Is there any way to using hadolint for multiple dockerfiles? - docker

Question

Hadolint is an awesome tool for linting Dockerfiles. I am trying
to integrated to my CI but I am dealing with for run over multiple Dockerfiles. Does someone know how the syntax look like? Here is how my dirs appears to:
dir1/Dockerfile
dir2/Dockerfile
dir3/foo/Dockerfile
in gitlab-ci
stage: hadolint
image: hadolint/hadolint:latest-debian
script:
- mkdir -p reports
- |
hadolint dir1/Dockerfile > reports/dir1.json \
hadolint dir2/Dockerfile > reports/dir2.json \
hadolint dir3/foo/Dockerfile > reports/dir3.json
But the sample above is now working.

Answer 1

So as far as I found it, hadolint runs recursively. So in my case:
- hadolint */Dockerfile > reports/all_reports.json
But the problem with this approach is that all reports will be in one file which humper the maintenance and clarity

Answer 2

If you want to keep all reports separated (one per top-level directory), you may want to rely on some shell snippet?
I mean something like:
- |
find . -name Dockerfile -exec \
sh -c 'src=${1#./} && { set -x && hadolint "$1"; } | tee -a "reports/${src%%/*}.txt"' sh "{}" \;
Explanation:
find . -name Dockerfile loops over all Dockerfiles in the current directory;
-exec sh -c '…' runs a subshell for each Dockerfile, setting:
$0 = "sh" (dummy value)
$1 = "{}" (the full, relative path of the Dockerfile), "{}" and \; being directly related to the find … -exec pattern;
src=${1#./} trims the path, replacing ./dir1/Dockerfile with dir1/Dockerfile
${src%%/*} extracts the top-level directory name (dir1/Dockerfile → dir1)
and | tee -a … copies the output, appending hadolint's output to the top-level directory report file, for each parsed Dockerfile (while > … should be avoided here for obvious reasons, if you have several Dockerfiles in a single top-level directory).
I have replaced the .json extension with .txt as hadolint does not seem to output JSON data.