Support '/' and '-' in braced template placeholders

[zoispag]

Problem

Kubernetes label and annotation keys routinely contain / (the prefix separator) and - — for example app.kubernetes.io/name or com.example/job-count. However, ExtendedTemplate.idpattern in src/robusta/utils/parsing.py only allows [_a-z0-9.], so a placeholder like:

customPlaybooks:
- triggers:
  - on_pod_oom_killed: {}
  actions:
  - create_finding:
      title: "Pod $name OOMKilled while running job ${annotations.com.example/job-count}"
      aggregation_key: PodOOMKilled

never matches and is left verbatim in the rendered output of format_event_templated_string (used by create_finding, customise_finding, kubectl_command, foreign_logs_enricher, warning_events_report, krr args, …). This makes it impossible to reference most real-world label/annotation keys, since any key with a prefix or a hyphen is unmatchable.

Solution

Extend only the braced form (${...}) via string.Template's braceidpattern to additionally allow / and -:

braceidpattern = r"(?a:[_a-z][_a-z0-9./-]*)"

The unbraced idpattern is intentionally left untouched so existing templates like $name-suffix (where -suffix is literal text after the variable) keep their current behavior. This is fully backwards compatible: braced placeholders that matched before still match and resolve identically; the only new behavior is that previously-unmatchable keys now resolve.

Testing

Added tests/test_parsing.py covering format_event_templated_string: subject fields (braced and unbraced), label/annotation lookups with plain and prefixed keys (${labels.app.kubernetes.io/name}, ${annotations.com.example/job-count}), <missing> fallback, $$ escaping, and the unchanged $name-suffix unbraced behavior. The new slash/hyphen cases fail without the fix and pass with it; all 9 cases pass.

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ℹ️ Recent review info

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Reviewing files that changed from the base of the PR and between a6005eb and 5d15b91.

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• tests/test_parsing.py

🚧 Files skipped from review as they are similar to previous changes (1)

• tests/test_parsing.py

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Walkthrough

The PR broadens braced template placeholder identifiers by adding ExtendedTemplate.braceidpattern (allowing / and -) and adds parametrized tests verifying substitution for braced/unbraced placeholders, label/annotation lookups (including keys with / and -), missing-variable fallback, and escaped dollar handling.

Changes

Template Placeholder Enhancement

Layer / File(s)	Summary
Template placeholder pattern extension src/robusta/utils/parsing.py	ExtendedTemplate.braceidpattern regex is added to permit / and - characters in braced placeholder identifiers, extending which keys can be safely substituted by safe_substitute.
Template substitution test coverage tests/test_parsing.py	Parametrized test validates format_event_templated_string with subject field placeholders, braced and unbraced forms, label/annotation resolution via dot paths (including keys with / and -), fallback to "<missing>" for unknowns, and escaped dollar sign preservation.

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically summarizes the main change: extending braced template placeholders to support '/' and '-' characters in Kubernetes label/annotation keys.
Description check	✅ Passed	The description is well-related to the changeset, explaining the problem with Kubernetes label/annotation keys, the solution via braceidpattern extension, and the testing approach.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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