Dockerfile特殊转义符号

Question

当我使用带有'-- build -arg‘的命令来构建对接图像时，传入参数中的空格将被替换为加号。

我的pom.xml：

<plugin>
   <groupId>com.spotify</groupId>
    <artifactId>dockerfile-maven-plugin</artifactId>
    <version>1.4.13</version>
    <configuration>
      <repository>192.168.1.200/library/${project.artifactId}</repository>
      <tag>${project.version}</tag>
      <buildArgs>
         <JAR_FILE>${project.build.finalName}.jar</JAR_FILE>
         <JVM_OPTS>-Xms300m -Xmx300m</JVM_OPTS>
      </buildArgs>
    </configuration>
</plugin>

我的Dockerfile：

FROM 192.168.1.200/library/openjdk:8-jdk-alpine
MAINTAINER gaojiayiner@163.com
LABEL version="1.0.0"
RUN mkdir -p /project && mkdir -p /data
ENV workdir /project
WORKDIR $workdir
ARG JAR_FILE
ARG JVM_OPTS
ENV jvm $JVM_OPTS
COPY target/${JAR_FILE} /project/demo.jar
EXPOSE 8080
ENTRYPOINT ["sh","-c","java -jar /project/demo.jar $0 $@"]

终端执行记录：

[root@localhost docker-java]# mvn clean package dockerfile:build
[root@localhost docker-java]# docker images
REPOSITORY                      TAG                 IMAGE ID            CREATED             SIZE
192.168.1.200/library/demo      0.0.1-SNAPSHOT      13373a4761a1        3 seconds ago       131MB
192.168.1.200/library/openjdk   8-jdk-alpine        a3562aa0b991        14 months ago       105MB
[root@localhost docker-java]# docker run -d  13373a4761a1
d0b5ce9392b12505419d5648332f204dc3d59327efd389c27a950aa0d1daba35
[root@localhost docker-java]# docker ps
CONTAINER ID        IMAGE                    COMMAND                  CREATED             STATUS              PORTS                                            NAMES
d0b5ce9392b1        13373a4761a1             "sh -c 'java -jar /p…"   4 seconds ago       Up 4 seconds        8080/tcp                                         reverent_kirch
[root@localhost docker-java]# docker exec -it d0b5ce9392b1 sh
/project # env
jvm=-Xms300m+-Xmx300m
JAVA_ALPINE_VERSION=8.212.04-r0
HOSTNAME=d0b5ce9392b1

您可以看到代码jvm=-Xms300m+-Xmx300m.我怎么才能解决这个问题？

Answer 1

您需要自己重新编译spotify/dockerfile-maven，因为修复此bug的拉请求尚未合并/接受。

见"spotify/dockerfile-maven PR 350“

它指出了罪魁祸首：plugin/dockerfile/BuildMojo.java#encodeBuildParam

  private static String encodeBuildParam(Object buildParam) throws MojoExecutionException {
    try {
      return URLEncoder.encode(new Gson().toJson(buildParam), "utf-8");
    } catch (UnsupportedEncodingException e) {
      throw new MojoExecutionException("Could not build image", e);
    }
  }

的确，我们可以读到here (class URLEncoder)，URLEncoder将空格字符“”替换为加号"+“。

编码之后，我添加了一个替换，将+符号替换为空格:编码之后，所有加号都将被编码为/0x2B，所以剩下的是来自空格的符号。

解决办法将包括：

      return URLEncoder.encode(
               new Gson().toJson(buildParam), StandardCharsets.UTF_8.toString()
             ).replace('+', ' ');
              ^^^^^^^^^^^^^^^^^^^