[Go] SBE implementation in Go using flyweights real-logic#765

To generate flyweights instead of structs, set the following flag:

```
sbe.go.generate.generate.flyweights=true
```

.gitignore

@@ -62,31 +62,56 @@ cppbuild/Win32
 
 # golang
 gocode/pkg
-gocode/src/baseline/*.go
-!gocode/src/baseline/*_test.go
-gocode/src/baseline-bigendian/*.go
-!gocode/src/baseline-bigendian/*_test.go
-gocode/src/composite/*.go
-!gocode/src/composite/*_test.go
-gocode/src/composite_elements/*.go
-!gocode/src/composite_elements/*_test.go
-gocode/src/since-deprecated/*.go
-!gocode/src/since-deprecated/*_test.go
-gocode/src/group_with_data*/*.go
-!gocode/src/group_with_data*/*_test.go
-gocode/src/mktdata/*.go
-!gocode/src/mktdata/*_test.go
-gocode/src/simple/*.go
-!gocode/src/simple/*_test.go
-gocode/src/issue*/*.go
-!gocode/src/issue*/*_test.go
-gocode/src/*/*/*.go
-!gocode/src/*/*/*_test.go
-gocode/src/example-schema/example-schema*
-gocode/src/example-schema/cpu.out
-gocode/src/example-socket-clientserver/example-socket-clientserver
-gocode/src/extension
-gocode/src/extension2
+gocode/src/struct/baseline/*.go
+!gocode/src/struct/baseline/*_test.go
+gocode/src/struct/baseline-bigendian/*.go
+!gocode/src/struct/baseline-bigendian/*_test.go
+gocode/src/struct/composite/*.go
+!gocode/src/struct/composite/*_test.go
+gocode/src/struct/composite_elements/*.go
+!gocode/src/struct/composite_elements/*_test.go
+gocode/src/struct/since-deprecated/*.go
+!gocode/src/struct/since-deprecated/*_test.go
+gocode/src/struct/group_with_data*/*.go
+!gocode/src/struct/group_with_data*/*_test.go
+gocode/src/struct/mktdata/*.go
+!gocode/src/struct/mktdata/*_test.go
+gocode/src/struct/simple/*.go
+!gocode/src/struct/simple/*_test.go
+gocode/src/struct/issue*/*.go
+!gocode/src/struct/issue*/*_test.go
+gocode/src/struct/*/*/*.go
+!gocode/src/struct/*/*/*_test.go
+gocode/src/struct/example-schema/example-schema*
+gocode/src/struct/example-schema/cpu.out
+gocode/src/struct/example-socket-clientserver/example-socket-clientserver
+gocode/src/struct/extension
+gocode/src/struct/extension2
+gocode/src/flyweight/baseline/*.go
+!gocode/src/flyweight/baseline/*_test.go
+gocode/src/flyweight/baseline-bigendian/*.go
+!gocode/src/flyweight/baseline-bigendian/*_test.go
+gocode/src/flyweight/composite/*.go
+!gocode/src/flyweight/composite/*_test.go
+gocode/src/flyweight/composite_elements/*.go
+!gocode/src/flyweight/composite_elements/*_test.go
+gocode/src/flyweight/since-deprecated/*.go
+!gocode/src/flyweight/since-deprecated/*_test.go
+gocode/src/flyweight/group_with_data*/*.go
+!gocode/src/flyweight/group_with_data*/*_test.go
+gocode/src/flyweight/mktdata/*.go
+!gocode/src/flyweight/mktdata/*_test.go
+gocode/src/flyweight/simple/*.go
+!gocode/src/flyweight/simple/*_test.go
+gocode/src/flyweight/issue*/*.go
+!gocode/src/flyweight/issue*/*_test.go
+gocode/src/flyweight/*/*/*.go
+!gocode/src/flyweight/*/*/*_test.go
+gocode/src/flyweight/example-schema/example-schema*
+gocode/src/flyweight/example-schema/cpu.out
+gocode/src/flyweight/example-socket-clientserver/example-socket-clientserver
+gocode/src/flyweight/extension
+gocode/src/flyweight/extension2
 
