implement gRPC rest gateway

Makefile

@@ -8,8 +8,14 @@ PATH := $(PROJECT_BIN):$(PATH)
 model-registry: build
 
 internal/ml_metadata/proto/%.pb.go: api/grpc/ml_metadata/proto/%.proto
-	protoc -I./api/grpc --go_out=./internal --go_opt=paths=source_relative \
-		--go-grpc_out=./internal --go-grpc_opt=paths=source_relative $<
+	protoc -I./api/grpc \
+		--go_out=./internal --go_opt=paths=source_relative \
+		--go-grpc_out=./internal --go-grpc_opt=paths=source_relative \
+		--grpc-gateway_out=./internal --grpc-gateway_opt logtostderr=true \
+		--grpc-gateway_opt paths=source_relative --grpc-gateway_opt generate_unbound_methods=true \
+		--openapiv2_out ./api/gen/openapiv2 --openapiv2_opt logtostderr=true --openapiv2_opt json_names_for_fields=false \
+		--openapiv2_opt generate_unbound_methods=true --openapiv2_opt output_format=yaml \
+		--openapiv2_opt preserve_rpc_order=true $<
 
 .PHONY: gen/grpc
 gen/grpc: internal/ml_metadata/proto/metadata_store.pb.go internal/ml_metadata/proto/metadata_store_service.pb.go
@@ -26,7 +32,7 @@ vet:
 
 .PHONY: clean
 clean:
-	rm -Rf ./model-registry internal/ml_metadata/proto/*.go internal/model/graph/models_gen.go
+	rm -Rf ./model-registry internal/ml_metadata/proto/*.go internal/model/graph/models_gen.go api/gen/openapiv2/ml_metadata/proto/*.yaml
 
 .PHONY: deps
 deps:
@@ -35,6 +41,8 @@ deps:
 	GOBIN=$(PROJECT_BIN) go install github.com/searKing/golang/tools/[email protected]
 	GOBIN=$(PROJECT_BIN) go install google.golang.org/protobuf/cmd/[email protected]
 	GOBIN=$(PROJECT_BIN) go install google.golang.org/grpc/cmd/[email protected]
+	GOBIN=$(PROJECT_BIN) go install github.com/grpc-ecosystem/grpc-gateway/v2/[email protected]
+	GOBIN=$(PROJECT_BIN) go install github.com/grpc-ecosystem/grpc-gateway/v2/[email protected]
 
 .PHONY: vendor
 vendor:
@@ -67,6 +75,10 @@ run/server: gen metadata.sqlite.db
 run/client: gen
 	python test/python/test_mlmetadata.py
 
+.PHONY: run/gateway
+run/gateway:
+	go run main.go gateway --logtostderr=true
+
 .PHONY: serve
 serve: build
 	./model-registry serve --logtostderr=true

api/gen/openapiv2/ml_metadata/proto/metadata_store.swagger.yaml

@@ -0,0 +1,144 @@
+swagger: "2.0"
+info:
+  title: ml_metadata/proto/metadata_store.proto
+  version: version not set
+consumes:
+  - application/json
+produces:
+  - application/json
+paths: {}
+definitions:
+  protobufAny:
+    type: object
+    properties:
+      '@type':
+        type: string
+        description: |-
+          A URL/resource name that uniquely identifies the type of the serialized
+          protocol buffer message. This string must contain at least
+          one "/" character. The last segment of the URL's path must represent
+          the fully qualified name of the type (as in
+          `path/google.protobuf.Duration`). The name should be in a canonical form
+          (e.g., leading "." is not accepted).
+
+          In practice, teams usually precompile into the binary all types that they
+          expect it to use in the context of Any. However, for URLs which use the
+          scheme `http`, `https`, or no scheme, one can optionally set up a type
+          server that maps type URLs to message definitions as follows:
+
+          * If no scheme is provided, `https` is assumed.
+          * An HTTP GET on the URL must yield a [google.protobuf.Type][]
+            value in binary format, or produce an error.
+          * Applications are allowed to cache lookup results based on the
+            URL, or have them precompiled into a binary to avoid any
+            lookup. Therefore, binary compatibility needs to be preserved
+            on changes to types. (Use versioned type names to manage
+            breaking changes.)
+
+          Note: this functionality is not currently available in the official
+          protobuf release, and it is not used for type URLs beginning with
+          type.googleapis.com. As of May 2023, there are no widely used type server
+          implementations and no plans to implement one.
+
+          Schemes other than `http`, `https` (or the empty scheme) might be
+          used with implementation specific semantics.
+    additionalProperties: {}
+    description: |-
+      `Any` contains an arbitrary serialized protocol buffer message along with a
+      URL that describes the type of the serialized message.
+
+      Protobuf library provides support to pack/unpack Any values in the form
+      of utility functions or additional generated methods of the Any type.
+
+      Example 1: Pack and unpack a message in C++.
+
+          Foo foo = ...;
+          Any any;
+          any.PackFrom(foo);
+          ...
+          if (any.UnpackTo(&foo)) {
+            ...
+          }
+
+      Example 2: Pack and unpack a message in Java.
+
+          Foo foo = ...;
+          Any any = Any.pack(foo);
+          ...
+          if (any.is(Foo.class)) {
+            foo = any.unpack(Foo.class);
+          }
+          // or ...
+          if (any.isSameTypeAs(Foo.getDefaultInstance())) {
+            foo = any.unpack(Foo.getDefaultInstance());
+          }
+
+       Example 3: Pack and unpack a message in Python.
+
+          foo = Foo(...)
+          any = Any()
+          any.Pack(foo)
+          ...
+          if any.Is(Foo.DESCRIPTOR):
+            any.Unpack(foo)
+            ...
+
+       Example 4: Pack and unpack a message in Go
+
+           foo := &pb.Foo{...}
+           any, err := anypb.New(foo)
+           if err != nil {
+             ...
+           }
+           ...
+           foo := &pb.Foo{}
+           if err := any.UnmarshalTo(foo); err != nil {
+             ...
+           }
+
+      The pack methods provided by protobuf library will by default use
+      'type.googleapis.com/full.type.name' as the type URL and the unpack
+      methods only use the fully qualified type name after the last '/'
+      in the type URL, for example "foo.bar.com/x/y.z" will yield type
+      name "y.z".
+
+      JSON
+      ====
+      The JSON representation of an `Any` value uses the regular
+      representation of the deserialized, embedded message, with an
+      additional field `@type` which contains the type URL. Example:
+
+          package google.profile;
+          message Person {
+            string first_name = 1;
+            string last_name = 2;
+          }
+
+          {
+            "@type": "type.googleapis.com/google.profile.Person",
+            "firstName": <string>,
+            "lastName": <string>
+          }
+
+      If the embedded message type is well-known and has a custom JSON
+      representation, that representation will be embedded adding a field
+      `value` which holds the custom JSON in addition to the `@type`
+      field. Example (for message [google.protobuf.Duration][]):
+
+          {
+            "@type": "type.googleapis.com/google.protobuf.Duration",
+            "value": "1.212s"
+          }
+  rpcStatus:
+    type: object
+    properties:
+      code:
+        type: integer
+        format: int32
+      message:
+        type: string
+      details:
+        type: array
+        items:
+          type: object
+          $ref: '#/definitions/protobufAny'