SANDBOX-1561 | feature: debug builds for the host operator

build/Dockerfile

@@ -1,7 +1,12 @@
-FROM registry.access.redhat.com/ubi8/ubi-minimal:latest
+# Define the default build as "prod", so that in the case that no build
+# arguments are provided, we build the optimized image.
+ARG BUILD_TYPE='prod'
 
-LABEL maintainer "KubeSaw <devsandbox@redhat.com>"
-LABEL author "KubeSaw <devsandbox@redhat.com>"
+# Default production build steps for the operator.
+FROM registry.access.redhat.com/ubi8/ubi-minimal:latest AS prod-build
+
+LABEL maintainer="KubeSaw <devsandbox@redhat.com>"
+LABEL author="KubeSaw <devsandbox@redhat.com>"
 
 ENV OPERATOR=/usr/local/bin/host-operator \
     USER_UID=1001 \
@@ -16,4 +21,47 @@
 
 ENTRYPOINT ["/usr/local/bin/entrypoint"]
 
+# A throwaway intermediate path which compiles Delve with the same Golang
+# version as the host computer. That ensures no discrepancies in the code
+# when setting up breakpoints when debugging.
+FROM registry.access.redhat.com/ubi8/ubi-minimal:latest AS debug-initial-build
+
+# In this build path, the Golang version must be provided as a build argument,
+# which will ensure that Delve gets built with the same version the operator's
+# binary gets built with, to avoid any discrepancies.
+ARG GOLANG_VERSION
+RUN test -n "${GOLANG_VERSION}" || (echo 'The GOLANG_VERSION build parameter is required to build the debug image. Please provide it with "--build-arg GOLANG_VERSION=goX.Y.Z"' && exit 1)
+
+# Install the tools to be able to download and extract Golang.
+RUN microdnf install --assumeyes \
+    curl \
+    gzip \
+    tar \
+    && microdnf clean all
+
+# The target architecture in which the binary will be built.
+ARG TARGET_ARCH='linux-amd64'
+
+# Download and extract Golang.
+RUN curl --location --output "/tmp/${GOLANG_VERSION}.${TARGET_ARCH}.tar.gz" "https://go.dev/dl/${GOLANG_VERSION}.${TARGET_ARCH}.tar.gz" \
+    && tar --directory /usr/local --extract --file "/tmp/${GOLANG_VERSION}.${TARGET_ARCH}.tar.gz" \
+    && rm --force "/tmp/${GOLANG_VERSION}.${TARGET_ARCH}.tar.gz"
+
+# Put Golang in the path so that we can compile Delve with it.
+ENV PATH=$PATH:/usr/local/go/bin
+
+# Build Delve and leave it in a temporary directory.
+RUN GOBIN=/tmp/bin go install github.com/go-delve/delve/cmd/dlv@latest
+
+# In the case that the "BUILD_TYPE=debug" build argument is provided, we
+# "attempt to copy" the Delve executable into the production image. Since that
+# creates a dependency with the "debug-initial-build", that path is executed
+# by building the Delve executable.
+FROM prod-build AS debug-build
+COPY --from=debug-initial-build /tmp/bin/dlv /usr/local/bin/dlv
+
+# When the no build argument is provided, we simply fall back to the
+# production build which comes with the optimized and minimized image.
+FROM ${BUILD_TYPE}-build AS final-build
+
 USER ${USER_UID}

controllers/toolchainconfig/env.go

@@ -1,3 +1,6 @@
 package toolchainconfig
 
-const RegistrationServiceImageEnvKey = "REGISTRATION_SERVICE_IMAGE"
+const (
+	RegistrationServiceImageEnvKey   = "REGISTRATION_SERVICE_IMAGE"
+	RegistrationServiceCommandEnvKey = "REGISTRATION_SERVICE_COMMAND"
+)

controllers/toolchainconfig/toolchainconfig_controller.go

@@ -151,6 +151,16 @@ func getVars(namespace string, cfg ToolchainConfig) templateVars {
 	vars["IMAGE"] = image
 	vars.addIfNotEmpty("NAMESPACE", namespace)
 	vars.addIfNotEmpty("REPLICAS", fmt.Sprint(cfg.RegistrationService().Replicas()))
+
+	// Allow overriding the registration service's command via an environment
+	// variable.
+	command := os.Getenv(RegistrationServiceCommandEnvKey)
+	if command != "" {
+		vars["REGISTRATION_SERVICE_COMMAND"] = command
+	} else {
+		vars["REGISTRATION_SERVICE_COMMAND"] = `["registration-service"]`
+	}
+
 	return vars
 }
 