 # csharp
 csharp/*/bin

README.md

@@ -97,6 +97,8 @@ For convenience on Linux, a gnu Makefile is provided that runs some tests and co
     $ cd gocode
     # make # test, examples, bench
 
+Go supports both generating Go structs with encode / decode methods, and flyweights like the other languages. Structs are generated by default for compatibility. Set `sbe.go.generate.generate.flyweights=true` to generate flyweights.
+
 Users of golang generated code should see the [user
 documentation](https://github.com/real-logic/simple-binary-encoding/wiki/Golang-User-Guide).
 

build.gradle

@@ -627,7 +627,7 @@ tasks.register('generateGolangCodecTestComposite', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src',
+            'sbe.output.dir': 'gocode/src/struct',
             'sbe.target.language': 'golang')
     args = ['sbe-tool/src/test/resources/composite-elements-schema-rc4.xml']
 }
@@ -636,7 +636,7 @@ tasks.register('generateGolangCodecTestBasic', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src/basic',
+            'sbe.output.dir': 'gocode/src/struct/basic',
             'sbe.target.language': 'golang')
     args = ['sbe-tool/src/test/resources/basic-types-schema.xml']
 }
@@ -645,7 +645,7 @@ tasks.register('generateGolangCodecTestGroup', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src/group',
+            'sbe.output.dir': 'gocode/src/struct/group',
             'sbe.target.language': 'golang')
     args = ['sbe-tool/src/test/resources/basic-group-schema.xml']
 }
@@ -654,7 +654,7 @@ tasks.register('generateGolangCodecTestVarData', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src/vardata',
+            'sbe.output.dir': 'gocode/src/struct/vardata',
             'sbe.target.language': 'golang')
     args = ['sbe-tool/src/test/resources/basic-variable-length-schema.xml']
 }
@@ -663,7 +663,7 @@ tasks.register('generateGolangCodecsWithXIncludes', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src',
+            'sbe.output.dir': 'gocode/src/struct',
             'sbe.target.language': 'golang',
             'sbe.xinclude.aware': 'true',
             'sbe.validation.xsd': validationXsdPath)
@@ -675,7 +675,87 @@ tasks.register('generateGolangCodecsWithXSD', JavaExec) {
     mainClass.set('uk.co.real_logic.sbe.SbeTool')
     classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
     systemProperties(
-            'sbe.output.dir': 'gocode/src',
+            'sbe.output.dir': 'gocode/src/struct',
+            'sbe.target.language': 'golang',
+            'sbe.xinclude.aware': 'true',
+            'sbe.validation.xsd': validationXsdPath)
+    args = ['sbe-tool/src/test/resources/group-with-data-schema.xml',
+            'sbe-tool/src/test/resources/FixBinary.xml',
+            'sbe-tool/src/test/resources/issue435.xml',
+            'sbe-tool/src/test/resources/issue472.xml',
+            'sbe-tool/src/test/resources/issue483.xml',
+            'sbe-tool/src/test/resources/issue488.xml',
+            'sbe-tool/src/test/resources/issue560.xml',
+            'sbe-tool/src/test/resources/issue661.xml',
+            'sbe-tool/src/test/resources/issue847.xml',
+            'sbe-tool/src/test/resources/issue848.xml',
+            'sbe-tool/src/test/resources/issue849.xml',
+            'sbe-tool/src/test/resources/since-deprecated-test-schema.xml',
+            'sbe-tool/src/test/resources/example-bigendian-test-schema.xml',
+            'gocode/resources/example-composite.xml',
+            'gocode/resources/group-with-data-extension-schema.xml',
+            'gocode/resources/simple.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecTestComposite', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight',
+            'sbe.go.generate.generate.flyweights': 'true',
+            'sbe.target.language': 'golang')
+    args = ['sbe-tool/src/test/resources/composite-elements-schema-rc4.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecTestBasic', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight/basic',
+            'sbe.go.generate.generate.flyweights': 'true',
+            'sbe.target.language': 'golang')
+    args = ['sbe-tool/src/test/resources/basic-types-schema.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecTestGroup', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight/group',
+            'sbe.go.generate.generate.flyweights': 'true',
+            'sbe.target.language': 'golang')
+    args = ['sbe-tool/src/test/resources/basic-group-schema.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecTestVarData', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight/vardata',
+            'sbe.go.generate.generate.flyweights': 'true',
+            'sbe.target.language': 'golang')
+    args = ['sbe-tool/src/test/resources/basic-variable-length-schema.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecsWithXIncludes', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight',
+            'sbe.go.generate.generate.flyweights': 'true',
+            'sbe.target.language': 'golang',
+            'sbe.xinclude.aware': 'true',
+            'sbe.validation.xsd': validationXsdPath)
+    args = ['sbe-samples/src/main/resources/example-schema.xml',
+            'sbe-samples/src/main/resources/example-extension-schema.xml']
+}
+
+tasks.register('generateGolangFlyweightCodecsWithXSD', JavaExec) {
+    mainClass.set('uk.co.real_logic.sbe.SbeTool')
+    classpath = project(':sbe-tool').sourceSets.main.runtimeClasspath
+    systemProperties(
+            'sbe.output.dir': 'gocode/src/flyweight',
+            'sbe.go.generate.generate.flyweights': 'true',
             'sbe.target.language': 'golang',
             'sbe.xinclude.aware': 'true',
             'sbe.validation.xsd': validationXsdPath)
@@ -704,7 +784,13 @@ tasks.register('generateGolangCodecs') {
             'generateGolangCodecTestBasic',
             'generateGolangCodecTestComposite',
             'generateGolangCodecsWithXIncludes',
-            'generateGolangCodecsWithXSD'
+            'generateGolangCodecsWithXSD',
+            'generateGolangFlyweightCodecTestVarData',
+            'generateGolangFlyweightCodecTestGroup',
+            'generateGolangFlyweightCodecTestBasic',
+            'generateGolangFlyweightCodecTestComposite',
+            'generateGolangFlyweightCodecsWithXIncludes',
+            'generateGolangFlyweightCodecsWithXSD'
 }
 
