Fix overriding of alpine builder

Makefile

@@ -37,20 +37,26 @@ build-builder-jammy: build-linux-packages build-sample-root
 build-linux-buildpacks: build-buildpacks-alpine build-buildpacks-jammy
 
 build-buildpacks-alpine: build-sample-root
+	@echo "> Starting local registry to store alpine builder (when builder contains extensions it must exist in a registry so that builds can use --pull-policy=always and we don't want to override the locally built builder)"
+	docker run -d --rm -p 5000:5000 registry:2
+	sleep 2
+	docker tag cnbs/sample-builder:alpine localhost:5000/cnbs/sample-builder:alpine
+	docker push localhost:5000/cnbs/sample-builder:alpine
+
 	@echo "> Creating 'hello-moon' app using 'alpine' builder..."
-	$(PACK_CMD) build sample-hello-moon-app:alpine -v --builder cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-world --buildpack $(SAMPLES_ROOT)/buildpacks/hello-moon $(PACK_BUILD_FLAGS)
+	$(PACK_CMD) build sample-hello-moon-app:alpine -v --builder localhost:5000/cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-world --buildpack $(SAMPLES_ROOT)/buildpacks/hello-moon --network=host
 
 	@echo "> Creating 'hello-processes' app using 'alpine' builder..."
-	$(PACK_CMD) build sample-hello-processes-app:alpine -v --builder cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-processes $(PACK_BUILD_FLAGS)
+	$(PACK_CMD) build sample-hello-processes-app:alpine -v --builder localhost:5000/cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-processes --network=host
 
 	@echo "> Creating 'hello-world' app using 'alpine' builder..."
-	$(PACK_CMD) build sample-hello-world-app:alpine -v --builder cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-world $(PACK_BUILD_FLAGS)
+	$(PACK_CMD) build sample-hello-world-app:alpine -v --builder localhost:5000/cnbs/sample-builder:alpine --buildpack $(SAMPLES_ROOT)/buildpacks/hello-world --network=host
 
 	@echo "> Creating 'java-maven' app using 'alpine' builder..."
-	$(PACK_CMD) build sample-java-maven-app:alpine -v --builder cnbs/sample-builder:alpine --path apps/java-maven $(PACK_BUILD_FLAGS)
+	$(PACK_CMD) build sample-java-maven-app:alpine -v --builder localhost:5000/cnbs/sample-builder:alpine --path apps/java-maven --network=host
 
 	@echo "> Creating 'kotlin-gradle' app using 'alpine' builder..."
-	$(PACK_CMD) build sample-kotlin-gradle-app:alpine -v --builder cnbs/sample-builder:alpine --path apps/kotlin-gradle $(PACK_BUILD_FLAGS)
+	$(PACK_CMD) build sample-kotlin-gradle-app:alpine -v --builder localhost:5000/cnbs/sample-builder:alpine --path apps/kotlin-gradle --network=host
 
 build-buildpacks-jammy: build-sample-root
 	@echo "> Creating 'hello-moon' app using 'jammy' builder..."

buildpacks/hello-extensions/bin/build

@@ -7,7 +7,7 @@ tree --version
 
 layers_dir=$1
 
-cat >> "${layers_dir}/launch.toml" <<EOL
+cat >>"${layers_dir}/launch.toml" <<EOL
 [[processes]]
 type = "curl"
 command = ["curl"]

buildpacks/hello-extensions/bin/detect

@@ -1,16 +1,25 @@
 #!/usr/bin/env bash
 set -eo pipefail
 
+if [[ -z "${BP_EXT_DEMO}" ]]; then
+  exit 100
+fi
+
 # 1. GET ARGS
 plan_path=$2
 
 # 2. DECLARE DEPENDENCIES (OPTIONAL)
-cat >> "${plan_path}" <<EOL
-# Uncomment first
-#[[requires]]
-#name = "tree"
 
-# Uncomment second
-#[[requires]]
-#name = "curl"
+if [[ "${BP_REQUIRES}" == *"tree"* ]]; then
+  cat >>"${plan_path}" <<EOL
+[[requires]]
+name = "tree"
+EOL
+fi
+
+if [[ "${BP_REQUIRES}" == *"curl"* ]]; then
+  cat >>"${plan_path}" <<EOL
+[[requires]]
+name = "curl"
 EOL
+fi