Adding a hack/debug script

That's basically just a light wrapper around delve, to make it nicer to use
(stops it after the session is done, and doesn't ignore interrupts like
the vanilla version does).

Also amending the containerized Makefile to add the right run options
when using delve. That's controlled by the `DOCKER_SWARMKIT_USE_DELVE`
env variable; it's also possible to override the port delve uses
via the `DOCKER_SWARMKIT_DELVE_PORT` env variable.

Signed-off-by: Jean Rouge <jer329@cornell.edu>
(cherry picked from commit 0a88f50)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Makefile

@@ -1,29 +1,8 @@
 # Root directory of the project (absolute path).
 ROOTDIR=$(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 
-# Base path used to install.
-DESTDIR=/usr/local
-
-# Used to populate version variable in main package.
-VERSION=$(shell git describe --match 'v[0-9]*' --dirty='.m' --always)
-
 PROJECT_ROOT=github.com/docker/swarmkit
 
-# Race detector is only supported on amd64.
-RACE := $(shell test $$(go env GOARCH) != "amd64" || (echo "-race"))
-
-# Project packages.
-PACKAGES=$(shell go list ./... | grep -v /vendor/)
-INTEGRATION_PACKAGE=${PROJECT_ROOT}/integration
-
-# Project binaries.
-COMMANDS=swarmd swarmctl swarm-bench swarm-rafttool protoc-gen-gogoswarm
-BINARIES=$(addprefix bin/,$(COMMANDS))
-
-VNDR=$(shell which vndr || echo '')
-
-GO_LDFLAGS=-ldflags "-X `go list ./version`.Version=$(VERSION)"
-
 SHELL := /bin/bash
 
 # stop here. do we want to run everything inside of a container, or do we want

containerized.mk

@@ -2,6 +2,8 @@ IMAGE_NAME=docker/swarmkit
 GOPATH=/go
 DOCKER_IMAGE_DIR=${GOPATH}/src/${PROJECT_ROOT}
 
+DOCKER_SWARMKIT_DELVE_PORT ?= 2345
+
 # don't bother writing every single make target. just pass the call through to
 # docker and make
 # we prefer `%:` to `.DEFAULT` as the latter doesn't run phony deps
@@ -40,10 +42,16 @@ run: ensure_image_exists
 	@ [ "$$DOCKER_SWARMKIT_DOCKER_RUN_CMD" ] || exit 1
 	@ DOCKER_RUN_COMMAND="docker run -t -v swarmkit-cache:${GOPATH}" \
 		&& if [ "$$DOCKER_SWARMKIT_USE_DOCKER_SYNC" ]; then \
-			$(MAKE) ensure_sync_started && DOCKER_RUN_COMMAND="$$DOCKER_RUN_COMMAND -v swarmkit-sync:${DOCKER_IMAGE_DIR}"; \
+			$(MAKE) ensure_sync_started && DOCKER_RUN_COMMAND+=" -v swarmkit-sync:${DOCKER_IMAGE_DIR}"; \
 		else \
-			DOCKER_RUN_COMMAND="$$DOCKER_RUN_COMMAND -v ${ROOTDIR}:${DOCKER_IMAGE_DIR}"; \
+			DOCKER_RUN_COMMAND+=" -v ${ROOTDIR}:${DOCKER_IMAGE_DIR}"; \
+		fi \
+		&& if [ "$$DOCKER_SWARMKIT_USE_DELVE" ]; then \
+			DOCKER_RUN_COMMAND="DOCKER_SWARMKIT_DELVE_PORT=${DOCKER_SWARMKIT_DELVE_PORT} $$DOCKER_RUN_COMMAND" ; \
+			DOCKER_RUN_COMMAND+=" -p ${DOCKER_SWARMKIT_DELVE_PORT}:${DOCKER_SWARMKIT_DELVE_PORT} -e DOCKER_SWARMKIT_DELVE_PORT"; \
+			`# see https://github.com/derekparker/delve/issues/515#issuecomment-214911481'` ; \
+			DOCKER_RUN_COMMAND+=" --security-opt=seccomp:unconfined"; \
 		fi \
-		&& DOCKER_RUN_COMMAND="$$DOCKER_RUN_COMMAND $$DOCKER_SWARMKIT_DOCKER_RUN_FLAGS ${IMAGE_NAME} $$DOCKER_SWARMKIT_DOCKER_RUN_CMD" \
+		&& DOCKER_RUN_COMMAND+=" $$DOCKER_SWARMKIT_DOCKER_RUN_FLAGS ${IMAGE_NAME} $$DOCKER_SWARMKIT_DOCKER_RUN_CMD" \
 		&& echo $$DOCKER_RUN_COMMAND \
-		&& $$DOCKER_RUN_COMMAND
+		&& eval $$DOCKER_RUN_COMMAND

