chore(docker): improve debian Dockerfile structure and optimize base image setup

[rauldsl]

What type of PR is this?

/kind cleanup
/kind bug

Any specific area of the project related to this PR?

/area build

What this PR does / why we need it:

This PR removes duplicated package installation blocks inside the Falcon Dockerfile and centralizes environment variables into a single, consistent location.

Which issue(s) this PR fixes:

Fixes #
(If there is no issue linked, leave it empty or remove the line.)

Special notes for your reviewer:

The modifications do not introduce functional changes to Falco’s behavior; they strictly improve the Dockerfile structure and maintainability.
All duplicated package sections were consolidated without altering execution order or runtime behavior.

Does this PR introduce a user-facing change?:

NONE

[poiana]

Welcome @rauldsl! It looks like this is your first PR to falcosecurity/falco 🎉

[rauldsl]

Release note:

Dockerfile improvements

[leogr]

Hey @rauldsl

Thanks for this PR. Out of curiosity, may I ask why you didn't use the default PR template and used a custom one?

[rauldsl]

Hey @rauldsl

Thanks for this PR. Out of curiosity, may I ask why you didn't use the default PR template and used a custom one?

@leogr
First of, Sorry for the confusion.
I’m new to the repository, and I accidentally copied the wrong content from my clipboard, it was something I was using in another repo. My apologies for that. I’ve now updated it with the correct content

[rauldsl]

@leogr Is anything pending on my end regarding this PR?

[leogr]

@leogr Is anything pending on my end regarding this PR?

Yes, the comments I left above are not actually resolved ( #3738 (review) ).

We need FALCO_VERSION to be an argument, not computed in the Dockerfile.

[leogr]

@leogr Is anything pending on my end regarding this PR?

Yes, the comments I left above are not actually resolved ( #3738 (review) ).

We need FALCO_VERSION to be an argument, not computed in the Dockerfile.

@rauldsl any update on this?

[rauldsl]

@leogr Is anything pending on my end regarding this PR?

Yes, the comments I left above are not actually resolved ( #3738 (review) ).
We need FALCO_VERSION to be an argument, not computed in the Dockerfile.

@rauldsl any update on this?

Done, as you requested.

[leogr]

/release-note-none

[Copilot]

Pull request overview

This PR refactors three Dockerfiles to improve structure and maintainability by consolidating environment variable declarations and removing duplicate package installations. The changes are primarily organizational with the goal of improving code clarity without altering runtime behavior.

Key Changes

• Consolidated multiple ENV declarations into single multi-line ENV statements with proper quoting
• Converted some hardcoded values to ARG variables for better parameterization
• Optimized package installation commands by removing duplicates (e.g., ca-certificates in falco-debian)

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
docker/falco/Dockerfile	Consolidated ENV declarations, added ARG variables for HOST_ROOT and HOME, optimized download logic with ARCH variable, and added URL-encoded version handling
docker/falco-debian/Dockerfile	Consolidated ENV declarations, added ARG variables for configuration values, added DEBIAN_FRONTEND setting, and removed duplicate ca-certificates package
docker/driver-loader-buster/Dockerfile	Consolidated ENV declarations into a single multi-line statement with proper quoting

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[leogr]

In addition to CoPilot's findings, I have added some minor fixes.
IMO, these are the missing changes required before approving this PR.

[poiana]

LGTM label has been added.

Details

Git tree hash: 0b2299e167d50a730bc972b1c2b7155797d6d12e

[irozzo-1A]

/lgtm

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: irozzo-1A, rauldsl, sgaist

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• docker/OWNERS [sgaist]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ekoops]

I left a comment!

[ekoops]

Please don't set DEBIAN_FRONTEND as environment variable, as this will persist at runtime. If you want to use it, you can inline it in the apt command.