deploy/templates/registration-service/registration-service.yaml

@@ -96,13 +96,12 @@ objects:
               image: ${IMAGE}
               ports:
                 - containerPort: 8080 # registration service
-                - containerPort: 8081 # proxy 
+                - containerPort: 8081 # proxy
                 - containerPort: 8082 # proxy metrics
                   name: metrics
                 - containerPort: 8083 # registration service metrics
                   name: regsvc-metrics
-              command:
-                - registration-service
+              command: ${{REGISTRATION_SERVICE_COMMAND}}
               imagePullPolicy: IfNotPresent
               livenessProbe:
                 failureThreshold: 3
@@ -141,7 +140,7 @@ objects:
                 requests:
                   cpu: "50m"
                   memory: "100M"
-  
+
   # route for the registration service
   - kind: Route
     apiVersion: v1
@@ -202,7 +201,7 @@ objects:
         run: registration-service
       type: ClusterIP
       sessionAffinity: null
-  
+
   # route for the proxy
   - kind: Route
     apiVersion: v1
@@ -224,7 +223,7 @@ objects:
       tls:
         termination: edge
       wildcardPolicy: None
- 
+
   # service associated with the proxy route
   - kind: Service
     apiVersion: v1
@@ -244,7 +243,7 @@ objects:
         run: registration-service
       type: ClusterIP
       sessionAffinity: null
-  
+
   # internal service for the proxy, used by Prometheus to scrape the metrics
   - kind: Service
     apiVersion: v1
@@ -271,3 +270,8 @@ parameters:
     value: quay.io/openshiftio/codeready-toolchain/registration-service:latest
   - name: REPLICAS
     value: '3'
+  - name: REGISTRATION_SERVICE_COMMAND
+    description: >-
+      The command the registration service's container is going to be launch with. It must be specified as a
+      YAML array; for example: ["registration-service", "argument", "argument2", ..., "argumentN"].
+    value: '["registration-service"]'

make/go.mk

@@ -20,6 +20,19 @@ $(OUT_DIR)/operator:
 		-o $(OUT_DIR)/bin/host-operator \
 		./cmd/main.go
 
+.PHONY: build-debug
+## Build the operator without the optimizations and the inlining, to enable
+## remote debugging via Delve.
+build-debug: generate
+	@echo "building host-operator in ${GO_PACKAGE_PATH}"
+	$(Q)go version
+	$(Q)CGO_ENABLED=0 GOARCH=${goarch} GOOS=linux \
+		go build ${V_FLAG} \
+		-gcflags "all=-N -l" \
+		-ldflags "-X ${GO_PACKAGE_PATH}/version.Commit=${GIT_COMMIT_ID} -X ${GO_PACKAGE_PATH}/version.BuildTime=${BUILD_TIME}" \
+		-o $(OUT_DIR)/bin/host-operator \
+		./cmd/main.go
+
 .PHONY: vendor
 vendor:
 	$(Q)go mod vendor

make/podman.mk

@@ -4,17 +4,29 @@ IMAGE_TAG ?= ${GIT_COMMIT_ID_SHORT}
 IMAGE ?= ${TARGET_REGISTRY}/${QUAY_NAMESPACE}/${GO_PACKAGE_REPO_NAME}:${IMAGE_TAG}
 QUAY_USERNAME ?= ${QUAY_NAMESPACE}
 IMAGE_PLATFORM ?= linux/amd64
+TARGET_ARCH ?= $(subst /,-,${IMAGE_PLATFORM})
 
 .PHONY: podman-image
 ## Build the binary image
 podman-image: build
 	$(Q)podman build --platform ${IMAGE_PLATFORM} -f build/Dockerfile -t ${IMAGE} .
 
+.PHONY: podman-image-debug
+## Build the operator's image with Delve on it so that it is ready to attach a
+## debugger to it.
+podman-image-debug: build-debug
+	$(Q) podman build --platform "${IMAGE_PLATFORM}" --build-arg BUILD_TYPE='debug' --build-arg GOLANG_VERSION="$$(go version | awk '{print $$3}')" --build-arg TARGET_ARCH="${TARGET_ARCH}" --file build/Dockerfile --tag "${IMAGE}" .
+
 .PHONY: podman-push
 ## Push the binary image to quay.io registry
 podman-push: check-namespace podman-image
 	$(Q)podman push ${IMAGE}
 
+.PHONY: podman-push-debug
+## Push the image with the debugger in it to the repository.
+podman-push-debug: check-namespace podman-image-debug
+	$(Q)podman push ${IMAGE}
+
 .PHONY: check-namespace
 check-namespace:
 ifeq ($(QUAY_NAMESPACE),${GO_PACKAGE_ORG_NAME})