Docker构建ARG始终为空字符串 [英] Docker build ARG always empty string

问题描述

我在这里有一个dockerfile:

I have a dockerfile here:

FROM golang:1.13-alpine as build
ARG DIR=somevalue
RUN echo $DIR

输出为

Sending build context to Docker daemon  57.37MB
Step 1/3 : FROM golang:1.13-alpine as build
 ---> 2e384b27f926
Step 2/3 : ARG DIR=somevalue
 ---> Running in 3cd3457a795f
Removing intermediate container 3cd3457a795f
 ---> ecfa2f50c4fa
Step 3/3 : RUN echo $DIR
 ---> Running in aab4e31e0e14

Removing intermediate container aab4e31e0e14
 ---> 5351cb77c245
Successfully built 5351cb77c245

当我尝试将DIR换为另一个名称示例DIR1时，DIR始终为空.Docker版本在这里

DIR is always empty when I try DIR to another name example DIR1 it is empty too. Docker version is here

 Client:

 Version:           18.09.8
 API version:       1.39
 Go version:        go1.11
 Git commit:        2c0a67b
 Built:             Fri Sep  6 02:50:44 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server:

 Engine:
  Version:          18.09.6
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.11
  Git commit:       1d8275b
  Built:            Fri Sep  6 02:51:05 2019
  OS/Arch:          linux/amd64
  Experimental:     false

但是，当我尝试使用另一台机器时，它是正确的，它将回显一些值.谁能给我一些提示，以查找有关错误机器的问题?谢谢.

However, when I try to another machine, it is right, it will echo some value. Who can give me some tips to find the problem about the wrong machine? thanks.

推荐答案

可以通过传递-no-cache 选项尝试运行，对我来说它按预期运行

Can you try running by passing the --no-cache option, it is working as expected for me

❯❯❯ docker build . --no-cache
Sending build context to Docker daemon  194.7MB
Step 1/3 : FROM golang:1.13-alpine as build
 ---> 2e384b27f926
Step 2/3 : ARG DIR=somevalue
 ---> Running in c53bbb64dda1
Removing intermediate container c53bbb64dda1
 ---> b76b21aca433
Step 3/3 : RUN echo $DIR
 ---> Running in 6c49d289e258
somevalue
Removing intermediate container 6c49d289e258
 ---> d51e5579f1cb
Successfully built d51e5579f1cb

但是，如果它曾经构建过一次相同的图像，则由于已缓存了该图层，因此不会输出任何内容:

However, if it has built the same image once, it will not output anything as it has the layer cached:

❯❯❯ docker build .
Sending build context to Docker daemon  194.7MB
Step 1/3 : FROM golang:1.13-alpine as build
 ---> 2e384b27f926
Step 2/3 : ARG DIR=somevalue
 ---> Using cache
 ---> b76b21aca433
Step 3/3 : RUN echo $DIR
 ---> Using cache
 ---> d51e5579f1cb
Successfully built d51e5579f1cb

这篇关于Docker构建ARG始终为空字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！