sSL $SCALA_TARBALL -o scala.deb && \ dpkg -i scala.deb && \ \ \ \ echo "===> clean up..."&& \ rm -f *.deb && \ apt-get remove -y --auto-remove curl && \ apt-get clean && \ rm -rf /var/lib/apt/lists/* COPY . /root WORKDIR /root Run scalac index.scala
4. Create a Scala file

// index.scala

object MainObject{ def main(args:Array[String]){ println("Hello by Scala"); } }
5. Create a Docker Image

Now, we are creating a Docker image of this Scala application. The following command is used to create Docker image.

$ docker build -t scala-app .

6. Run Scala Docker image
$ docker run scala-app