Build json template

README.md

@@ -51,7 +51,7 @@ $ protokaf produce -h
 ### Examples
 This proto file will be used in the examples below. 
 
-`api/example.ptoto`
+`api/example.proto`
 ```protobuf
 syntax = "proto3";
 
@@ -127,6 +127,44 @@ $ protokaf produce HelloRequest -t test -d '{"name": "Alice", "age": 11}'
 $ protokaf produce --template-functions-print
 ```
 
+## Build json template by proto file
+This can be useful for creating body for produce command
+```sh
+$ protokaf build HelloRequest --proto internal/proto/testdata/example.proto
+```
+For proto file
+```protobuf
+syntax = "proto3";
+
+package example;
+
+message HelloRequest {
+  enum Status {
+    PENDING = 0;
+    COMPLETED = 1;
+  }
+
+  string name = 1;
+  int32 age = 2;
+  optional float amount = 4;
+  Status status = 5;
+  repeated string keys = 6;
+}
+```
+command will print
+```json
+{
+  "name": "",
+  "age": 0,
+  "amount": 0,
+  "status": "PENDING",
+  "keys": [
+    ""
+  ]
+}
+
+```
+
 ## Consume
 ### Help
 ```sh

cmd/cmd_build_test.go

@@ -0,0 +1,77 @@
+package cmd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_NewBuildCmd(t *testing.T) {
+	cmd := NewBuildCmd()
+	NewFlags(cmd).Init()
+	cmd.SetArgs([]string{"ExampleMessage", "--proto", "../internal/proto/testdata/types.proto"})
+
+	expected := `{
+  "int32Field": 0,
+  "int64Field": "0",
+  "uint32Field": 0,
+  "uint64Field": "0",
+  "sint32Field": 0,
+  "sint64Field": "0",
+  "fixed32Field": 0,
+  "fixed64Field": "0",
+  "sfixed32Field": 0,
+  "sfixed64Field": "0",
+  "floatField": 0,
+  "doubleField": 0,
+  "boolField": true,
+  "stringField": "",
+  "bytesField": "",
+  "enumField": "UNKNOWN",
+  "messageField": {
+    "nestedInt32": 0,
+    "nestedString": ""
+  },
+  "repeatedInt32Field": [
+    0
+  ],
+  "repeatedStringField": [
+    ""
+  ],
+  "mapStringInt32Field": {
+    "": 0
+  },
+  "mapInt32MessageField": {
+    "0": {
+      "nestedInt32": 0,
+      "nestedString": ""
+    }
+  },
+  "option1": 0,
+  "anyField": null,
+  "timestampField": "1970-01-01T00:00:00Z",
+  "durationField": "0s",
+  "structField": {
+    "": null
+  },
+  "valueField": null,
+  "listValueField": [
+    null
+  ],
+  "boolValueField": true,
+  "bytesValueField": null,
+  "doubleValueField": 0,
+  "floatValueField": 0,
+  "int32ValueField": 0,
+  "int64ValueField": "0",
+  "stringValueField": "",
+  "uint32ValueField": 0,
+  "uint64ValueField": "0"
+}`
+
+	stdout, stderr, err := getCommandOut(t, cmd)
+
+	require.Nil(t, err)
+	require.Equal(t, "", stderr)
+	require.Contains(t, stdout, expected)
+}

cmd/cmd_buld.go

@@ -0,0 +1,110 @@
+package cmd
+
+import (
+	"github.com/golang/protobuf/jsonpb"
+	"github.com/jhump/protoreflect/desc"
+	"github.com/jhump/protoreflect/dynamic"
+	"github.com/spf13/cobra"
+	"google.golang.org/protobuf/types/descriptorpb"
+	"google.golang.org/protobuf/types/known/anypb"
+)
+
+func NewBuildCmd() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "build <MessageName>",
+		Short: "Build json by proto message",
+		Args:  messageNameRequired,
+		RunE: func(cmd *cobra.Command, args []string) (err error) {
+			// parse protofiles & create proto object
+			p, err := parseProtofiles()
+			if err != nil {
+				return
+			}
+
+			messageDescriptor, err := findMessage(p, args[0])
+			if err != nil {
+				return
+			}
+
+			msg := buildMessage(dynamic.NewMessage(messageDescriptor))
+
+			b, err := msg.MarshalJSONPB(&jsonpb.Marshaler{
+				EmitDefaults: true,
+				Indent:       "  ",
+			})
+			if err != nil {
+				return
+			}
+
+			cmd.Println(string(b))
+
+			return
+		},
+	}
+
+	return cmd
+}
+
+func buildMessage(message *dynamic.Message) *dynamic.Message {
+	for _, field := range message.GetMessageDescriptor().GetFields() {
+		switch {
+		case field.IsRepeated():
+			message.SetField(field, []interface{}{buildDefaultValue(field)})
+		case field.IsMap():
+			message.SetField(
+				field,
+				map[interface{}]interface{}{
+					buildDefaultValue(field.GetMapKeyType()): buildDefaultValue(field.GetMapValueType()),
+				},
+			)
+		case field.GetOneOf() != nil:
+			oneOfField := field.GetOneOf().GetChoices()[0]
+			message.SetField(oneOfField, buildDefaultValue(oneOfField))
+		default:
+			message.SetField(field, buildDefaultValue(field))
+		}
+	}
+
+	return message
+}
+
+func buildDefaultValue(field *desc.FieldDescriptor) interface{} {
+	switch field.GetType() {
+	case descriptorpb.FieldDescriptorProto_TYPE_FIXED32,
