internal/keyvaluetags: Use build constraint with custom implementatio…

…n files, add gencheck Makefile target and add to CI (#11638)

* Move custom service-specific functions to own package.
This ensures that `make gen` succeeds.

* Add 'gen' to 'test' and 'testacc' targets.

* Revert "Add 'gen' to 'test' and 'testacc' targets."

This reverts commit 2e6008bbe4c1e33ad6ed4dc08019e207cd29939e.

* Revert "Move custom service-specific functions to own package."

This reverts commit 2d050db0cf29919336f9b1b1898856601763403b.

* Use build constraints to prevent 'go generate' errors with custom keyvaluetags implementations.

* Add 'gencheck' build target.

If there are differences we get an error like:

% make gencheck
==> Checking generated source code...
rm -f aws/internal/keyvaluetags/*_gen.go
go generate ./...
 GNUmakefile | 6 ++++++
 1 file changed, 6 insertions(+)

Unexpected difference in directories after code generation. Run 'make gen' command and commit.
make: *** [gencheck] Error 1

If there are no differences:

% make gencheck
==> Checking generated source code...
rm -f aws/internal/keyvaluetags/*_gen.go
go generate ./...

* Run 'make gencheck' during Travis Code UnitTest pass.

.travis.yml

@@ -17,7 +17,9 @@ matrix:
       script: make lint
     - go: "1.13.x"
       name: "Code UnitTest"
-      script: make test
+      script:
+        - make test
+        - make gencheck
     - go: "1.13.x"
       name: "Dependencies"
       script: make depscheck

GNUmakefile

@@ -31,6 +31,12 @@ fmt:
 fmtcheck:
 	@sh -c "'$(CURDIR)/scripts/gofmtcheck.sh'"
 
+gencheck:
+	@echo "==> Checking generated source code..."
+	@$(MAKE) gen
+	@git diff --compact-summary --exit-code || \
+		(echo; echo "Unexpected difference in directories after code generation. Run 'make gen' command and commit."; exit 1)
+
 websitefmtcheck:
 	@sh -c "'$(CURDIR)/scripts/websitefmtcheck.sh'"
 

aws/internal/keyvaluetags/iam_tags.go

@@ -1,3 +1,5 @@
+// +build !generate
+
 package keyvaluetags
 
 import (

aws/internal/keyvaluetags/key_value_tags.go

@@ -1,6 +1,6 @@
-//go:generate go run generators/servicetags/main.go
-//go:generate go run generators/listtags/main.go
-//go:generate go run generators/updatetags/main.go
+//go:generate go run -tags generate generators/servicetags/main.go
+//go:generate go run -tags generate generators/listtags/main.go
+//go:generate go run -tags generate generators/updatetags/main.go
 
 package keyvaluetags