do not patch Dockerfiles in CI

[thaJeztah]

When building the Dockerfiles for development, those images are mainly used to create a reproducible build-environment. The source code is bind-mounted into the image at runtime; there is no need to create an image with the actual source code, and copying the source code into the image would lead to a new image being created for each code-change (possibly leading up to many "dangling" images for previous code-changes).

However, when building (and using) the development images in CI, bind-mounting is not an option, because the daemon is running remotely.

To make this work, the circle-ci script patched the Dockerfiles when CI is run; adding a COPY to the respective Dockerfiles.

Patching Dockerfiles is not really a "best practice" and, even though the source code does not and up in the image, the source would still be sent to the daemon for each build (unless BuildKit is used).

This patch updates the makefiles, circle-ci script, and Dockerfiles;

• When building the Dockerfiles locally, pipe the Dockerfile through stdin.
  Doing so, prevents the build-context from being sent to the daemon. This speeds
  up the build, and doesn't fill up the Docker "temp" directory with content that's
  not used
• Now that no content is sent, add the COPY instructions to the Dockerfiles, and
  remove the code in the circle-ci script to "live patch" the Dockerfiles.

Before this patch is applied (with cache):

$ time make -f docker.Makefile build_shell_validate_image
docker build -t docker-cli-shell-validate -f ./dockerfiles/Dockerfile.shellcheck .
Sending build context to Docker daemon     41MB
Step 1/2 : FROM    debian:stretch-slim
...
Successfully built 81e14e8ad856
Successfully tagged docker-cli-shell-validate:latest

2.75 real         0.45 user         0.56 sys

After this patch is applied (with cache)::

$ time make -f docker.Makefile build_shell_validate_image
cat ./dockerfiles/Dockerfile.shellcheck | docker build -t docker-cli-shell-validate -
Sending build context to Docker daemon  2.048kB
Step 1/2 : FROM    debian:stretch-slim
...
Successfully built 81e14e8ad856
Successfully tagged docker-cli-shell-validate:latest

0.33 real         0.07 user         0.08 sys

Signed-off-by: Sebastiaan van Stijn [email protected]

- What I did

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- How to verify it

- Description for the changelog

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[thaJeztah]

ping @ijc @vdemeester @dnephin PTAL

[codecov-io]

Codecov Report

Merging #1537 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1537      +/-   ##
==========================================
- Coverage   55.22%   55.22%   -0.01%     
==========================================
  Files         289      289              
  Lines       19389    19384       -5     
==========================================
- Hits        10708    10705       -3     
+ Misses       7984     7983       -1     
+ Partials      697      696       -1

[vdemeester]

LGTM 🐯

[thaJeztah]

ping @silvin-lubecki @dnephin PTAL 🤗

[dnephin]

LGTM

Interesting solution to the problem. I agree it's an improvement over appending to the Dockerfile.

What I ended up doing in one of my projects to solve this same problem is to make the main image FROM ... as dev and then I added:

FROM dev as dev-with-source
COPY . .

Then I could use --target dev to get a version that still had some context, but not necessarily the full context.

[thaJeztah]

Yes, I considered that solution; the downside of that solution is that the context is still sent, even though it's not consumed. In this case, no context was needed at all, so I went for this option; the "FROM dev ..." approach could be used once we need it

…

On 1 Dec 2018, at 05:05, Daniel Nephin ***@***.***> wrote: @dnephin approved this pull request. LGTM Interesting solution to the problem. I agree it's an improvement over appending to the Dockerfile. What I ended up doing in one of my projects to solve this same problem is to make the main image FROM ... as dev and then I added: FROM dev as dev-with-source COPY . . Then I could use --target dev to get a version that still had some context, but not necessarily the full context. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or mute the thread.

[thaJeztah]

ready for merge? 🤗

[vdemeester]

LGTM 🐯