+		descriptorpb.FieldDescriptorProto_TYPE_UINT32:
+		return uint32(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_SFIXED32,
+		descriptorpb.FieldDescriptorProto_TYPE_INT32,
+		descriptorpb.FieldDescriptorProto_TYPE_SINT32:
+		return int32(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_FIXED64,
+		descriptorpb.FieldDescriptorProto_TYPE_UINT64:
+		return uint64(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_SFIXED64,
+		descriptorpb.FieldDescriptorProto_TYPE_INT64,
+		descriptorpb.FieldDescriptorProto_TYPE_SINT64:
+		return int64(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_FLOAT:
+		return float32(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_DOUBLE:
+		return float64(0)
+	case descriptorpb.FieldDescriptorProto_TYPE_BOOL:
+		return true
+	case descriptorpb.FieldDescriptorProto_TYPE_BYTES:
+		return []byte(nil)
+	case descriptorpb.FieldDescriptorProto_TYPE_STRING:
+		return ""
+	case descriptorpb.FieldDescriptorProto_TYPE_ENUM:
+		return field.GetEnumType().GetValues()[0].GetNumber()
+	case descriptorpb.FieldDescriptorProto_TYPE_MESSAGE:
+		if field.GetMessageType().GetFullyQualifiedName() == "google.protobuf.Any" {
+			val, _ := anypb.New(nil)
+
+			return val
+		}
+
+		return buildMessage(dynamic.NewMessage(field.GetMessageType()))
+	}
+
+	return nil
+}

cmd/cmd_root.go

@@ -85,6 +85,7 @@ func NewRootCmd() *cobra.Command {
 		NewProduceCmd(),
 		NewConsumeCmd(),
 		NewListCmd(),
+		NewBuildCmd(),
 	)
 
 	return cmd

go.mod

@@ -16,6 +16,7 @@ require (
 	github.com/uber/jaeger-client-go v2.29.1+incompatible
 	github.com/xdg/scram v1.0.3
 	go.uber.org/zap v1.18.1
+	google.golang.org/protobuf v1.33.0
 )
 
 require (
@@ -55,7 +56,6 @@ require (
 	golang.org/x/sys v0.19.0 // indirect
 	golang.org/x/text v0.14.0 // indirect
 	google.golang.org/genproto v0.0.0-20210602131652-f16073e35f0c // indirect
-	google.golang.org/protobuf v1.33.0 // indirect
 	gopkg.in/ini.v1 v1.62.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

internal/proto/testdata/types.proto

@@ -0,0 +1,80 @@
+syntax = "proto3";
+
+package example;
+
+import "google/protobuf/any.proto";
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/duration.proto";
+import "google/protobuf/struct.proto";
+import "google/protobuf/wrappers.proto";
+
+// Enum definition
+enum ExampleEnum {
+    UNKNOWN = 0;
+    OPTION_ONE = 1;
+    OPTION_TWO = 2;
+}
+
+// Message definition
+message ExampleMessage {
+    // Scalar types
+    int32 int32_field = 1;
+    int64 int64_field = 2;
+    uint32 uint32_field = 3;
+    uint64 uint64_field = 4;
+    sint32 sint32_field = 5;
+    sint64 sint64_field = 6;
+    fixed32 fixed32_field = 7;
+    fixed64 fixed64_field = 8;
+    sfixed32 sfixed32_field = 9;
+    sfixed64 sfixed64_field = 10;
+    float float_field = 11;
+    double double_field = 12;
+    bool bool_field = 13;
+    string string_field = 14;
+    bytes bytes_field = 15;
+
+    // Enum type
+    ExampleEnum enum_field = 16;
+
+    // Nested message
+    message NestedMessage {
+        int32 nested_int32 = 1;
+        string nested_string = 2;
+    }
+
+    // Message type
+    NestedMessage message_field = 17;
+
+    // Repeated fields
+    repeated int32 repeated_int32_field = 18;
+    repeated string repeated_string_field = 19;
+
+    // Map fields
+    map<string, int32> map_string_int32_field = 20;
+    map<int32, NestedMessage> map_int32_message_field = 21;
+
+    // Oneof field
+    oneof my_oneof {
+        int32 option1 = 22;
+        string option2 = 23;
+        NestedMessage option3 = 24;
+    }
+
+    // Well-known types
+    google.protobuf.Any any_field = 25;
+    google.protobuf.Timestamp timestamp_field = 26;
+    google.protobuf.Duration duration_field = 27;
+    google.protobuf.Struct struct_field = 28;
+    google.protobuf.Value value_field = 29;
+    google.protobuf.ListValue list_value_field = 30;
+    google.protobuf.BoolValue bool_value_field = 31;
+    google.protobuf.BytesValue bytes_value_field = 32;
+    google.protobuf.DoubleValue double_value_field = 33;
+    google.protobuf.FloatValue float_value_field = 34;
+    google.protobuf.Int32Value int32_value_field = 35;
+    google.protobuf.Int64Value int64_value_field = 36;
+    google.protobuf.StringValue string_value_field = 37;
+    google.protobuf.UInt32Value uint32_value_field = 38;
+    google.protobuf.UInt64Value uint64_value_field = 39;
+}