Debug mode for DLV debugger (#869)

* Debug mode for DLV debugger

* Changelog update

Author: jwierzbo

CHANGELOG.md

@@ -6,6 +6,7 @@
 - Remove unused `status.members.<group>.sidecars-specs` variable
 - Keep only recent terminations
 - Add endpoint into member status
+- Add debug mode (Golang DLV)
 
 ## [1.2.6](https://github.com/arangodb/kube-arangodb/tree/1.2.6) (2021-12-15)
 - Add ArangoBackup backoff functionality

Dockerfile

@@ -16,4 +16,4 @@ ARG RELEASE_MODE=community
 ARG TARGETARCH=amd64
 ADD bin/${RELEASE_MODE}/linux/${TARGETARCH}/arangodb_operator /usr/bin/arangodb_operator
 
-ENTRYPOINT [ "/usr/bin/arangodb_operator" ]
+ENTRYPOINT [ "/usr/bin/arangodb_operator" ]

Dockerfile.debug

@@ -0,0 +1,30 @@
+FROM golang:1.16 as builder
+
+ARG TARGETARCH
+
+RUN apt-get update && apt-get install -y build-essential
+RUN go install github.com/go-delve/delve/cmd/dlv@latest
+
+FROM alpine:3.14 as artifact
+
+ARG RELEASE_MODE
+ARG TARGETARCH
+ARG VERSION
+
+LABEL name="kube-arangodb" \
+      vendor="ArangoDB" \
+      version="${VERSION}" \
+      release="${VERSION}" \
+      summary="ArangoDB Kubernetes Oparator" \
+      description="ArangoDB Kubernetes Operator" \
+      maintainer="redhat@arangodb.com"
+
+RUN apk add --no-cache libc6-compat
+
+ADD ./LICENSE /licenses/LICENSE
+ADD bin/${RELEASE_MODE}/linux/${TARGETARCH}/arangodb_operator /usr/bin/arangodb_operator
+
+COPY --from=builder /go/bin/dlv /usr/bin/dlv
+
+ENTRYPOINT ["/usr/bin/dlv", "--listen=:2345", "--headless=true", "--continue", "--accept-multiclient", "--api-version=2", "exec", "/usr/bin/arangodb_operator", "--" ]
+

MAINTAINERS.md

@@ -33,6 +33,18 @@ To run only a single test, set `TESTOPTIONS` to something like
 `-test.run=TestRocksDBEncryptionSingle` where
 `TestRocksDBEncryptionSingle` is the name of the test.
 
+## Debugging with DLV
+
+To attach DLV debugger, first prepare operator image with DLV server included:
+```shell
+IMAGETAG=1.2.4dlv DEBUG=true make docker
+```
+
+Then deploy it on your k8s and use following command to access DLV server on `localhost:2345` from your local machine:
+```shell
+kubectl port-forward deployment/arango-arango-deployment-operator 2345
+```
+
 ## Preparing a release
 
 To prepare for a release, do the following:
@@ -76,3 +88,17 @@ If the release process fails, it may leave:
   To resolve remove it using `git tag -d ...`.
 - A git tag named `<major>.<minor>.<patch>` in this repository in github.
   To resolve remove it manually.
+
+## Development on MacOS
+
+This repo requires GNU command line tools instead BSD one (which are by default available on Mac).
+```shell
+brew install coreutils ed findutils gawk gnu-sed gnu-tar grep make
+```
+
+Please add following to your `~/bashrc` or `~/.zshrc` file (it requires Homebrew to be installed):
+
+```shell
+HOMEBREW_PREFIX=$(brew --prefix)
+for d in ${HOMEBREW_PREFIX}/opt/*/libexec/gnubin; do export PATH=$d:$PATH; done
+```

Makefile

@@ -39,8 +39,6 @@ GOASSETSBUILDER := $(GOBUILDDIR)/bin/go-assets-builder$(shell go env GOEXE)
 
 BUILDTIME = $(shell go run "$(ROOT)/tools/dategen/")
 
-DOCKERFILE := Dockerfile
-
 HELM ?= $(shell which helm)
 
 UPPER = $(shell echo '$1' | tr '[:lower:]' '[:upper:]')
@@ -62,6 +60,7 @@ HELM_CMD = $(HELM) template "$(ROOTDIR)/chart/$(CHART_NAME)" \
          	       --set "operator.image=$(OPERATORIMAGE)" \
          	       --set "operator.imagePullPolicy=Always" \
          	       --set "operator.resources=null" \
+         	       --set "operator.debug=$(DEBUG)" \
          	       --namespace "$(DEPLOYMENTNAMESPACE)"
 
 ifndef LOCALONLY
@@ -74,6 +73,17 @@ else
 	IMAGESUFFIX := :dev
 endif
 
+ifdef DEBUG
+	DEBUG := true
+	DOCKERFILE := Dockerfile.debug
+	# required by DLV https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_exec.md
+	COMPILE_DEBUG_FLAGS := -gcflags="all=-N -l"
+else
+	DEBUG := false
+	DOCKERFILE := Dockerfile
+	COMPILE_DEBUG_FLAGS :=
+endif
+
 ifeq ($(MANIFESTSUFFIX),-)
 	# Release setting
 	MANIFESTSUFFIX :=
@@ -257,11 +267,11 @@ bin-all: $(BIN) $(VBIN_LINUX_AMD64) $(VBIN_LINUX_ARM64)
 
