updateconfig: Add ACL support for ConfigMap updates

[midnightconman]

This enhancement adds Access Control List (ACL) functionality to the updateconfig plugin, allowing administrators to control which organizations and repositories can trigger ConfigMap updates.

New Features

• AllowedRepos: A list of org or org/repo entries that are permitted to update a configmap. If specified, only PRs from these sources will trigger updates. When empty, all repos are allowed (unless explicitly denied).

• DeniedRepos: A list of org or org/repo entries that are blocked from updating a configmap. Deny rules take precedence over allow rules.

Configuration Format

Entries can be specified in two formats:

• Org-level: "kubernetes" (matches all repos in the kubernetes org)
• Repo-level: "kubernetes/test-infra" (matches only this specific repo)

Example configuration:

config_updater:
  maps:
    prow/config.yaml:
      name: config
      allowed_repos:
        - kubernetes           # Allow entire org
        - istio/istio          # Allow specific repo
      denied_repos:
        - kubernetes/fork      # Block specific repo within allowed org

ACL Precedence Rules

1. If repo is in denied list (exact match) → denied
2. If org is in denied list → denied
3. If allow lists exist, repo must match an allowed entry
4. If no allow lists specified → allowed (unless denied above)

Implementation Details

• Added AllowedRepos and DeniedRepos fields to ConfigMapSpec
• Added IsAllowed(repo string) bool method to ConfigMapSpec
• Updated FilterChanges to accept repo parameter and filter updates
• Updated config-bootstrapper to pass empty repo (bypasses ACL checks)
• Uses config.SplitRepoName for org/repo parsing

Testing

• Added TestConfigMapSpecIsAllowed with 14 test cases covering:

  • No ACLs configured
  • Org-level and repo-level allow/deny entries
  • Mixed org and org/repo entries
  • Deny precedence over allow
  • Empty repo handling for config-bootstrapper

• Added TestFilterChangesWithACLs with 7 test cases covering:

  • End-to-end filtering with various ACL configurations
  • Multiple configmaps with different ACLs

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[k8s-ci-robot]

Hi @midnightconman. Thanks for your PR.

I'm waiting for a github.com member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: midnightconman
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Needs approval from an approver in each of these files:

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[Prucek]

I would like this not to be a breaking change, so I would like to see a passing test, when the config-updater uses the old version of the config, without AllowedRepos and DeniedRepos.

[midnightconman]

@Prucek Sounds good to me 👍 Can you add /ok-to-test, so we can test that?

[petr-muller]

/ok-to-test