feat: Sigma rules - #196
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Co-authored-by: Copilot <copilot@github.com>
MichaelThamm
changed the title
* feat: log files ignored due to unrecognized suffix in _multi_suffix_glob When rule files are skipped because they don't carry a recognized suffix (.rule, .rules, .yml, .yaml), emit an info-level log so operators can understand why their files are being silently ignored. Closes canonical/cos-configuration-k8s-operator#129 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * bump version * fix: replace deprecated urlopen capath with ssl.SSLContext; bump to 1.9.2 cafile/capath/cadefault params were removed in Python 3.13. Build an SSLContext from the cert path and pass it via the context= param instead. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * test: add unit tests for LokiEmitter._send_request cert handling Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * test: verify _multi_suffix_glob logs files with unrecognized suffixes Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> * style: wrap long line in test to satisfy black Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com> --------- Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
MichaelThamm
commented
Jun 25, 2026
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| Unlike Prometheus/Loki rules, Sigma rules are independent (no grouping concept): | ||
| detection logic lives in a ``detection`` block instead of an ``expr`` field. A rule | ||
| may carry an ``id`` (UUID) for reference, but it is optional and not enforced here as |
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Make sure to be careful with UUID since it can cause many relation-changed events. Ask Luca for details.
MichaelThamm
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Jun 25, 2026
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Revert this change
MichaelThamm
commented
Jun 25, 2026
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| # --- Free functions for file I/O, reusable across rule backends --- # | ||
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| _RULE_FILE_SUFFIXES = [".rule", ".rules", ".yml", ".yaml"] |
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Make sure that this works with Sigma rules. I think this is all-encompasing, but Sigma should filter to only YAML.
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Signed-off-by: Michael Thamm <mike.thamm@canonical.com>
MichaelThamm
commented
Jun 26, 2026
| def test_existing_juju_model_uuid_tag_not_overwritten(sigma): | ||
| sigma.add(_rule("Upstream UUID", tags=["juju_model_uuid.deadbeef"])) | ||
| tags = sigma.rules[0]["tags"] | ||
| assert "juju_model_uuid.deadbeef" in tags |
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update name deadbeef
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Issue
We need a Sigma rules feature in cos-lib to unblock these PRs:
Solution
What
Introduces a
SigmaRulesutility and the supporting type definitions so downstream charm libraries (e.g.charmlibs.interfaces.otlp) can aggregate and forward Sigma detection rules with Juju topology, the same wayAlertRules/RecordingRuleshandle PromQL/LogQL.SigmaRules(src/cosl/rules.py)add(rule_dict)— accepts a single Sigma rule or a{"rules": [...]}collection; skips entries missing required fields.add_path(dir_path, *, recursive=False)— aggregates rule files (.rule/.rules/.yml/.yaml) from a file or directory.as_dict()— returns the collection inSigmaRuleFileFormat.tagsasnamespace.value(e.g.juju_model.foo):juju_*tags win),relation-changedchurn),Unlike PromQL/LogQL, Sigma rules have no grouping/
exprconcept, so there is no expression rewriting — onlytagsenrichment.Types (
src/cosl/types.py)TypedDicts:SigmaRuleLogSource,SigmaRuleFormat,SigmaRuleFileFormat.Tests
tests/test_rules_sigma.py(348 lines) covering add/add_path/as_dict, topology injection precedence, deterministic tag ordering, and idempotent re-injection.tests/sigma_rules/(single rules + a collection).Notes
AlertRules/RecordingRulesbehavior.Checklist
project.versionfield in thepyproject.tomlfile.Context
Testing Instructions
Upgrade Notes