无法在 docker 多阶段构建中使用 ARG

Question

我正在尝试在 docker 多阶段构建过程中使用 ARGS。

我的 Dockerfile 如下所示：

ARG DOCKER_REGISTRY=example.com/docker
FROM $DOCKER_REGISTRY/openjdk8:latest AS installer 
ARG APP_VERSION=6.3.0.78 
ARG DOCKER_REGISTRY 
ARG REPO_TYPE=snapshot 
ARG DB_VERSION=12.2.0.11-ee
ARG DB_TYPE=oracle ARG PASSWORD

ARG DOCKER_REGISTRY 
ARG DB_VERSION 
ARG DB_TYPE
FROM ${DOCKER_REGISTRY}/${DB_TYPE}/database:${DB_VERSION} 
ARG DB_VERSION 
ARG DB_TYPE
ARG PASSWORD
RUN mkdir -p /opt/oracle/script
COPY --from=installer /opt/installer/target_script/* /opt/oracle/scripts/

每当它获取 docker 文件中的第二个 FROM 步骤时，它就会失败并出现错误invalid reference format，因为它无法识别获取图像的语法。

我的假设是它不知道如何处理ARG多阶段 docker 构建。

Answer 1

ARG 是有范围的。在第一个 FROM 行之前，它们是全局的并且仅在 FROM 行中可用。在每个阶段中，它们的范围都会限定到该阶段结束为止。所以你需要：

ARG DOCKER_REGISTRY=example.com/docker
# move the DB_VERSION and DB_TYPE above the first FROM line
ARG DB_VERSION 
ARG DB_TYPE
FROM $DOCKER_REGISTRY/openjdk8:latest AS installer 

# none of these args seem to do anything, unless you have
# ONBUILD steps that depend on them in your openjdk image
ARG APP_VERSION=6.3.0.78 
ARG DOCKER_REGISTRY 
ARG REPO_TYPE=snapshot 
ARG DB_VERSION=12.2.0.11-ee
ARG DB_TYPE=oracle ARG PASSWORD

FROM ${DOCKER_REGISTRY}/${DB_TYPE}/database:${DB_VERSION} 

# none of these args are used either
ARG DB_VERSION 
ARG DB_TYPE
ARG PASSWORD

RUN mkdir -p /opt/oracle/script
COPY --from=installer /opt/installer/target_script/* /opt/oracle/scripts/