Add option use-json-names to allow using json_name globally

README.md

@@ -12,7 +12,7 @@ go get github.com/GoogleCloudPlatform/protoc-gen-bq-schema
 ```
 
 ## Usage
- protoc --bq-schema\_out=path/to/outdir \[--bq-schema_opt=single-message\] foo.proto
+ protoc --bq-schema\_out=path/to/outdir \[--bq-schema_opt=single-message,use-json-names\] foo.proto
 
 `protoc` and `protoc-gen-bq-schema` commands must be found in $PATH.
 
@@ -72,6 +72,9 @@ The message `foo.Baz` is ignored because it doesn't have option `gen_bq_schema.b
 `protoc --bq-schema_out=. --bq-schema_opt=single-message single_message.proto` will generate a file named `foo/single_message.schema`.
 The message `foo.Baz` is also ignored because it is not the first message in the file.
 
+`protoc --bq-schema_out=. --bq-schema_opt=use-json-names foo.proto` will generate a schema whose fields are named using `json_name`.
+This is equivalent to tagging every message as `use_json_names = true` and provided for convenience.
+
 
 ### Support for PolicyTags
 `protoc-gen-bq-schema` now supports [policyTags](https://cloud.google.com/bigquery/docs/column-level-security-intro). 

main.go

@@ -53,6 +53,8 @@ var (
 		comments: make(map[string]Comments),
 		path:     make(map[string]string),
 	}
+
+	globallyUseJsonNames = false
 )
 
 // Field describes the schema of a field in BigQuery.
@@ -238,7 +240,7 @@ func convertField(
 	field := &Field{
 		Name: desc.GetName(),
 	}
-	if msgOpts.GetUseJsonNames() && desc.GetJsonName() != "" {
+	if (msgOpts.GetUseJsonNames() || globallyUseJsonNames) && desc.GetJsonName() != "" {
 		field.Name = desc.GetJsonName()
 	}
 
@@ -505,7 +507,21 @@ func handleSingleMessageOpt(file *descriptor.FileDescriptorProto, requestParam s
 	})
 }
 
+// handleUseJsonNamesOpt handles --bq-schema_opt=use-json-names in protoc params.
+// providing that param tells protoc-gen-bq-schema to always use a field's json_name
+// as the corresponding BigQuery column name.
+// it is equivalent to setting the option use_json_name as true to every message.
+func handleUseJsonNamesOpt(requestParam string) {
+	if !strings.Contains(requestParam, "use-json-names") {
+		return
+	}
+
+	globallyUseJsonNames = true
+}
+
 func convert(req *plugin.CodeGeneratorRequest) (*plugin.CodeGeneratorResponse, error) {
+	handleUseJsonNamesOpt(req.GetParameter())
+
 	generateTargets := make(map[string]bool)
 	for _, file := range req.GetFileToGenerate() {
 		generateTargets[file] = true

plugin_test.go

@@ -504,3 +504,37 @@ func TestExtraFields(t *testing.T) {
 			]`,
 		})
 }
+
+func TestGloballyUseJsonNamesOpt(t *testing.T) {
+	globallyUseJsonNames = true
+	testConvert(t, `
+			file_to_generate: "foo.proto"
+			proto_file <
+				name: "foo.proto"
+				package: "example_package.nested"
+				message_type <
+					name: "FooProto"
+					field < name: "str" number: 1 type: TYPE_STRING label: LABEL_OPTIONAL json_name: "someJsonSpecificName" >
+					field <
+						name: "nested_message" number: 2 type: TYPE_MESSAGE label: LABEL_OPTIONAL
+						type_name: ".example_package.nested.FooProto.Nested" json_name: "nestedMessage"
+					>
+					nested_type <
+						name: "Nested"
+						field < name: "some_field" number: 1 type: TYPE_STRING label: LABEL_OPTIONAL json_name: "someField" >
+					>
+					options < [gen_bq_schema.bigquery_opts] <table_name: "foo_table"> >
+				>
+			>
+		`,
+		map[string]string{
+			"example_package/nested/foo_table.schema": `[
+				{ "name": "someJsonSpecificName", "type": "STRING", "mode": "NULLABLE" },
+				{
+					"name": "nestedMessage", "type": "RECORD", "mode": "NULLABLE",
+					"fields": [{ "name": "someField", "type": "STRING", "mode": "NULLABLE" }]
+				}
+			]`,
+		})
+	globallyUseJsonNames = false
+}