Update makefile to generate defaulters

Makefile.generated_files

@@ -35,7 +35,7 @@ SHELL := /bin/bash
 # This rule collects all the generated file sets into a single rule.  Other
 # rules should depend on this to ensure generated files are rebuilt.
 .PHONY: generated_files
-generated_files: gen_deepcopy gen_conversion gen_openapi
+generated_files: gen_deepcopy gen_defaulter gen_conversion gen_openapi
 
 # Code-generation logic.
 #
@@ -286,6 +286,146 @@ $(DEEPCOPY_GEN):
 	hack/make-rules/build.sh cmd/libs/go2idl/deepcopy-gen
 	touch $@
 
+#
+# Defaulter generation
+#
+# Any package that wants defaulter functions generated must include a
+# comment-tag in column 0 of one file of the form:
+#     // +k8s:defaulter-gen=<VALUE>
+#
+# The <VALUE> depends on context:
+#     on types:
+#       true:  always generate a defaulter for this type
+#       false: never generate a defaulter for this type
+#     on functions:
+#       covers: if the function name matches SetDefault_NAME, instructs
+#               the generator not to recurse
+#     on packages:
+#       FIELDNAME: any object with a field of this name is a candidate
+#                  for having a defaulter generated
+
+# The result file, in each pkg, of defaulter generation.
+DEFAULTER_BASENAME := $(GENERATED_FILE_PREFIX)defaults
+DEFAULTER_FILENAME := $(DEFAULTER_BASENAME).go
+
+# The tool used to generate defaulters.
+DEFAULTER_GEN := $(BIN_DIR)/defaulter-gen
+
+# All directories that request any form of defaulter generation.
+ifeq ($(DBG_MAKEFILE),1)
+    $(warning ***** finding all +k8s:defaulter-gen tags)
+endif
+DEFAULTER_DIRS := $(shell                                            \
+    grep --color=never -l '+k8s:defaulter-gen=' $(ALL_K8S_TAG_FILES) \
+        | xargs -n1 dirname                                          \
+        | sort -u                                                    \
+)
+
+DEFAULTER_FILES := $(addsuffix /$(DEFAULTER_FILENAME), $(DEFAULTER_DIRS))
+
+# This rule aggregates the set of files to generate and then generates them all
+# in a single run of the tool.
+.PHONY: gen_defaulter
+gen_defaulter: $(DEFAULTER_FILES)
+	if [[ -f $(META_DIR)/$(DEFAULTER_GEN).todo ]]; then                  \
+	    ./hack/run-in-gopath.sh $(DEFAULTER_GEN)                         \
+	        --v $(KUBE_VERBOSE)                                          \
+	        --logtostderr                                                \
+	        -i $$(cat $(META_DIR)/$(DEFAULTER_GEN).todo | paste -sd, -)  \
+	        --extra-peer-dirs $$(echo $(addprefix $(PRJ_SRC_PATH)/, $(DEFAULTER_DIRS)) | sed 's/ /,/g') \
+	        -O $(DEFAULTER_BASENAME);                                    \
+	fi
+
+# For each dir in DEFAULTER_DIRS, this establishes a dependency between the
+# output file and the input files that should trigger a rebuild.
+#
+# The variable value was set in $(GOFILES_META) and included as part of the
+# dependency management logic.
+#
+# Note that this is a deps-only statement, not a full rule (see below).  This
+# has to be done in a distinct step because wildcards don't work in static
+# pattern rules.
+#
+# The '$(eval)' is needed because this has a different RHS for each LHS, and
+# would otherwise produce results that make can't parse.
+#
+# We depend on the $(GOFILES_META).stamp to detect when the set of input files
+# has changed.  This allows us to detect deleted input files.
+$(foreach dir, $(DEFAULTER_DIRS), $(eval                                    \
+    $(dir)/$(DEFAULTER_FILENAME): $(META_DIR)/$(dir)/$(GOFILES_META).stamp  \
+                                   $(gofiles__$(dir))                       \
+))
+
+# For each dir in DEFAULTER_DIRS, for each target in $(defaulters__$(dir)),
+# this establishes a dependency between the output file and the input files
+# that should trigger a rebuild.
+#
+# The variable value was set in $(GOFILES_META) and included as part of the
