Docker Scala應用程式示例

Docker允許我們執行Scala應用程式。 在這裏，我們將演示如何創建一個Scala檔，並使用docker進行執行，此示例包括以下步驟。

1. 創建一個目錄用來組織應用程式檔。

$ mkdir - /home/zaixian/docker/scala-docker-app

1. 更改進入工作目錄

$ cd /home/zaixian/docker/scala-docker-app

1. 創建一個名稱為 Dockerfile 的 Dockerfile 檔

FROM williamyeh/java7
MAINTAINER Hema (xuhuhu.com@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 . /home/zaixian/src
WORKDIR /home/zaixian/src
CMD ["scala", "/home/zaixian/src/index.scala"]

1. 創建Scala檔: /home/zaixian/docker/scala-docker-app/index.scala

object MainObject{
    def main(args:Array[String]){
        println("Hello by Scala");
    }
}

現在，創建這個Scala應用程式的Docker映像。 以下命令用於創建Docker映像。

zaixian@ubuntu:~/docker/scala-docker-app$ sudo docker build -t scala-app .

執行上面代碼，輸出結果如下 -

zaixian@ubuntu:~/docker/scala-docker-app$ sudo docker build -t scala-app .
Sending build context to Docker daemon  3.584kB
.......
Removing intermediate container a551438ab33a
......
 ---> Running in bc8b748316cc
 ---> 1d786cf20101
Removing intermediate container bc8b748316cc
Successfully built 1d786cf20101
Successfully tagged scala-app:latest
zaixian@ubuntu:~/docker/scala-docker-app$

1. 運行Scala Docker映像

zaixian@ubuntu:~/docker/scala-docker-app$ sudo docker run scala-app

執行上面代碼，得到以下結果 -

zaixian@ubuntu:~/docker/scala-docker-app$ sudo docker run scala-app
Hello by Scala
zaixian@ubuntu:~/docker/scala-docker-app$ sudo docker run scala-app