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nic-add-feature

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Checklists for adding Ingress annotations, VirtualServer/VSR fields, or Helm chart values to NIC. Use when adding new configuration options, new NGINX directives, new annotations, new CRD fields, or new Helm values.

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Source SKILL.md: https://github.com/nginx/kubernetes-ingress/blob/HEAD/.github/skills/nic-add-feature/SKILL.md

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Adding Features to NIC

Adding a New Annotation (Ingress Only)

Annotations apply ONLY to Ingress objects, never to VirtualServer or VirtualServerRoute.

  1. Add constant in internal/configs/annotations.go (e.g., MyAnnotation = "nginx.org/my-annotation")
  2. Add field to ConfigParams in internal/configs/config_params.go
  3. Parse it in parseAnnotations() in internal/configs/annotations.go
  4. Update masterDenylist / minionDenylist if it should not be on master/minion
  5. Apply it in generateNginxCfg() in internal/configs/ingress.go
  6. Add the NGINX directive in internal/configs/version1/nginx.ingress.tmpl and internal/configs/version1/nginx-plus.ingress.tmpl
  7. Add validation in internal/k8s/validation.go annotation validation chains
  8. Add tests in annotations_test.go and ingress_test.go

Gotchas

  • Never forget both OSS and Plus templates -- they are separate files
  • Use containsDangerousChars() for any user-provided string that ends up in NGINX config
  • parseAnnotations() silently ignores unknown annotations -- add the constant first

Adding a New VirtualServer/VSR Field

  1. Add field to the appropriate struct in pkg/apis/configuration/v1/types.go with kubebuilder markers
  2. Run make update-codegen and make update-crds
  3. Add validation in pkg/apis/configuration/validation/virtualserver.go
  4. Add to the version2 template struct in internal/configs/version2/http.go
  5. Wire in internal/configs/virtualserver.go (GenerateVirtualServerConfig or helper)
  6. Add template rendering in nginx.virtualserver.tmpl / nginx-plus.virtualserver.tmpl
  7. Update snapshot tests and run make test-update-snaps

JSON Tag Conventions

  • NGINX-proxy-related fields: kebab-case (json:"lb-method", json:"fail-timeout")
  • K8s/application fields: camelCase (json:"ingressClassName", json:"rewritePath")

Pointer vs Value Types

  • *int, *bool, *SomeStruct = optional/nullable
  • Plain int, bool = required or zero-value default
  • Booleans defaulting to false must be non-pointer

Kubebuilder Markers

MarkerPurpose
+kubebuilder:validation:RequiredField must be present
+kubebuilder:validation:OptionalField is optional
+kubebuilder:validation:Pattern= `regex`Regex validation
+kubebuilder:validation:Minimum=NNumeric minimum
+kubebuilder:validation:MinItems=N / MaxItems=NArray length
+kubebuilder:validation:MaxLength=NMax string length
+kubebuilder:default=valueDefault value
+kubebuilder:validation:XValidation:rule="CEL"Cross-field CEL validation

CEL Validation Examples

// Prevent wildcard origin with credentials
// +kubebuilder:validation:XValidation:rule="!(self.allowOrigin.exists(origin, origin == '*') && has(self.allowCredentials) && self.allowCredentials == true)",message="..."

// Require time when allowedCodes is set
// +kubebuilder:validation:XValidation:rule="!has(self.allowedCodes) || (has(self.allowedCodes) && has(self.time))",message="..."

Gotchas

  • Never skip make update-codegen after changing types.go
  • Never edit zz_generated.deepcopy.go manually
  • Version 2 has a single Server block; Version 1 has multiple Server blocks

Adding a Helm Chart Value

  1. Add to charts/nginx-ingress/values.yaml with ## documentation above the field
  2. Add JSON schema in charts/nginx-ingress/values.schema.json
  3. If it maps to a CLI arg: add to nginx-ingress.args in charts/nginx-ingress/templates/_helpers.tpl
  4. If it maps to a ConfigMap key: add to charts/nginx-ingress/templates/controller-configmap.yaml
  5. If it needs volumes/mounts: add to the volume helpers in _helpers.tpl
  6. Create a testdata file in charts/tests/testdata/<feature>.yaml
  7. Add test case in charts/tests/helmunit_test.go
  8. Run make test-update-snaps to capture the new snapshot

Gotchas

  • Always update all three workload templates (deployment, daemonset, statefulset) when they share logic via helpers
  • Always update values.schema.json alongside values.yaml
  • Helm tests use terratest + go-snaps: charts/tests/helmunit_test.go