Feat selector transforms

examples/selector_with_transforms/README.md

@@ -0,0 +1,55 @@
+# Example manifests
+
+You can run your function locally and test it using `crossplane beta render`
+with these example manifests.
+
+This example demonstrates four different transform types on label selectors,
+each pulling from different fields of the composite resource:
+
+1. **Regexp group extract** — `spec.region` (`us-east-1-abc`) → capture group 1
+   → `us-east-1`
+2. **Regexp replace with backreferences** —
+   `metadata.labels[crossplane.io/claim-namespace]` (`team-alpha`) →
+   `${1}-environment-config` → `alpha-environment-config`
+3. **Map transform** — `spec.tier` (`production`) → mapped to `prod`
+4. **Convert to lowercase** — `spec.priority` (`CRITICAL`) → `critical`
+
+Together they select the EnvironmentConfig labeled `region: us-east-1`,
+`config: alpha-environment-config`, `tier: prod`, `priority: critical`.
+
+```shell
+# Run the function locally
+$ go run . --insecure --debug
+```
+
+```shell
+# Then, in another terminal, call it with these example manifests
+$ crossplane render \
+  --extra-resources selector_with_transforms/environmentConfigs.yaml \
+  --include-context \
+  selector_with_transforms/xr.yaml selector_with_transforms/composition.yaml selector_with_transforms/functions.yaml
+---
+apiVersion: example.crossplane.io/v1
+kind: XR
+metadata:
+  name: example-xr
+status:
+  conditions:
+  - lastTransitionTime: "2024-01-01T00:00:00Z"
+    reason: Available
+    status: "True"
+    type: Ready
+  fromEnv: https://us-east-1.example.com
+  team: alpha
+---
+apiVersion: render.crossplane.io/v1beta1
+fields:
+  apiextensions.crossplane.io/environment:
+    apiVersion: internal.crossplane.io/v1alpha1
+    kind: Environment
+    region:
+      endpoint: https://us-east-1.example.com
+      name: us-east-1
+    team: alpha
+kind: Context
+```

examples/selector_with_transforms/composition.yaml

@@ -0,0 +1,81 @@
+apiVersion: apiextensions.crossplane.io/v1
+kind: Composition
+metadata:
+  name: function-environment-configs
+spec:
+  compositeTypeRef:
+    apiVersion: example.crossplane.io/v1
+    kind: XR
+  mode: Pipeline
+  pipeline:
+  - step: environmentConfigs
+    functionRef:
+      name: function-environment-configs
+    input:
+      apiVersion: environmentconfigs.fn.crossplane.io/v1beta1
+      kind: Input
+      spec:
+        environmentConfigs:
+          - type: Selector
+            selector:
+              mode: Single
+              matchLabels:
+                # 1. Regexp group extract:
+                #    "us-east-1-abc" → extract group 1 → "us-east-1"
+                - key: region
+                  valueFromFieldPath: spec.region
+                  transforms:
+                    - type: string
+                      string:
+                        type: Regexp
+                        regexp:
+                          match: "^([^-]+-[^-]+-[0-9]+)"
+                          group: 1
+
+                # 2. Regexp replace with backreferences:
+                #    "team-alpha" → "${1}-environment-config" → "alpha-environment-config"
+                - key: config
+                  valueFromFieldPath: "metadata.labels[crossplane.io/claim-namespace]"
+                  transforms:
+                    - type: string
+                      string:
+                        type: Regexp
+                        regexp:
+                          match: "^team-(.+)$"
+                          replace: "${1}-environment-config"
+
+                # 3. Map transform:
+                #    "production" → "prod"
+                - key: tier
+                  valueFromFieldPath: spec.tier
+                  transforms:
+                    - type: map
+                      map:
+                        production: "prod"
+                        staging: "stage"
+                        development: "dev"
+
+                # 4. Convert to lowercase:
+                #    "CRITICAL" → "critical"
+                - key: priority
+                  valueFromFieldPath: spec.priority
+                  transforms:
+                    - type: string
+                      string:
+                        type: Convert
+                        convert: ToLower
+  - step: go-templating
+    functionRef:
+      name: function-go-templating
+    input:
+      apiVersion: gotemplating.fn.crossplane.io/v1beta1
+      kind: GoTemplate
+      source: Inline
+      inline:
+        template: |
+          ---
+          apiVersion: example.crossplane.io/v1
+          kind: XR
+          status:
+            fromEnv: {{ index .context "apiextensions.crossplane.io/environment" "region" "endpoint" }}
+            team: {{ index .context "apiextensions.crossplane.io/environment" "team" }}

examples/selector_with_transforms/environmentConfigs.yaml

@@ -0,0 +1,45 @@
+---
+apiVersion: apiextensions.crossplane.io/v1beta1
+kind: EnvironmentConfig
+metadata:
+  name: env-us-east-1-alpha-prod-critical
+  labels:
+    region: "us-east-1"
+    config: "alpha-environment-config"
+    tier: "prod"
+    priority: "critical"
+data:
+  region:
+    name: us-east-1
+    endpoint: https://us-east-1.example.com
+  team: alpha
+---
+apiVersion: apiextensions.crossplane.io/v1beta1
+kind: EnvironmentConfig
+metadata:
+  name: env-us-east-1-beta-prod-critical
+  labels:
+    region: "us-east-1"
+    config: "beta-environment-config"
+    tier: "prod"
+    priority: "critical"
+data:
+  region:
+    name: us-east-1
+    endpoint: https://us-east-1.example.com
+  team: beta
+---
+apiVersion: apiextensions.crossplane.io/v1beta1
+kind: EnvironmentConfig
+metadata:
+  name: env-eu-west-1-alpha-stage-low
+  labels:
+    region: "eu-west-1"
+    config: "alpha-environment-config"
+    tier: "stage"
+    priority: "low"
+data:
+  region:
+    name: eu-west-1
+    endpoint: https://eu-west-1.example.com
+  team: alpha

