构建Python2+Java8的 Docker 镜像

基于Python2.7.15-alpine镜像来添加 Java8 环境

Dockerfile内容如下：

#
# NOTE: THIS DOCKERFILE IS GENERATED VIA "update.sh"
#
# PLEASE DO NOT EDIT IT DIRECTLY.
#

FROM python:2.7.15-alpine

# A few reasons for installing distribution-provided OpenJDK:
#
# 1. Oracle. Licensing prevents us from redistributing the official JDK.
#
# 2. Compiling OpenJDK also requires the JDK to be installed, and it gets
# really hairy.
#
# For some sample build times, see Debian's buildd logs:
# https://buildd.debian.org/status/logs.php?pkg=openjdk-8
# Default to UTF-8 file.encoding
ENV LANG C.UTF-8
# add a simple script that can auto-detect the appropriate JAVA_HOME value
# based on whether the JDK or only the JRE is installed
RUN { \
        echo '#!/bin/sh'; \
        echo 'set -e'; \
        echo; \
        echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; \
    } > /usr/local/bin/docker-java-home \
    && chmod +x /usr/local/bin/docker-java-home
ENV JAVA_HOME /usr/lib/jvm/java-1.8-openjdk
ENV PATH $PATH:/usr/lib/jvm/java-1.8-openjdk/jre/bin:/usr/lib/jvm/java-1.8-openjdk/bin
ENV JAVA_VERSION 8u242
ENV JAVA_ALPINE_VERSION 8.242.08-r0
RUN set -x \
    && apk add --no-cache \
        openjdk8="$JAVA_ALPINE_VERSION" \
    && [ "$JAVA_HOME" = "$(docker-java-home)" ]
# If you're reading this and have any feedback on how this image could be
# improved, please open an issue or a pull request so we can discuss it!
#
# https://github.com/docker-library/openjdk/issues

构建过程中遇到的问题：

1、jdk安装包问题

fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/aarch64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/aarch64/APKINDEX.tar.gz
ERROR: unsatisfiable constraints:
  openjdk8-8.242.08-r0:
    breaks: world[openjdk8=8.191.12-r0]
The command '/bin/sh -c set -x     && apk add --no-cache         openjdk8="$JAVA_ALPINE_VERSION"     && [ "$JAVA_HOME" = "$(docker-java-home)" ]' returned a non-zero code: 1

根据以上信息可知，Dockerfile中设置的apk add --no-cache 'openjdk8=8.191.12-r0' 没有找到安装包，提示说可以使用openjdk8-8.242.08-r0这个版本。相应的也需要Dockerfile中ENV JAVA_VERSION 8u191设置为对应的版本ENV JAVA_VERSION 8u242。

2、网络问题

+ apk add --no-cache 'openjdk8=8.242.08-r0'
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz: temporary error (try again later)
  openjdk8 (missing):
    required by: world[openjdk8=8.242.08-r0]
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz: temporary error (try again later)
ERROR: unsatisfiable constraints:
The command '/bin/sh -c set -x     && apk add --no-cache         openjdk8="$JAVA_ALPINE_VERSION"     && [ "$JAVA_HOME" = "$(docker-java-home)" ]' returned a non-zero code: 1

根据以上信息可知，APKINDEX.tar.gz没有下载成功，不能继续执行命令，只能找个网络比较好的环境重试。

构建成功截图：

安装jre和jdk时比较慢

镜像已上传到dockerhub，拉取命令：
docker pull cherishpf/python2-java8-alpine:1.0