 /*

gocode/Makefile

@@ -19,68 +19,91 @@ all: example test # bench
 # This target is used to build golang files using parent gradle
 # script's invocation of sbe-tool in case it needs to be run again. We
 # use this one output file to check that dependency as it's simple
-DEP=src/simple/SbeMarshalling.go
+DEP=src/struct/simple/SbeMarshalling.go
 $(DEP): $(SBE_JAR)
 	(cd ..; ./gradlew generateGolangCodecs)
 	(export GOPATH=$(GOPATH) && \
-	cd src/simple && \
+	cd src/struct/simple && \
 	go build && \
 	$(SAVE_FORMAT) \
 	go fmt && \
 	go test)
 
 # Will regenerate codecs by removing dependencies
 clean:
-	rm -f src/*/SbeMarshalling.go src/*/*/SbeMarshalling.go
+	rm -f src/struct/*/SbeMarshalling.go src/struct/*/*/SbeMarshalling.go
 
 # Example code and benchmarking 
-example: src/example-schema/example-schema
-src/example-schema/example-schema: $(DEP)
+example: src/struct/example-schema/example-schema
+src/struct/example-schema/example-schema: $(DEP)
 	(export GOPATH=$(GOPATH) && \
-	cd src/example-schema && \
+	cd src/struct/example-schema && \
 	go build && \
 	go fmt && \
 	./example-schema)
 
 bench: $(DEP)
 	(export GOPATH=$(GOPATH) && \
-        cd src/example-schema && \
+        cd src/struct/example-schema && \
 	go test --bench . -cpuprofile=cpu.out && \
 	go tool pprof -text example-schema.test cpu.out)
 
-src/baseline/SbeMarshalling.go: $(DEP)
+src/struct/baseline/SbeMarshalling.go: $(DEP)
 	$(GOPATH)/sbe-tool -d src -s $(EXAMPLES_SCHEMA)
 	(export GOPATH=$(GOPATH) && \
-        cd src/baseline && \
+        cd src/struct/baseline && \
 	go build && \
 	go fmt && \
 	go test && \
 	go install)
 
