community VS hadolint

A list of adopters (many of which are hosting providers) is here: https://github.com/buildpacks/community/blob/main/ADOPTERS.m...

Many comments here point out how difficult it is to manage a separate dependency stack for each container when you use Dockerfiles to build them. This problem is just as difficult, time-intensive, and security-critical for microservice apps running on K8s as it is for CLI tools and graphical apps.

Worth pointing out that there is an incubating CNCF project that tries to solve this problem by forgoing Dockerfiles entirely: Cloud Native Buildpacks (https://buildpacks.io)

CNB defines safe seams between OCI image layers so that can be replaced out of order, directly on any Docker registry (only JSON requests), and en-mass. This means you can, e.g., instantly update all of your OS packages for your 1000+ containers without running any builds, as long as you use an LTS distribution with strong ABI promises (e.g., Ubuntu 20.04). Most major cloud vendors have quietly adopted it, especially for function builds: https://github.com/buildpacks/community/blob/main/ADOPTERS.m...

You might recognize "buildpacks" from Heroku, and in fact the project was started several years ago in the CNCF by the folks who maintained the Heroku and Cloud Foundry buildpacks in the pre-Dockerfile era.

[Disclaimer: I'm one of the founders of the project, on the VMware (formerly Cloud Foundry) side.]

3. Hadolint: https://github.com/hadolint/hadolint Hadolint is a Dockerfile linter that helps you build best practice Docker images, reducing vulnerabilities in your container configurations.

To skip the "move your scripts to standalone files" step some devs don't like, consider something like https://github.com/hadolint/hadolint which runs Shellcheck over inline scripts within Containerfiles.

This is neat :)

I love going and making containers smaller and faster to build.

I don't know if it's useful for alpine, but adding a --mount=type=cache argument to the RUN command that `apk add`s might shave a few seconds off rebuilds. Probably not worth it, in your case, unless you're invalidating the cached layer often (adding or removing deps, intentionally building without layer caching to ensure you have the latest packages).

Hadolint is another tool worth checking out if you like spending time messing with Dockerfiles: https://github.com/hadolint/hadolint

With Depot, we make use of two Dockerfile linters, hadolint and a set of Dockerfile linter rules that Semgrep has written to make a bit of a smarter Dockerfile linter.

# Download hadolint wget https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Linux-x86_64 # Download SHA256 checksum wget https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Linux-x86_64.sha256 # Validate the checksum sha256sum -c hadolint-Linux-x86_64.sha256 # Make the file executable chmod + ./hadolint-Linux-x86_64 # Rename the file mv hadolint-Linux-x86_64 hadolint

The most common linter I've seen and used it Hadolint, which does: https://github.com/hadolint/hadolint/wiki/DL3002 I didn't bother checking to see if alternatives also support this as well though.

Some discussion on that here:

https://github.com/koalaman/shellcheck/issues/58

The hadolint project does shell checking for Dockerfiles and it uses shellcheck:

https://github.com/hadolint/hadolint

So the approach is definitely feasible, but you do need a new project and probably it needs to be written in Haskell.

how does this compare to something like hadolint?