CI/CD流水线Maven仓库缓存异常：二次运行仍缓存未命中

问题描述 #

在CI/CD流水线中使用Maven容器镜像构建时，首次运行后已生成依赖缓存，但二次运行仍出现缓存未命中，导致流水线重复下载所有Maven依赖。

首次运行日志 #

2024-02-16T06:07:55.0601063Z ##[section]Starting: Cache Maven local repo
2024-02-16T06:07:55.0604747Z ==============================================================================
2024-02-16T06:07:55.0604864Z Task         : Cache
2024-02-16T06:07:55.0604921Z Description  : Cache files between runs
2024-02-16T06:07:55.0604995Z Version      : 2.198.0
2024-02-16T06:07:55.0605064Z Author       : Microsoft Corporation
2024-02-16T06:07:55.0605132Z Help         : https://aka.ms/pipeline-caching-docs
2024-02-16T06:07:55.0605208Z ==============================================================================
2024-02-16T06:07:55.4414221Z Resolving key:
2024-02-16T06:07:55.4553411Z  - "funcs" [string]
2024-02-16T06:07:55.4571469Z  - maven   [string]
2024-02-16T06:07:55.4571795Z  - "Linux" [string]
2024-02-16T06:07:55.5018041Z  - pom.xml [file] --> 5893AE16A5F30361F4225A94E477DB4CD1996348660AD3CFBB1F4DBF72753257
2024-02-16T06:07:55.5064081Z Resolved to: "funcs"|maven|"Linux"|EpdW7VOO9P62oHHqI9TxsjUKX3NemXThFSh/NjDbSf8=
2024-02-16T06:07:55.5126152Z Resolving restore key:
2024-02-16T06:07:55.5126751Z  - maven   [string]
2024-02-16T06:07:55.5127024Z  - "Linux" [string]
2024-02-16T06:07:55.5133145Z Resolved to: maven|"Linux"|**
2024-02-16T06:07:55.5133337Z Resolving restore key:
2024-02-16T06:07:55.5133577Z  - maven [string]
2024-02-16T06:07:55.5133821Z Resolved to: maven|**
2024-02-16T06:07:55.5592310Z Using default max parallelism.
2024-02-16T06:07:56.4382488Z Using default max parallelism.
2024-02-16T06:07:56.4391109Z Max dedup parallelism: 192
2024-02-16T06:07:56.4391465Z DomainId: 0
2024-02-16T06:07:56.5918440Z ApplicationInsightsTelemetrySender will correlate events with X-TFS-Session 2c5e36a2-f0aa-46fc-8d04-fce0bc3c204d
2024-02-16T06:07:56.5943617Z Hashtype: Dedup64K
2024-02-16T06:07:56.7734517Z Getting a pipeline cache artifact with one of the following fingerprints:
2024-02-16T06:07:56.7735134Z Fingerprint: `"funcs"|maven|"Linux"|EpdW7VOO9P62oHHqI9TxsjUKX3NemXThFSh/NjDbSf8=`
2024-02-16T06:07:56.7735886Z Fingerprint: `maven|"Linux"|**`
2024-02-16T06:07:56.7736226Z Fingerprint: `maven|**`
2024-02-16T06:07:57.3874838Z There is a cache miss.
2024-02-16T06:07:58.0799644Z ApplicationInsightsTelemetrySender correlated 1 events with X-TFS-Session 2c5e36a2-f0aa-46fc-8d04-fce0bc3c204d
2024-02-16T06:07:58.0924753Z ##[section]Finishing: Cache Maven local repo

