Enforce CRD CEL validation rules client-side in libcalico-go#11973
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caseydavenport merged 13 commits intomasterfrom Mar 17, 2026
Merged
Enforce CRD CEL validation rules client-side in libcalico-go#11973caseydavenport merged 13 commits intomasterfrom
caseydavenport merged 13 commits intomasterfrom
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Pull request overview
This PR adds client-side enforcement of CRD x-kubernetes-validations (CEL) within libcalico-go, so that resources are validated consistently in both Kubernetes datastore mode (API server enforces CEL) and etcd mode (no API server).
Changes:
- Integrates CEL validation into the existing
libcalico-go/lib/validator/v3.Validate()path and aggregates CEL + struct validation errors into a singleErrorValidation. - Introduces a new
libcalico-go/lib/validator/celpackage that compiles CEL programs from embedded CRD schemas and evaluates them against objects converted to unstructured form. - Adds unit/integration tests covering Tier CEL validation and combined (struct + CEL) error reporting.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.
| File | Description |
|---|---|
libcalico-go/lib/validator/v3/validator.go |
Runs CEL validation alongside existing validator.v9 struct validation and merges errors. |
libcalico-go/lib/validator/v3/cel_integration_test.go |
Verifies CEL is invoked through v3.Validate() and that errors are combined. |
libcalico-go/lib/validator/cel/cel.go |
Loads embedded CRDs, builds structural schemas, compiles CEL validators once, and validates objects. |
libcalico-go/lib/validator/cel/cel_test.go |
Tests CEL validator initialization and Tier CEL rule enforcement. |
Add a new cel validator package that compiles x-kubernetes-validations rules from embedded CRD schemas into Go-executable CEL programs at init time, using the K8s apiextensions-apiserver CEL libraries. Wire it into the existing v3 Validate() function so CEL rules are enforced regardless of datastore backend. In Kubernetes mode the API server already enforces these via CRDs, but in etcd mode there's no API server — so without this, CEL validations were simply not checked. Both Go struct validation errors and CEL errors are now collected and returned together in a single ErrorValidation.
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Overall seems good. Left a few comments and nits.
- Move CEL validation from separate cel package into validator/v3 as crd_validation.go - Add OpenAPI schema validation alongside CEL (enforces enum, minItems, maxLength, pattern, etc. from CRD schemas) - Find storage version instead of assuming Versions[0] - Infer Kind from Go type when TypeMeta isn't set - Use logrus directly instead of aliasing as log - Consolidate var block, use init() instead of sync.Once - Replace custom contains helpers with strings.Contains - Restructure tests as per-Kind top-level tests with shared crdTestCase runner
caseydavenport
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Mar 16, 2026
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Mar 16, 2026
3 tasks
The CEL rules for tier defaultAction were crashing with "no such key" when defaultAction wasn't set, because the field is omitempty. Add has() guards so missing values are properly rejected instead of causing a runtime error. Also move CRD loading from the legacy libcalico-go/config/crd/ embed to the canonical api/ module CRDs, which are the ones generated from the Go type annotations and always have up-to-date CEL rules. Update tier tests to set DefaultAction on well-known tiers and add negative test cases for wrong default actions.
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Removing "merge-when-ready" label due to new commits |
CRD schema validation now catches additional constraint violations (enum, maxLength) alongside Go struct validation, producing multi-field errors. The error format changes from "error with field X" (singular) to a bulleted list, breaking substring assertions. Strip the prefix so assertions match the field-specific content in both formats.
# Conflicts: # api/pkg/apis/projectcalico/v3/tier.go
- BGPPeer CEL: cast literal 0 to uint() for ASNumber (uint32) comparisons, fixing "expected int, got uint64" errors in CEL evaluation. - IPAMConfig test: use ContainSubstring instead of Equal since the error now includes both Go validator and CRD schema validation messages. - IP Pool controller test: add time.Sleep between pool creates to ensure distinct creation timestamps for deterministic sort ordering.
The CRD schema represents asNumber as int (not uint), so CEL comparisons must use int literals. The uint(0) cast caused CEL compilation failures.
Use JSON round-trip in toUnstructured() instead of runtime.DefaultUnstructuredConverter, which preserves Go types via reflection (e.g. uint32 → uint64). The API server receives JSON where numbers are float64/int64, so the converter must match that. Normalize float64 values to int64 where exact, fixing CEL runtime errors like "expected int, got uint64" for fields like numorstring.ASNumber. Add BGPPeer ASNumber CEL tests to cover this case.
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Description
Right now, CEL validation rules (
x-kubernetes-validations) on our CRDs are only enforced by the Kubernetes API server. In etcd mode there's no API server in the picture, so these validations are just silently skipped — which means you can create resources that violate the CEL rules without any error.This PR adds a new package
libcalico-go/lib/validator/cel/that compiles the CEL rules from our embedded CRD schemas into Go-executable validators at init time, using the K8sapiextensions-apiserverCEL libraries. The pipeline is roughly:config.AllCRDs()v1.JSONSchemaProps→ internal →structuralschema.Structuralcelvalidation.NewValidator()(returns nil for CRDs with no CEL rules)This is wired into the existing
v3.Validate()function, so both Go struct validation and CEL validation run together and errors from both are collected into a singleErrorValidation. CurrentlyTierandClusterNetworkPolicyare the only CRDs with CEL rules, but any futurex-kubernetes-validationswill automatically be picked up.Note: This is a prototype / proof-of-concept. A few things that could be improved in follow-ups:
oldSelf(the currentValidate()signature doesn't take an old object)