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merged 1 commit into from
Nov 8, 2025
Merged

feat: add support for custom compressors in gRPC server configuration #27

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28 changes: 28 additions & 0 deletions cmd/protoc-gen-elixir-grpc/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,33 @@ defmodule Greeter.Server do
end
```

#### Custom Compressors

Specify custom compressor modules for your gRPC server:

```yaml
version: v2
plugins:
- local: protoc-gen-elixir
out: lib
- local: protoc-gen-elixir-grpc
out: lib
opt:
- compressors=GRPC.Compressor.Gzip
```

This generates:

```elixir
defmodule Greeter.Server do
use GRPC.Server,
service: Greeter.Service,
compressors: [GRPC.Compressor.Gzip]

# ... method delegates
end
```

#### Combining Options

You can combine multiple options:
Expand All @@ -123,6 +150,7 @@ plugins:
- http_transcode=true
- handler_module_prefix=MyApp.Handlers
- codecs=GRPC.Codec.Proto,GRPC.Codec.WebText,GRPC.Codec.JSON
- compressors=GRPC.Compressor.Gzip
```

### Basic Service Implementation
Expand Down
27 changes: 22 additions & 5 deletions cmd/protoc-gen-elixir-grpc/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -55,8 +55,9 @@ const (
handlerModulePrefixFlag = "handler_module_prefix"
httpTranscodeFlag = "http_transcode"
codecsFlag = "codecs"
compressorsFlag = "compressors"

usage = "\n\nFlags:\n -h, --help\tPrint this help and exit.\n --version\tPrint the version and exit.\n --handler_module_prefix\tCustom Elixir module prefix for handler modules instead of protobuf package.\n --http_transcode\tEnable HTTP transcoding support (adds http_transcode: true to use GRPC.Server).\n --codecs\tComma-separated list of codec modules (e.g., 'GRPC.Codec.Proto,GRPC.Codec.WebText,GRPC.Codec.JSON')."
usage = "\n\nFlags:\n -h, --help\tPrint this help and exit.\n --version\tPrint the version and exit.\n --handler_module_prefix\tCustom Elixir module prefix for handler modules instead of protobuf package.\n --http_transcode\tEnable HTTP transcoding support (adds http_transcode: true to use GRPC.Server).\n --codecs\tComma-separated list of codec modules (e.g., 'GRPC.Codec.Proto,GRPC.Codec.WebText,GRPC.Codec.JSON').\n --compressors\tComma-separated list of compressor modules (e.g., 'GRPC.Compressor.Gzip')."
)

func parsePluginParameters(paramStr string, flagSet *flag.FlagSet) error {
Expand Down Expand Up @@ -178,6 +179,11 @@ func main() {
"",
"Comma-separated list of codec modules (e.g., 'GRPC.Codec.Proto,GRPC.Codec.WebText,GRPC.Codec.JSON').",
)
compressors := flagSet.String(
compressorsFlag,
"",
"Comma-separated list of compressor modules (e.g., 'GRPC.Compressor.Gzip').",
)

input, err := io.ReadAll(os.Stdin)
if err != nil {
Expand Down Expand Up @@ -214,6 +220,7 @@ func main() {
}

codecsList := parseCodecs(*codecs)
compressorsList := parseCodecs(*compressors)

for _, fileName := range req.FileToGenerate {
var protoFile *descriptorpb.FileDescriptorProto
Expand All @@ -231,7 +238,7 @@ func main() {
continue
}

generateElixirFile(resp, protoFile, *packagePrefix, *handlerModulePrefix, *httpTranscode, codecsList)
generateElixirFile(resp, protoFile, *packagePrefix, *handlerModulePrefix, *httpTranscode, codecsList, compressorsList)
}

output, err := proto.Marshal(resp)
Expand All @@ -246,7 +253,7 @@ func main() {
}
}

func generateElixirFile(resp *pluginpb.CodeGeneratorResponse, file *descriptorpb.FileDescriptorProto, packagePrefix, handlerModulePrefix string, httpTranscode bool, codecs []string) {
func generateElixirFile(resp *pluginpb.CodeGeneratorResponse, file *descriptorpb.FileDescriptorProto, packagePrefix, handlerModulePrefix string, httpTranscode bool, codecs []string, compressors []string) {
if len(file.Service) == 0 {
return
}
Expand All @@ -260,7 +267,7 @@ func generateElixirFile(resp *pluginpb.CodeGeneratorResponse, file *descriptorpb
content.WriteString("\n")

for _, service := range file.Service {
generateServiceModule(&content, file, service, handlerModulePrefix, httpTranscode, codecs)
generateServiceModule(&content, file, service, handlerModulePrefix, httpTranscode, codecs, compressors)
content.WriteString("\n")
}