二次运行日志 #

2024-02-16T06:21:28.1316213Z ##[section]Starting: Cache Maven local repo
2024-02-16T06:21:28.1319938Z ==============================================================================
2024-02-16T06:21:28.1320071Z Task         : Cache
2024-02-16T06:21:28.1320128Z Description  : Cache files between runs
2024-02-16T06:21:28.1320203Z Version      : 2.198.0
2024-02-16T06:21:28.1320263Z Author       : Microsoft Corporation
2024-02-16T06:21:28.1320345Z Help         : https://aka.ms/pipeline-caching-docs
2024-02-16T06:21:28.1320422Z ==============================================================================
2024-02-16T06:21:28.4851948Z Resolving key:
2024-02-16T06:21:28.5007633Z  - "funcs" [string]
2024-02-16T06:21:28.5025467Z  - maven   [string]
2024-02-16T06:21:28.5026109Z  - "Linux" [string]
2024-02-16T06:21:28.5434800Z  - pom.xml [file] --> 5893AE16A5F30361F4225A94E477DB4CD1996348660AD3CFBB1F4DBF72753257
2024-02-16T06:21:28.5478850Z Resolved to: "funcs"|maven|"Linux"|EpdW7VOO9P62oHHqI9TxsjUKX3NemXThFSh/NjDbSf8=
2024-02-16T06:21:28.5537145Z Resolving restore key:
2024-02-16T06:21:28.5537814Z  - maven   [string]
2024-02-16T06:21:28.5538343Z  - "Linux" [string]
2024-02-16T06:21:28.5543267Z Resolved to: maven|"Linux"|**
2024-02-16T06:21:28.5543652Z Resolving restore key:
2024-02-16T06:21:28.5544353Z  - maven [string]
2024-02-16T06:21:28.5544566Z Resolved to: maven|**
2024-02-16T06:21:28.5983821Z Using default max parallelism.
2024-02-16T06:21:29.4158957Z Using default max parallelism.
2024-02-16T06:21:29.4167148Z Max dedup parallelism: 192
2024-02-16T06:21:29.4169349Z DomainId: 0
2024-02-16T06:21:29.5509867Z ApplicationInsightsTelemetrySender will correlate events with X-TFS-Session e570c636-2828-41f0-a57d-df6db6a4a793
2024-02-16T06:21:29.5531316Z Hashtype: Dedup64K
2024-02-16T06:21:29.8068742Z Getting a pipeline cache artifact with one of the following fingerprints:
2024-02-16T06:21:29.8069565Z Fingerprint: `"funcs"|maven|"Linux"|EpdW7VOO9P62oHHqI9TxsjUKX3NemXThFSh/NjDbSf8=`
2024-02-16T06:21:29.8070600Z Fingerprint: `maven|"Linux"|**`
2024-02-16T06:21:29.8070948Z Fingerprint: `maven|**`
2024-02-16T06:21:30.8048244Z There is a cache miss.
2024-02-16T06:21:31.6162213Z ApplicationInsightsTelemetrySender correlated 1 events with X-TFS-Session e570c636-2828-41f0-a57d-df6db6a4a793
2024-02-16T06:21:31.6285835Z ##[section]Finishing: Cache Maven local repo

流水线配置 #

trigger:
  branches:
    include:
      - "master"

variables:
  MAVEN_CACHE_FOLDER: $(MAVEN_HOME).m2/repository
  MAVEN_OPTS: "-Dmaven.repo.local=$(MAVEN_CACHE_FOLDER)"

stages:
  - stage: Build
    displayName: "CI"
    jobs:
      - job: Build
        displayName: "Build/Test Service"
        pool:
          vmImage: ubuntu-latest
        container:
          image: maven:3.9-eclipse-temurin-21
        steps:
          - checkout: self
            fetchDepth: 0

          - task: Cache@2
            displayName: "Cache Maven local repo"
            inputs:
              key: '"funcs" | maven | "$(Agent.OS)" | pom.xml'
              restoreKeys: |
                maven | "$(Agent.OS)"
                maven
              path: $(MAVEN_CACHE_FOLDER)

          - task: Maven@3
            inputs:
              mavenPomFile: "pom.xml"
              goals: "clean install"
              options: "-DskipTests $(MAVEN_OPTS)"
            displayName: "Maven Install"

问题分析与解决方案 #

核心问题 #

配置中MAVEN_CACHE_FOLDER变量的定义缺少斜杠，导致路径拼接错误：

• 原配置：$(MAVEN_HOME).m2/repository
• 在maven容器中，MAVEN_HOME默认值为/usr/share/maven，拼接后路径变为/usr/share/maven.m2/repository——这是一个不存在的路径，Maven实际不会将依赖下载到该目录，因此Cache任务无法捕获到依赖文件，自然无法生成有效缓存。

修复步骤 #

1. 修正缓存路径变量
   将MAVEN_CACHE_FOLDER改为：

   MAVEN_CACHE_FOLDER: $(MAVEN_HOME)/.m2/repository
   

   添加斜杠后，路径变为正确的/usr/share/maven/.m2/repository，与Maven容器内的默认仓库路径一致。

2. 确保缓存目录存在
   可在Cache任务前添加步骤创建目录，避免路径不存在导致的异常：

   - script: mkdir -p $(MAVEN_CACHE_FOLDER)
     displayName: "Create Maven cache directory"
   

3. 验证缓存逻辑
   Cache@2任务会在流水线步骤结束后自动检测path指定目录的变化，将新增文件上传到缓存系统。修正路径后，Maven下载的依赖会被正确捕获，二次运行时即可命中缓存。

内容的提问来源于stack exchange，提问作者twerpiebird