+# dependency management logic.
+#
+# Note that this is a deps-only statement, not a full rule (see below).  This
+# has to be done in a distinct step because wildcards don't work in static
+# pattern rules.
+#
+# The '$(eval)' is needed because this has a different RHS for each LHS, and
+# would otherwise produce results that make can't parse.
+#
+# We depend on the $(GOFILES_META).stamp to detect when the set of input files
+# has changed.  This allows us to detect deleted input files.
+$(foreach dir, $(DEFAULTER_DIRS),                                               \
+    $(foreach tgt, $(defaulters__$(dir)), $(eval                                \
+        $(dir)/$(DEFAULTER_FILENAME): $(META_DIR)/$(tgt)/$(GOFILES_META).stamp  \
+                                       $(gofiles__$(tgt))                       \
+    ))                                                                          \
+)
+
+# Unilaterally remove any leftovers from previous runs.
+$(shell rm -f $(META_DIR)/$(DEFAULTER_GEN)*.todo)
+
+# How to regenerate defaulter code.  This is a little slow to run, so we batch
+# it up and trigger the batch from the 'generated_files' target.
+$(DEFAULTER_FILES): $(DEFAULTER_GEN)
+	mkdir -p $$(dirname $(META_DIR)/$(DEFAULTER_GEN))
+	echo $(PRJ_SRC_PATH)/$(@D) >> $(META_DIR)/$(DEFAULTER_GEN).todo
+
+# This calculates the dependencies for the generator tool, so we only rebuild
+# it when needed.  It is PHONY so that it always runs, but it only updates the
+# file if the contents have actually changed.  We 'sinclude' this later.
+.PHONY: $(META_DIR)/$(DEFAULTER_GEN).mk
+$(META_DIR)/$(DEFAULTER_GEN).mk:
+	mkdir -p $(@D);                                        \
+	(echo -n "$(DEFAULTER_GEN): ";                         \
+	 DIRECT=$$(go list -f '{{.Dir}} {{.Dir}}/*.go'         \
+	     ./cmd/libs/go2idl/defaulter-gen);                 \
+	 INDIRECT=$$(go list                                   \
+	     -f '{{range .Deps}}{{.}}{{"\n"}}{{end}}'          \
+	     ./cmd/libs/go2idl/defaulter-gen                   \
+	     | grep --color=never "^$(PRJ_SRC_PATH)"           \
+	     | sed 's|^$(PRJ_SRC_PATH)|./|'                    \
+	     | xargs go list -f '{{.Dir}} {{.Dir}}/*.go');     \
+	 echo $$DIRECT $$INDIRECT                              \
+	     | sed 's/ / \\=,/g'                               \
+	     | tr '=,' '\n\t';                                 \
+	) | sed "s|$$(pwd -P)/||" > $@.tmp;                    \
+	cmp -s $@.tmp $@ || cat $@.tmp > $@ && rm -f $@.tmp
+
+# Include dependency info for the generator tool.  This will cause the rule of
+# the same name to be considered and if it is updated, make will restart.
+sinclude $(META_DIR)/$(DEFAULTER_GEN).mk
+
+# How to build the generator tool.  The deps for this are defined in
+# the $(DEFAULTER_GEN).mk, above.
+#
+# A word on the need to touch: This rule might trigger if, for example, a
+# non-Go file was added or deleted from a directory on which this depends.
+# This target needs to be reconsidered, but Go realizes it doesn't actually
+# have to be rebuilt.  In that case, make will forever see the dependency as
+# newer than the binary, and try to rebuild it over and over.  So we touch it,
+# and make is happy.
+$(DEFAULTER_GEN):
+	hack/make-rules/build.sh cmd/libs/go2idl/defaulter-gen
+	touch $@
+
 #
 # Open-api generation
 #
@@ -427,7 +567,7 @@ gen_conversion: $(CONVERSION_FILES)
 	if [[ -f $(META_DIR)/$(CONVERSION_GEN).todo ]]; then                  \
 	    ./hack/run-in-gopath.sh $(CONVERSION_GEN)                         \
 	        --v $(KUBE_VERBOSE)                                           \
-	        --logtostderr                                               \
+	        --logtostderr                                                 \
 	        -i $$(cat $(META_DIR)/$(CONVERSION_GEN).todo | paste -sd, -)  \
 	        -O $(CONVERSION_BASENAME);                                    \
 	fi