Docker Compose构建失败：changes out of order报错求助

问题背景 #

执行docker-compose build时触发报错：failed to solve: changes out of order: "target/diplomAPI-0.0.1-SNAPSHOT.jar" ""。已确认diplomAPI-0.0.1-SNAPSHOT.jar存在于target目录，Dockerfile与docker-compose.yml位于同一目录，尝试删除ARG行、分离配置文件目录等操作均无效。

原Dockerfile内容 #

FROM openjdk:alpine
ARG JAR_FILE=target/*.jar
COPY ./target/diplomAPI-0.0.1-SNAPSHOT.jar app.jar

ENTRYPOINT ["java", "-jar", "/app.jar"]

原docker-compose.yml内容 #

version: '3'
services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "8080:8080"
    depends_on:
      - db
  db:
    image: postgres
    restart: always
    ports:
      - "5432:5432"
    environment:
      POSTGRES_DB: mobilka
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: 12345

完整错误日志 #

PS C:\Users\extre\IdeaProjects\diplomAPI> docker-compose build
[+] Building 0.0s (0/0)  docker:default
[+] Building 0.0s (0/0)  docker:defaultr reading preface from client //./pipe/docker_engine: file has already been closed
[+] Building 2.2s (6/7)                                                                                                                                                                                              docker:default
 => [app internal] load build definition from Dockerfile                                                                                                                                                                       0.0s
 => => transferring dockerfile: 180B                                                                                                                                                                                           0.0s 
 => [app internal] load metadata for docker.io/library/openjdk:alpine                                                                                                                                                          2.0s 
 => [app auth] library/openjdk:pull token for registry-1.docker.io                                                                                                                                                             0.0s
 => [app internal] load .dockerignore                                                                                                                                                                                          0.0s
 => => transferring context: 2B                                                                                                                                                                                                0.0s 
 => ERROR [app internal] load build context                                                                                                                                                                                    0.0s 
 => => transferring context: 57B                                                                                                                                                                                               0.0s 
 => [app 1/2] FROM docker.io/library/openjdk:alpine@sha256:1fd5a77d82536c88486e526da26ae79b6cd8a14006eb3da3a25eb8d2d682ccd6                                                                                                    0.0s 
------
 > [app internal] load build context:
------
failed to solve: changes out of order: "target/diplomAPI-0.0.1-SNAPSHOT.jar" ""

解决方法 #

• 检查.dockerignore文件：这个错误大多因为构建上下文被错误过滤。打开项目根目录下的.dockerignore，确保没有target/或diplomAPI-0.0.1-SNAPSHOT.jar这类条目，若存在则删除。
• 简化Dockerfile指令：原ARG参数未实际使用，直接简化COPY路径，避免路径歧义。修改后的Dockerfile如下：

FROM openjdk:alpine
COPY target/diplomAPI-0.0.1-SNAPSHOT.jar app.jar
ENTRYPOINT ["java", "-jar", "/app.jar"]

• 清理Docker构建缓存：缓存异常可能导致此类问题，执行以下命令清理缓存后重新构建：

docker builder prune
docker-compose build

• 确认工作目录：确保执行docker-compose build时，当前终端所在目录是项目根目录（即包含target文件夹的目录），若不是则先通过cd命令切换到对应目录。

内容的提问来源于stack exchange，提问作者Andy Good