 # The first set does a make install as there is a test that uses
 # multiple packages and needs them in GOPATH The second set work in
-# src/foo, and the third need a GOPATH addition as for Java and C++
+# src/struct/foo, and the third need a GOPATH addition as for Java and C++
 # they generate into the same directory but golang doesn't allow that
 test: $(DEP)
 	(export GOPATH=$(GOPATH) && \
 		(for t in baseline extension; do \
 		export GOPATH=$(GOPATH) && \
-	        cd $(GOPATH)/src/$$t && \
+	        cd $(GOPATH)/src/struct/$$t && \
 		go build && \
 		go fmt && \
 		go test && \
 		go install \
 		;done))
 	(export GOPATH=$(GOPATH) && \
 		(for t in baseline-bigendian mktdata group_with_data group_with_data_extension composite_elements composite since-deprecated simple issue435 issue472 issue483 issue488 issue560 issue847 issue848 issue849; do \
-		cd $(GOPATH)/src/$$t && \
+		cd $(GOPATH)/src/struct/$$t && \
 		go build && \
 		go fmt && \
 		go test \
 		;done))
 	(for t in vardata group basic; do \
 		export GOPATH=$(GOPATH)/$$t && \
-		cd $(GOPATH)/src/$$t/'SBE tests' && \
+		cd $(GOPATH)/src/struct/$$t/'SBE tests' && \
+		go build && \
+		go fmt && \
+		go test \
+		;done)
+	(export GOPATH=$(GOPATH) && \
+		(for t in baseline extension; do \
+		export GOPATH=$(GOPATH) && \
+	        cd $(GOPATH)/src/flyweight/$$t && \
+		go build && \
+		go fmt && \
+		go test && \
+		go install \
+		;done))
+	(export GOPATH=$(GOPATH) && \
+		(for t in baseline-bigendian mktdata group_with_data group_with_data_extension composite_elements composite since-deprecated simple issue435 issue472 issue483 issue488 issue560 issue847 issue848 issue849; do \
+		cd $(GOPATH)/src/flyweight/$$t && \
+		go build && \
+		go fmt && \
+		go test \
+		;done))
+	(for t in vardata group basic; do \
+		export GOPATH=$(GOPATH)/$$t && \
+		cd $(GOPATH)/src/flyweight/$$t/'SBE tests' && \
 		go build && \
 		go fmt && \
 		go test \

gocode/README.md

@@ -5,10 +5,13 @@ There is now a
 [user guide](https://github.com/real-logic/simple-binary-encoding/wiki/Golang-User-Guide)
 and this document is for development of the SBE golang generator.
 
+Go supports both generating Go structs with encode / decode methods, and flyweights like the other languages.
+Structs are generated by default for compatibility. Set `sbe.go.generate.generate.flyweights=true` to generate flyweights.
+
 Code Layout
 -----------
 The Java code that performs the generation of golang code is
-[here](https://github.com/real-logic/simple-binary-encoding/tree/master/sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/golang).
+[here](https://github.com/real-logic/simple-binary-encoding/tree/master/sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/golang). There is both a struct and a flyweight generator.
 
 Golang code used for testing resides in the top-level
 [gocode directory](https://github.com/real-logic/simple-binary-encoding/tree/master/gocode).
@@ -24,11 +27,12 @@ the build environment, example and test code are structured into a top
 level gocode directory hierarchy.
 
 Code is generated into this structure with pre-existing test code in place.
+There are tests for both the struct and flyweight styles of generated code.
 
 For the example, the code is generated into a library and the matching
 example code lives in it's own directory at the same level. For
 example, the example-schema generates the baseline library code into
-`gocode/src/baseline` and example code lives in `gocode/src/example-schema`.
+`gocode/src/struct/baseline` and example code lives in `gocode/src/example-schema`.
 
 To use this layout you should `set GOPATH=/path/to/gocode` or use the
 supplied Makefile which does this for you. For the tests you will need
@@ -60,5 +64,3 @@ generator processes.
 Roadmap
 =======
  * Windows developer support (currently tested on Linux/MacOS)
- * Further Unicode support
- * Testing/Bug fixes

gocode/go.mod

@@ -0,0 +1,7 @@
+module github.com/real-logic/simple-binary-encoding
+
+go 1.12
+
+require (
+	github.com/stretchr/testify v1.7.0
+)

gocode/go.sum

@@ -0,0 +1,7 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=