Add skaffold-based dev setup

Makefile

@@ -103,3 +103,21 @@ verify: check format test
 
 .PHONY: verify-extended
 verify-extended: check-generate check format test
+
+#####################################################################
+# Rules for local environment                                       #
+#####################################################################
+
+# speed-up skaffold deployments by building all images concurrently
+extension-%: export SKAFFOLD_BUILD_CONCURRENCY = 0
+extension-%: export SKAFFOLD_DEFAULT_REPO = localhost:5001
+extension-%: export SKAFFOLD_PUSH = true
+# use static label for skaffold to prevent rolling all gardener components on every `skaffold` invocation
+extension-%: export SKAFFOLD_LABEL = skaffold.dev/run-id=shoot-flux
+
+extension-up: $(SKAFFOLD)
+	$(SKAFFOLD) run
+extension-dev: $(SKAFFOLD)
+	$(SKAFFOLD) dev --cleanup=false --trigger=manual
+extension-down: $(SKAFFOLD)
+	$(SKAFFOLD) delete

deploy/extension/local/kustomization.yaml

@@ -0,0 +1,8 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+- ../base
+
+patchesStrategicMerge:
+- patch-controller-deployment.yaml

deploy/extension/local/patch-controller-deployment.yaml

@@ -0,0 +1,7 @@
+apiVersion: core.gardener.cloud/v1beta1
+kind: ControllerRegistration
+metadata:
+  name: shoot-flux
+spec:
+  deployment:
+    policy: Always

skaffold.yaml

@@ -0,0 +1,21 @@
+---
+apiVersion: skaffold/v4beta3
+kind: Config
+metadata:
+  name: extension
+build:
+  artifacts:
+  - image: ghcr.io/stackitcloud/gardener-extension-shoot-flux
+    ko:
+      main: ./cmd/gardener-extension-shoot-flux
+resourceSelector:
+  allow:
+  # instruct skaffold to inject the built image reference into the image field in our ControllerDeployment
+  - groupKind: ControllerDeployment.core.gardener.cloud
+    image: [".*"]
+manifests:
+  kustomize:
+    paths:
+    - ./deploy/extension/local
+deploy:
+  kubectl: {}