examples/selector_with_transforms/functions.yaml

@@ -0,0 +1,18 @@
+---
+apiVersion: pkg.crossplane.io/v1beta1
+kind: Function
+metadata:
+  name: function-environment-configs
+  annotations:
+    # This tells crossplane beta render to connect to the function locally.
+    render.crossplane.io/runtime: Development
+spec:
+  # This is ignored when using the Development runtime.
+  package: xpkg.upbound.io/crossplane-contrib/function-environment-configs:v0.4.0
+---
+apiVersion: pkg.crossplane.io/v1beta1
+kind: Function
+metadata:
+  name: function-go-templating
+spec:
+  package: xpkg.upbound.io/crossplane-contrib/function-go-templating:v0.10.0

examples/selector_with_transforms/provider.yaml

@@ -0,0 +1,8 @@
+---
+apiVersion: pkg.crossplane.io/v1
+kind: Provider
+metadata:
+  name: provider-nop
+spec:
+  package: xpkg.upbound.io/crossplane-contrib/provider-nop:v0.4.0
+  ignoreCrossplaneConstraints: true

examples/selector_with_transforms/xr.yaml

@@ -0,0 +1,10 @@
+apiVersion: example.crossplane.io/v1
+kind: XR
+metadata:
+  name: example-xr
+  labels:
+    crossplane.io/claim-namespace: team-alpha
+spec:
+  region: us-east-1-abc
+  tier: production
+  priority: CRITICAL

examples/selector_with_transforms/xrd.yaml

@@ -0,0 +1,36 @@
+---
+apiVersion: apiextensions.crossplane.io/v1
+kind: CompositeResourceDefinition
+metadata:
+  name: xrs.example.crossplane.io
+spec:
+  group: example.crossplane.io
+  names:
+    kind: XR
+    plural: xrs
+  connectionSecretKeys:
+    - test
+  versions:
+    - name: v1
+      served: true
+      referenceable: true
+      schema:
+        openAPIV3Schema:
+          type: object
+          properties:
+            spec:
+              type: object
+              properties:
+                region:
+                  type: string
+                tier:
+                  type: string
+                priority:
+                  type: string
+            status:
+              type: object
+              properties:
+                fromEnv:
+                  type: string
+                team:
+                  type: string

fn.go

@@ -7,20 +7,18 @@ import (
 	"reflect"
 	"sort"
 
-	"google.golang.org/protobuf/types/known/structpb"
-	extv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
-	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
-	"k8s.io/apimachinery/pkg/runtime/schema"
-
+	"github.com/crossplane-contrib/function-environment-configs/input/v1beta1"
 	"github.com/crossplane/crossplane-runtime/pkg/errors"
 	"github.com/crossplane/crossplane-runtime/pkg/fieldpath"
 	"github.com/crossplane/crossplane-runtime/pkg/logging"
 	fnv1 "github.com/crossplane/function-sdk-go/proto/v1"
 	"github.com/crossplane/function-sdk-go/request"
 	"github.com/crossplane/function-sdk-go/resource"
 	"github.com/crossplane/function-sdk-go/response"
-
-	"github.com/crossplane-contrib/function-environment-configs/input/v1beta1"
+	"google.golang.org/protobuf/types/known/structpb"
+	extv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
 )
 
 const (
@@ -304,14 +302,22 @@ func buildRequirements(in *v1beta1.Input, xr *resource.Composite) (*fnv1.Require
 					// TODO validate value not to be nil
 					matchLabels[selector.Key] = *selector.Value
 				case v1beta1.EnvironmentSourceSelectorLabelMatcherTypeFromCompositeFieldPath:
-					value, err := fieldpath.Pave(xr.Resource.Object).GetString(*selector.ValueFromFieldPath)
+					val, err := fieldpath.Pave(xr.Resource.Object).GetValue(*selector.ValueFromFieldPath)
 					if err != nil {
 						if !selector.FromFieldPathIsOptional() {
 							return nil, errors.Wrapf(err, "cannot get value from field path %q", *selector.ValueFromFieldPath)
 						}
 						continue
 					}
-					matchLabels[selector.Key] = value
+					// Apply transforms if any are specified.
+					if len(selector.Transforms) > 0 {
+						val, err = ResolveTransforms(selector.Transforms, val)
+						if err != nil {
+							return nil, errors.Wrapf(err, "cannot apply transforms for label %q from field path %q", selector.Key, *selector.ValueFromFieldPath)
+						}
+					}
+					// Labels are always strings.
+					matchLabels[selector.Key] = fmt.Sprintf("%v", val)
 				}
 			}
 			if len(matchLabels) == 0 {