adds source debug build options

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

Makefile

@@ -62,6 +62,10 @@ GOLDFLAGS ?=
 KUBE_GOLDFLAGS = $(GOLDFLAGS)
 export KUBE_GOLDFLAGS GOLDFLAGS
 
+GOGCFLAGS ?=
+KUBE_GOGCFLAGS = $(GOGCFLAGS)
+export KUBE_GOGCFLAGS GOGCFLAGS
+
 # Build code.
 #
 # Args:
@@ -69,12 +73,17 @@ export KUBE_GOLDFLAGS GOLDFLAGS
 #     package, the build will produce executable files under $(OUT_DIR)/go/bin.
 #     If not specified, "everything" will be built.
 #   GOFLAGS: Extra flags to pass to 'go' when building.
-#   GOLDFLAGS: Extra linking flags to pass to 'go' when building.
+#   GOLDFLAGS: Extra linking flags passed to 'go' when building.
+#   GOGCFLAGS: Additional go compile flags passed to 'go' when building.
 #
 # Example:
 #   make
 #   make all
 #   make all WHAT=cmd/kubelet GOFLAGS=-v
+#   make all GOGCFLAGS="-N -l"
+#     Note: Use the -N -l options to disable compiler optimizations an inlining.
+#           Using these build options allows you to subsequently use source
+#           debugging tools like delve.
 .PHONY: all
 all: generated_files
 	hack/make-rules/build.sh $(WHAT)
@@ -107,6 +116,7 @@ verify:
 #   TESTS: Same as WHAT.
 #   GOFLAGS: Extra flags to pass to 'go' when building.
 #   GOLDFLAGS: Extra linking flags to pass to 'go' when building.
+#   GOGCFLAGS: Additional go compile flags passed to 'go' when building.
 #
 # Example:
 #   make check

docs/devel/development.md

@@ -75,8 +75,14 @@ binaries):
         make
 ```
 
-You may pass build options and packages to the script as necessary. To build
+You may pass build options and packages to the script as necessary. For example,
-binaries for all platforms:
+to build with optimizations disabled for enabling use of source debug tools:
+
+```sh
+        make GOGCFLAGS="-N -l"
+```
+
+To build binaries for all platforms:
 
 ```sh
         make cross

hack/lib/golang.sh

@@ -426,6 +426,7 @@ kube::golang::build_kube_toolchain() {
 
   kube::log::status "Building the toolchain targets:" "${binaries[@]}"
   go install "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${binaries[@]:+${binaries[@]}}"
 }
@@ -482,6 +483,7 @@ kube::golang::build_binaries_for_platform() {
       local outfile=$(kube::golang::output_filename_for_binary "${binary}" "${platform}")
       CGO_ENABLED=0 go build -o "${outfile}" \
         "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${binary}"
       kube::log::progress "*"
@@ -490,6 +492,7 @@ kube::golang::build_binaries_for_platform() {
       local outfile=$(kube::golang::output_filename_for_binary "${binary}" "${platform}")
       go build -o "${outfile}" \
         "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${binary}"
       kube::log::progress "*"
@@ -499,11 +502,13 @@ kube::golang::build_binaries_for_platform() {
     # Use go install.
     if [[ "${#nonstatics[@]}" != 0 ]]; then
       go install "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${nonstatics[@]:+${nonstatics[@]}}"
     fi
     if [[ "${#statics[@]}" != 0 ]]; then
       CGO_ENABLED=0 go install -installsuffix cgo "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${statics[@]:+${statics[@]}}"
     fi
@@ -536,12 +541,14 @@ kube::golang::build_binaries_for_platform() {
     # returns true (always stale). And that's why we need to install the
     # test package.
     go install "${goflags[@]:+${goflags[@]}}" \
+        -gcflags "${gogcflags}" \
         -ldflags "${goldflags}" \
         "${testpkg}"
 
     mkdir -p "$(dirname ${outfile})"
     go test -c \
       "${goflags[@]:+${goflags[@]}}" \
+      -gcflags "${gogcflags}" \
       -ldflags "${goldflags}" \
       -o "${outfile}" \
       "${testpkg}"
@@ -595,9 +602,10 @@ kube::golang::build_binaries() {
     host_platform=$(kube::golang::host_platform)
 
     # Use eval to preserve embedded quoted strings.
-    local goflags goldflags
+    local goflags goldflags gogcflags
     eval "goflags=(${KUBE_GOFLAGS:-})"
     goldflags="${KUBE_GOLDFLAGS:-} $(kube::version::ldflags)"
+    gogcflags="${KUBE_GOGCFLAGS:-}"
 
     local use_go_build
     local -a targets=()