Strip CLI and plugin binaries to reduce their size

Overall binary reduction achieved by this commit:
- 28% decrease for Darwin
- 36% decrease for Linux and Windows

This commit does two optimizations:

1. Remove symbol tables (reduce about 30% for Linux/Windows, 22% for Mac)
--
When compiling the CLI and plugins, this commit adds the "-s" and "-w"
flags.  The "-s" flag omits the symbol table and debug information
while "-w" omits the DWARF symbol table.  These symbol tables are used
by debuggers.  The impact in removing them will be that it will not be
possible to use a debugger on a production binary; this is acceptable
and it is actually a standard approach to ship production binaries
without debug symbols.  If a debugger needs to be used, a binary can
built with the symbol tables.

Note that the removal of debug symbols does not prevent proper traces
from being shown in a go "panic".

To build a CLI with debug symbols use TANZU_CLI_ENABLE_DEBUG=1
To build plugins with debug symbols use PLUGIN_ENABLE_DEBUG=1

2. Disable function inlining (reduce about 6% on every OS)
--
Adding the flag "-gcflags=all=-l" removes function inlining.  This
normally reduces performance a little but saves space.  Considering we
are dealing with a CLI tool which does not perform CPU intensive
operations, the slight possible performance degradation is not of
concern.

Signed-off-by: Marc Khouzam <[email protected]>

Makefile

@@ -65,6 +65,12 @@ LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-cli/pkg/buildinfo.Date=$(BUILD_DAT
 LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-cli/pkg/buildinfo.SHA=$(BUILD_SHA)'
 LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-cli/pkg/buildinfo.Version=$(BUILD_VERSION)'
 
+# Remove debug symbols to reduce binary size
+# To build with debug symbols: TANZU_CLI_ENABLE_DEBUG=1
+ifeq ($(strip $(TANZU_CLI_ENABLE_DEBUG)),)
+LD_FLAGS += -w -s
+endif
+
 APT_IMAGE=ubuntu
 ifdef APT_BUILDER_IMAGE
 APT_IMAGE=$(APT_BUILDER_IMAGE)
@@ -133,9 +139,9 @@ build-cli-%: ##Build the Tanzu Core CLI for a platform
 	fi
 
 	@if [ "$(OS)" = "windows" ]; then \
-		GOOS=$(OS) GOARCH=$(ARCH) $(GO) build --ldflags "$(LD_FLAGS)"  -o "$(ARTIFACTS_DIR)/$(OS)/$(ARCH)/cli/core/$(BUILD_VERSION)/tanzu-cli-$(OS)_$(ARCH).exe" ./cmd/tanzu/main.go;\
+		GOOS=$(OS) GOARCH=$(ARCH) $(GO) build -gcflags=all="-l" --ldflags "$(LD_FLAGS)" -o "$(ARTIFACTS_DIR)/$(OS)/$(ARCH)/cli/core/$(BUILD_VERSION)/tanzu-cli-$(OS)_$(ARCH).exe" ./cmd/tanzu/main.go;\
 	else \
-		GOOS=$(OS) GOARCH=$(ARCH) $(GO) build --ldflags "$(LD_FLAGS)"  -o "$(ARTIFACTS_DIR)/$(OS)/$(ARCH)/cli/core/$(BUILD_VERSION)/tanzu-cli-$(OS)_$(ARCH)" ./cmd/tanzu/main.go;\
+		GOOS=$(OS) GOARCH=$(ARCH) $(GO) build -gcflags=all="-l" --ldflags "$(LD_FLAGS)" -o "$(ARTIFACTS_DIR)/$(OS)/$(ARCH)/cli/core/$(BUILD_VERSION)/tanzu-cli-$(OS)_$(ARCH)" ./cmd/tanzu/main.go;\
 	fi
 
 ## --------------------------------------

cmd/plugin/builder/template/plugintemplates/plugin-tooling.mk.tmpl

@@ -20,7 +20,15 @@ endif
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Date=$(PLUGIN_BUILD_DATE)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.SHA=$(PLUGIN_BUILD_SHA)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Version=$(PLUGIN_BUILD_VERSION)'
-PLUGIN_GO_FLAGS ?=
+
+# Remove debug symbols to reduce binary size
+# To build with debug symbols: PLUGIN_ENABLE_DEBUG=1
+ifeq ($(strip $(PLUGIN_ENABLE_DEBUG)),)
+PLUGIN_LD_FLAGS += -w -s
+endif
+
+# The below disables function inlining to reduce binary size
+PLUGIN_GO_FLAGS += -gcflags=all=-l
 