Expand All @@ -270,7 +277,7 @@ func generateElixirFile(resp *pluginpb.CodeGeneratorResponse, file *descriptorpb
})
}

func generateServiceModule(content *strings.Builder, file *descriptorpb.FileDescriptorProto, service *descriptorpb.ServiceDescriptorProto, handlerModulePrefix string, httpTranscode bool, codecs []string) {
func generateServiceModule(content *strings.Builder, file *descriptorpb.FileDescriptorProto, service *descriptorpb.ServiceDescriptorProto, handlerModulePrefix string, httpTranscode bool, codecs []string, compressors []string) {
serverModuleName := generateServerModuleName(file, service)
serviceModuleName := generateServiceModuleName(file, service)

Expand All @@ -290,6 +297,16 @@ func generateServiceModule(content *strings.Builder, file *descriptorpb.FileDesc
}
content.WriteString("]")
}
if len(compressors) > 0 {
content.WriteString(",\n compressors: [")
for i, compressor := range compressors {
if i > 0 {
content.WriteString(", ")
}
content.WriteString(compressor)
}
content.WriteString("]")
}
content.WriteString("\n\n")

for _, method := range service.Method {
Expand Down
58 changes: 56 additions & 2 deletions cmd/protoc-gen-elixir-grpc/main_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -490,6 +490,59 @@ end
assert.Equal(t, expected, content)
})

t.Run("with compressors option", func(t *testing.T) {
fileDesc := &descriptorpb.FileDescriptorProto{
Name: ptr("data/v1/data.proto"),
Package: ptr("data.v1"),
MessageType: []*descriptorpb.DescriptorProto{
{Name: ptr("DataRequest")},
{Name: ptr("DataResponse")},
},
Service: []*descriptorpb.ServiceDescriptorProto{
{
Name: ptr("DataService"),
Method: []*descriptorpb.MethodDescriptorProto{
{
Name: ptr("GetData"),
InputType: ptr(".data.v1.DataRequest"),
OutputType: ptr(".data.v1.DataResponse"),
},
},
},
},
}

req := &pluginpb.CodeGeneratorRequest{
FileToGenerate: []string{"data/v1/data.proto"},
ProtoFile: []*descriptorpb.FileDescriptorProto{fileDesc},
SourceFileDescriptors: []*descriptorpb.FileDescriptorProto{fileDesc},
CompilerVersion: compilerVersion,
Parameter: ptr("compressors=GRPC.Compressor.Gzip"),
}

rsp := testGenerate(t, req)
assert.Nil(t, rsp.Error)
assert.Equal(t, 1, len(rsp.File))

file := rsp.File[0]
assert.Equal(t, "data/v1/data.server.pb.ex", file.GetName())

content := file.GetContent()
expected := `# Code generated by protoc-gen-elixir-grpc. DO NOT EDIT.
#
# Source: data/v1/data.proto

defmodule Data.V1.DataService.Server do
use GRPC.Server,
service: Data.V1.DataService.Service,
compressors: [GRPC.Compressor.Gzip]

defdelegate get_data(request, stream), to: Data.V1.DataService.Server.GetDataHandler, as: :handle_message
end
`
assert.Equal(t, expected, content)
})

t.Run("with all options combined", func(t *testing.T) {
fileDesc := &descriptorpb.FileDescriptorProto{
Name: ptr("store/v1/store.proto"),
Expand Down Expand Up @@ -517,7 +570,7 @@ end
ProtoFile: []*descriptorpb.FileDescriptorProto{fileDesc},
SourceFileDescriptors: []*descriptorpb.FileDescriptorProto{fileDesc},
CompilerVersion: compilerVersion,
Parameter: ptr("http_transcode=true,handler_module_prefix=MyApp.Business,codecs=GRPC.Codec.Proto,GRPC.Codec.JSON"),
Parameter: ptr("http_transcode=true,handler_module_prefix=MyApp.Business,codecs=GRPC.Codec.Proto,GRPC.Codec.JSON,compressors=GRPC.Compressor.Gzip"),
}

rsp := testGenerate(t, req)
Expand All @@ -536,7 +589,8 @@ defmodule Store.V1.StoreService.Server do
use GRPC.Server,
service: Store.V1.StoreService.Service,
http_transcode: true,
codecs: [GRPC.Codec.Proto, GRPC.Codec.JSON]
codecs: [GRPC.Codec.Proto, GRPC.Codec.JSON],
compressors: [GRPC.Compressor.Gzip]

defdelegate create_store(request, stream), to: MyApp.Business.Store.V1.StoreService.Server.CreateStoreHandler, as: :handle_message
end
Expand Down