Problem Description
Here is the content of Dockerfile:
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FROM alpine
ADD . /app/
WORKDIR /app
RUN echo "hello world"
RUN ls -l
When using the new version of Docker to execute docker build, I found that the RUN command has no output.
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❯ docker build -t test -f Dockerfile .
[+] Building 1.0s (10/10) FINISHED
=> [internal] load build definition from Dockerfile 0.0s
=> => transferring dockerfile: 112B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/library/alpine:latest 0.0s
=> [internal] load build context 0.0s
=> => transferring context: 107B 0.0s
=> CACHED [1/5] FROM docker.io/library/alpine 0.0s
=> [2/5] ADD . /app/ 0.0s
=> [3/5] WORKDIR /app 0.0s
=> [4/5] RUN echo "hello world" 0.4s
=> [5/5] RUN ls -l 0.4s
=> exporting to image 0.1s
=> => exporting layers 0.0s
=> => writing image sha256:95911a7870dbd929ced4a031c65a180310a5480de759b19a5b08556cd443775b 0.0s
=> => naming to docker.io/library/test
This is very unfavorable for debugging when building images.
Solution
Add DOCKER_BUILDKIT=0 in front of the docker build command to print the command output like the previous Docker version.
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❯ DOCKER_BUILDKIT=0 docker build -t test -f Dockerfile .
Sending build context to Docker daemon 2.048kB
Step 1/5 : FROM alpine
---> 389fef711851
Step 2/5 : ADD . /app/
---> 34cccaf2b826
Step 3/5 : WORKDIR /app
---> Running in 65eefb594656
Removing intermediate container 65eefb594656
---> 07582a62e423
Step 4/5 : RUN echo "hello world"
---> Running in bcd94b080379
hello world
Removing intermediate container bcd94b080379
---> 6fbc11007cff
Step 5/5 : RUN ls -l
---> Running in 8d9423839270
total 4
-rw-r--r-- 1 root root 70 Apr 29 03:07 Dockerfile
Removing intermediate container 8d9423839270
---> 7b6aee767fab
Successfully built 7b6aee767fab
Successfully tagged test:latest
工具 - Docker build 执行命令（Dockerfile RUN）没有任何输出