direct.mk

@@ -1,3 +1,25 @@
+# Base path used to install.
+DESTDIR=/usr/local
+
+# Used to populate version variable in main package.
+VERSION=$(shell git describe --match 'v[0-9]*' --dirty='.m' --always)
+
+# Race detector is only supported on amd64.
+RACE := $(shell test $$(go env GOARCH) != "amd64" || (echo "-race"))
+
+# Project packages.
+PACKAGES=$(shell go list ./... | grep -v /vendor/)
+INTEGRATION_PACKAGE=${PROJECT_ROOT}/integration
+
+# Project binaries.
+COMMANDS=swarmd swarmctl swarm-bench swarm-rafttool protoc-gen-gogoswarm
+BINARIES=$(addprefix bin/,$(COMMANDS))
+
+VNDR=$(shell which vndr || echo '')
+
+GO_LDFLAGS=-ldflags "-X `go list ./version`.Version=$(VERSION)"
+
+
 .DEFAULT_GOAL = all
 .PHONY: all
 all: check binaries test integration-tests ## run check, build the binaries and run the tests

hack/debug

@@ -0,0 +1,71 @@
+#!/bin/bash
+
+## Installs delve, then runs it as a headless server
+## Keeps running until killed
+## Also adds some goodies: delve servers ignore interrupts, which is annoying...
+## and also once a debugging session is done, the server just hangs there, which
+## is equally annoying.
+## This script takes care of both these things
+
+SUBSHELL_PID=
+DLV_PID_FILE=
+RUNNING=true
+
+main() {
+  [ "$1" ] || usage
+
+  ensure_delve_installed || exit $?
+
+  local PORT="$DOCKER_SWARMKIT_DELVE_PORT"
+  [ "$PORT" ] || PORT=2345
+
+  local DLV_CMD="dlv test --accept-multiclient --headless --listen=:$PORT --api-version=2 --log $@"
+  echo $DLV_CMD
+
+  trap handle_interrupt INT
+
+  DLV_PID_FILE=$(mktemp /tmp/dlv.XXXXXX.pid)
+  local DLV_OUTPUT_FILE=$(mktemp /tmp/dlv.XXXXXX.out)
+
+  # the weird regex is because we keep the output colored
+  local HALTING_REGEX='^\e\[37mDEBU\e\[0m\[[0-9]+\] halting\s+\e\[37mlayer\e\[0m=debugger'
+  while $RUNNING; do
+    # using `script` to keep colored output, and `exec` to get the PID from the
+    # subshell
+    script --flush --quiet "$DLV_OUTPUT_FILE" --command 'printf $$ > '"$DLV_PID_FILE && exec $DLV_CMD" &
+    SUBSHELL_PID=$!
+
+    # wait for either the subshell to die, or for the "halting" line to appear
+    # in the output
+    tail --follow --pid="$SUBSHELL_PID" --sleep-interval=0.1 "$DLV_OUTPUT_FILE" 2> /dev/null | grep --perl-regex --line-buffered "$HALTING_REGEX" | ( read && kill_delve )
+
+    wait "$SUBSHELL_PID"
+  done
+
+  rm -f "$DLV_PID_FILE" "$DLV_OUTPUT_FILE"
+}
+
+handle_interrupt() {
+  RUNNING=false
+  kill_delve
+}
+
+kill_delve() {
+  if [ -r "$DLV_PID_FILE" ]; then
+    local DLV_PID=$(cat "$DLV_PID_FILE")
+    [ "$DLV_PID" ] && kill "$DLV_PID" &> /dev/null
+  fi
+
+  [ "$SUBSHELL_PID" ] && kill $SUBSHELL_PID &> /dev/null
+}
+
+ensure_delve_installed() {
+  which dlv &> /dev/null || go get -u github.com/derekparker/delve/cmd/dlv
+}
+
+usage() {
+  echo "Usage: $0 name/of/go/package [additional dlv test options]"
+  exit 1
+}
+
+main "$@"