 $(VBIN_LINUX_AMD64): $(SOURCES) dashboard/assets.go VERSION
 	@mkdir -p $(BINDIR)/$(RELEASE_MODE)/linux/amd64
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build --tags "$(RELEASE_MODE)" -installsuffix netgo -ldflags "-X $(REPOPATH)/pkg/version.version=$(VERSION) -X $(REPOPATH)/pkg/version.buildDate=$(BUILDTIME) -X $(REPOPATH)/pkg/version.build=$(COMMIT)" -o $(VBIN_LINUX_AMD64) ./
+	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build --tags "$(RELEASE_MODE)" $(COMPILE_DEBUG_FLAGS) -installsuffix netgo -ldflags "-X $(REPOPATH)/pkg/version.version=$(VERSION) -X $(REPOPATH)/pkg/version.buildDate=$(BUILDTIME) -X $(REPOPATH)/pkg/version.build=$(COMMIT)" -o $(VBIN_LINUX_AMD64) ./
 
 $(VBIN_LINUX_ARM64): $(SOURCES) dashboard/assets.go VERSION
 	@mkdir -p $(BINDIR)/$(RELEASE_MODE)/linux/arm64
-	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build --tags "$(RELEASE_MODE)" -installsuffix netgo -ldflags "-X $(REPOPATH)/pkg/version.version=$(VERSION) -X $(REPOPATH)/pkg/version.buildDate=$(BUILDTIME) -X $(REPOPATH)/pkg/version.build=$(COMMIT)" -o $(VBIN_LINUX_ARM64) ./
+	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build --tags "$(RELEASE_MODE)" $(COMPILE_DEBUG_FLAGS) -installsuffix netgo -ldflags "-X $(REPOPATH)/pkg/version.version=$(VERSION) -X $(REPOPATH)/pkg/version.buildDate=$(BUILDTIME) -X $(REPOPATH)/pkg/version.build=$(COMMIT)" -o $(VBIN_LINUX_ARM64) ./
 
 $(BIN): $(VBIN_LINUX_AMD64)
 	@cp "$(VBIN_LINUX_AMD64)" "$(BIN)"

chart/kube-arangodb/templates/deployment.yaml

@@ -24,7 +24,11 @@ metadata:
         app.kubernetes.io/instance: {{ .Release.Name }}
         release: {{ .Release.Name }}
 spec:
+{{- if .Values.operator.debug }}
+    replicas: 1
+{{- else }}
     replicas: {{ .Values.operator.replicaCount }}
+{{- end }}
     strategy:
 {{ toYaml .Values.operator.updateStrategy | indent 8 }}
     selector:
@@ -134,10 +138,15 @@ spec:
                       capabilities:
                           drop:
                               - 'ALL'
+{{- if .Values.operator.debug }}
+                          add:
+                            - 'SYS_PTRACE'
+{{- end }}
 {{- if .Values.operator.resources }}
                   resources:
 {{ toYaml .Values.operator.resources | indent 22 }}
 {{- end }}
+{{- if not .Values.operator.debug }}
                   livenessProbe:
                       httpGet:
                           path: /health
@@ -152,6 +161,7 @@ spec:
                           scheme: HTTPS
                       initialDelaySeconds: 5
                       periodSeconds: 10
+{{- end }}
             tolerations:
                 - key: "node.kubernetes.io/unreachable"
                   operator: "Exists"

chart/kube-arangodb/values.yaml

@@ -7,6 +7,8 @@ operator:
 
   scope: legacy
 
+  debug: false
+
   args: []
 
   service:

docs/design/maintenance.md

@@ -1,16 +1,5 @@
 # Maintenance
 
-## Development on MacOS
-
-This repo requires GNU command line tools instead BSD one (which are by default available on Mac).
-
-Please add following to your `~/bashrc` or `~/.zshrc` file (it requires Hombebrew to be installed):
-
-```shell
-HOMEBREW_PREFIX=$(brew --prefix)
-for d in ${HOMEBREW_PREFIX}/opt/*/libexec/gnubin; do export PATH=$d:$PATH; done
-```
-
 ## ArangoDeployment
 
 Maintenance on ArangoDeployment can be enabled using annotation.