 # Add supported OS-ARCHITECTURE combinations here
 PLUGIN_BUILD_OS_ARCH ?= linux-amd64 windows-amd64 darwin-amd64 darwin-arm64 linux-arm64

docs/dev/README.md

@@ -54,6 +54,17 @@ To run e2e tests for the repository:
 make e2e-cli-core
 ```
 
+### Debugging
+
+By default the CLI is built without debug symbols to reduce its binary size;
+this has the side-effect of preventing the use of a debugger towards the built
+binary.  However, when using an IDE, a different binary is used, one built by
+the IDE, and therefore the debugger can be used directly from the IDE.
+
+If you require using a debugger directly on a CLI binary, you have to build
+a binary that includes the debug symbols.  You can build such a binary by using
+`TANZU_CLI_ENABLE_DEBUG=1` along with your build command.
+
 ## Centralized Discovery of Plugins
 
 The Tanzu CLI uses a system of plugins to provide functionality to interact

docs/plugindev/README.md

@@ -231,6 +231,17 @@ well.
 
 Edit the file as appropriate.
 
+### Debugging
+
+By default a plugin is built without debug symbols to reduce its binary size;
+this has the side-effect of preventing the use of a debugger towards the built
+binary.  However, when using an IDE, a different binary is used, one built by
+the IDE, and therefore the debugger can be used directly from the IDE.
+
+If you require using a debugger directly on a plugin binary, you have to build
+a binary that includes the debug symbols.  You can build such a binary by using
+`PLUGIN_ENABLE_DEBUG=1` along with your build command.
+
 ### Publishing a plugin
 
 To publish one or more built plugins to a target repository, one would need to

plugin-tooling.mk

@@ -24,7 +24,15 @@ endif
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Date=$(PLUGIN_BUILD_DATE)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.SHA=$(PLUGIN_BUILD_SHA)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Version=$(PLUGIN_BUILD_VERSION)'
-PLUGIN_GO_FLAGS ?=
+
+# Remove debug symbols to reduce binary size
+# To build with debug symbols: PLUGIN_ENABLE_DEBUG=1
+ifeq ($(strip $(PLUGIN_ENABLE_DEBUG)),)
+PLUGIN_LD_FLAGS += -w -s
+endif
+
+# The below disables function inlining to reduce binary size
+PLUGIN_GO_FLAGS += -gcflags=all=-l
 
 # Add supported OS-ARCHITECTURE combinations here
 PLUGIN_BUILD_OS_ARCH ?= linux-amd64 windows-amd64 darwin-amd64 darwin-arm64 linux-arm64

test/sample-plugin/plugin-tooling.mk

@@ -20,7 +20,15 @@ endif
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Date=$(PLUGIN_BUILD_DATE)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.SHA=$(PLUGIN_BUILD_SHA)'
 PLUGIN_LD_FLAGS += -X 'github.com/vmware-tanzu/tanzu-plugin-runtime/plugin/buildinfo.Version=$(PLUGIN_BUILD_VERSION)'
-PLUGIN_GO_FLAGS ?=
+
+# Remove debug symbols to reduce binary size
+# To build with debug symbols: PLUGIN_ENABLE_DEBUG=1
+ifeq ($(strip $(PLUGIN_ENABLE_DEBUG)),)
+PLUGIN_LD_FLAGS += -w -s
+endif
+
+# The below disables function inlining to reduce binary size
+PLUGIN_GO_FLAGS += -gcflags=all=-l
 
 # Add supported OS-ARCHITECTURE combinations here
 PLUGIN_BUILD_OS_ARCH ?= linux-amd64 windows-amd64 darwin-amd64 darwin-arm64 linux-arm64
@@ -88,8 +96,9 @@ plugin-install-local:
 .PHONY: plugin-build
 plugin-build: $(PLUGIN_BUILD_TARGETS) generate-plugin-bundle ## Build all plugin binaries for all supported os-arch
 
+.PHONY: plugin-build-local
 plugin-build-local: plugin-build-$(GOHOSTOS)-$(GOHOSTARCH) ## Build all plugin binaries for local platform
-	
+
 plugin-build-%:
 	$(eval ARCH = $(word 2,$(subst -, ,$*)))
 	$(eval OS = $(word 1,$(subst -, ,$*)))