使用Docker和Kotlin缓存Maven

Question

在构建Kotlin项目之前，我正在尝试预热Docker + Maven缓存。正如许多Maven/Docker线程所建议的那样，我的docker文件如下所示：

COPY pom.xml .
RUN  mvn dependency:go-offline
COPY ./src/ src/
RUN  mvn package

我的想法是，如果我更改./src目录中的文件，我希望docker cache跳过maven冗长的依赖项下载页面。

我的问题是mvn package命令仍然会下载很多文件。我尝试使用mvn -o package (maven离线标志)来诊断缺少哪些依赖项，但它只是报告它无法下载依赖项。但是我已经预料到依赖项已经在上一步中被下载了。下面是我使用"-o“标志得到的错误：

Step 8/13 : RUN  mvn dependency:go-offline
 ---> Using cache
 ---> 0334facb9cc9
Step 9/13 : COPY ./src/ src/
 ---> Using cache
 ---> 27149a191017
Step 10/13 : RUN  mvn -o package
 ---> Running in 5183eced32ca
Warning: JAVA_HOME environment variable is not set.
[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building auth 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ auth ---
[WARNING] The POM for org.apache.maven:maven-core:jar:2.0.6 is missing, no dependency information available
[WARNING] The POM for org.apache.maven:maven-monitor:jar:2.0.6 is missing, no dependency information available
[WARNING] The POM for org.codehaus.plexus:plexus-utils:jar:2.0.5 is missing, no dependency information available
[WARNING] The POM for org.apache.maven.shared:maven-filtering:jar:1.1 is missing, no dependency information available
[WARNING] The POM for org.codehaus.plexus:plexus-interpolation:jar:1.13 is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.882 s
[INFO] Finished at: 2019-07-12T07:02:23+00:00
[INFO] Final Memory: 13M/174M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.6:resources (default-resources) on project auth: Execution default-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.6:resources failed: Plugin org.apache.maven.plugins:maven-resources-plugin:2.6 or one of its dependencies could not be resolved: The following artifacts could not be resolved: org.apache.maven:maven-plugin-api:jar:2.0.6, org.apache.maven:maven-project:jar:2.0.6, org.apache.maven:maven-profile:jar:2.0.6, org.apache.maven:maven-artifact-manager:jar:2.0.6, org.apache.maven:maven-repository-metadata:jar:2.0.6, org.apache.maven:maven-plugin-registry:jar:2.0.6, org.apache.maven:maven-core:jar:2.0.6, org.apache.maven:maven-artifact:jar:2.0.6, org.apache.maven:maven-settings:jar:2.0.6, org.apache.maven:maven-model:jar:2.0.6, org.apache.maven:maven-monitor:jar:2.0.6, classworlds:classworlds:jar:1.1-alpha-2, org.codehaus.plexus:plexus-utils:jar:2.0.5, org.apache.maven.shared:maven-filtering:jar:1.1, org.codehaus.plexus:plexus-interpolation:jar:1.13: Cannot access central (https://repo.maven.apache.org/maven2) in offline mode and the artifact org.apache.maven:maven-plugin-api:jar:2.0.6 has not been downloaded from it before. -> [Help 1

Answer 1

尝试使用mvn命令，它将我从maven错误中解救出来。

RUN  mvn --batch-mode --errors --strict-checksums --threads 1C \
     org.apache.maven.plugins:maven-dependency-plugin:3.0.2:go-offline

RUN  mvn --batch-mode --errors --offline package

Answer 2

根据我从各种来源收集的信息，go-offline并不总是以正确的方式处理缓存包，将其中一些包留在本地存储库之外(请参阅GitHub上的拉取请求)。

在我的例子中，标准mvn dependency:go-offline使用go-offline 2.8并返回错误。然后我尝试运行mvn org.apache.maven.plugins:maven-dependency-plugin:3.2.0:go-offline，但我仍然在使用不同的包时遇到了一些问题。

对我来说起作用的是使用了GitHub上提供的一个不同的"go-offline“插件。

使用

mvn de.qaware.maven:go-offline-maven-plugin:resolve-dependencies

终于完成了任务。