Question

我有一个Dockerfile，它有Scala和SBT，如下所示：

# Scala and sbt Dockerfile
# Scala and SBT forked from: https://github.com/hseeberger/scala-sbt
# Adds Docker client installation additionally

# Pull base image
FROM  openjdk:$JAVA_VERSION

ARG SCALA_VERSION
ARG SBT_VERSION

# Scala expects this file
RUN touch /usr/lib/jvm/java-$JAVA_VERSION-openjdk-amd64/release

# Install Scala
## Piping curl directly in tar
RUN \
  curl -fsL http://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz | tar xfz - -C /root/ && \
  echo >> /root/.bashrc && \
  echo 'export PATH=~/scala-$SCALA_VERSION/bin:$PATH' >> /root/.bashrc

# Install sbt
RUN \
  curl -L -o sbt-$SBT_VERSION.deb http://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && \
  dpkg -i sbt-$SBT_VERSION.deb && \
  rm sbt-$SBT_VERSION.deb && \
  apt-get update && \
  apt-get install sbt && \
  sbt sbtVersion

现在，如果我想将此作为我的基本图像，我有以下问题：

我可以覆盖新Dockerfile中的ARG参数吗？这些参数将使用上面的那个作为基本图像？

Answer 1

每个Dockerfile都会生成一个不可变的图像。因此，您需要首先构建一个特定的基本映像，然后构建自己的FROM它。

你可以采用这种方法：

Dockerfile.base：

# Scala and sbt Dockerfile
# Scala and SBT forked from: https://github.com/hseeberger/scala-sbt
# Adds Docker client installation additionally

# Pull base image
ARG JAVA_VERSION
FROM  openjdk:$JAVA_VERSION

ARG SCALA_VERSION
ARG SBT_VERSION

# Scala expects this file
RUN touch /usr/lib/jvm/java-$JAVA_VERSION-openjdk-amd64/release

# Install Scala
## Piping curl directly in tar
RUN \
  curl -fsL http://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz | tar xfz - -C /root/ && \
  echo >> /root/.bashrc && \
  echo 'export PATH=~/scala-$SCALA_VERSION/bin:$PATH' >> /root/.bashrc

# Install sbt
RUN \
  curl -L -o sbt-$SBT_VERSION.deb http://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && \
  dpkg -i sbt-$SBT_VERSION.deb && \
  rm sbt-$SBT_VERSION.deb && \
  apt-get update && \
  apt-get install sbt && \
  sbt sbtVersion

您的孩子Dockerfile Dockerfile.mine：

ARG JAVA_VERSION
ARG SCALA_VERSION
ARG SBT_VERSION
FROM basejava:java-$JAVA_VERSION-scala-$SCALA_VERSION-sbt-$SBT_VERSION
# Your app stuf here
# ...
# ...

构建示例：

 export JAVA_VERSION=latest
 export SCALA_VERSION=1.8
 export SBT_VERSION=0.13.9
 docker build . \
   -f Dockerfile.base \
   --build-arg JAVA_VERSION=$JAVA_VERSION \
   --build-arg SCALA_VERSION=$SCALA_VERSION \
   --build-arg SBT_VERSION=$SBT_VERSION \
   -t basejava:java-$JAVA_VERSION-scala-$SCALA_VERSION-sbt-$SBT_VERSION

 docker build . \
   -f Dockerfile.mine \
   --build-arg JAVA_VERSION=latest \
   --build-arg SCALA_VERSION=1.8 \
   --build-arg SBT_VERSION=0.13.9
   -t myjava:java-$JAVA_VERSION-scala-$SCALA_VERSION-sbt-$SBT_VERSION

接近2 ，ONBUILD，由zigarn提及。

Dockerfile.base：

# Scala and sbt Dockerfile
# Scala and SBT forked from: https://github.com/hseeberger/scala-sbt
# Adds Docker client installation additionally

# Pull base image
ONBUILD ARG JAVA_VERSION
FROM  openjdk:$JAVA_VERSION

ONBUILD ARG SCALA_VERSION
ONBUILD ARG SBT_VERSION

# Scala expects this file
ONBUILD RUN touch /usr/lib/jvm/java-$JAVA_VERSION-openjdk-amd64/release

# Install Scala
## Piping curl directly in tar
ONBUILD RUN \
  curl -fsL http://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz | tar xfz - -C /root/ && \
  echo >> /root/.bashrc && \
  echo 'export PATH=~/scala-$SCALA_VERSION/bin:$PATH' >> /root/.bashrc

# Install sbt
ONBUILD RUN \
  curl -L -o sbt-$SBT_VERSION.deb http://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && \
  dpkg -i sbt-$SBT_VERSION.deb && \
  rm sbt-$SBT_VERSION.deb && \
  apt-get update && \
  apt-get install sbt && \
  sbt sbtVersion

您的孩子Dockerfile.mine

FROM basejava
# Base ONLBUILD instructions are automatically inserted here.
# Your app stuf here
# ...
# ...

构建

docker build . -f Dockerfile.base -t basejava

export JAVA_VERSION=latest
export SCALA_VERSION=1.8
export SBT_VERSION=0.13.9
docker build . \
   -f Dockerfile.mine \
   --build-arg JAVA_VERSION=$JAVA_VERSION \
   --build-arg SCALA_VERSION=$SCALA_VERSION \
   --build-arg SBT_VERSION=$SBT_VERSION \
   -t myjava:java-$JAVA_VERSION-scala-$SCALA_VERSION-sbt-$SBT_VERSION

Answer 2

ARG值在构建时定义构建基础映像后，您不能只更改--build-arg以在最终映像中获取另一个SCALA_VERSION（或者您必须在新的Dockerfile中再次安装它）

目前的Dockerfile就像是其他Dockerfile的模板您可以使用ONBUILD instruction在构建其他图像期间有效地进行安装，使用此图像作为基本图像。

Dockerfile覆盖ARG值

2 个答案: