feat(gateway): gRPC proto + generated stubs (C4)

ingestor/proto/opc_gateway.proto

@@ -0,0 +1,18 @@
+syntax = "proto3";
+package opcgateway;
+
+service OpcGateway {
+  rpc ReadTag(ReadTagRequest) returns (ReadTagResponse);
+}
+message ReadTagRequest {
+  string server_id = 1;
+  string addr = 2;
+  string data_type = 3;
+}
+message ReadTagResponse {
+  string value = 1;
+  string opc_status_code = 2;
+  string source_timestamp = 3;
+  string server_timestamp = 4;
+  bool persisted = 5;
+}

ingestor/proto/opc_gateway_pb2.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# NO CHECKED-IN PROTOBUF GENCODE
+# source: opc_gateway.proto
+# Protobuf Python Version: 7.35.0
+"""Generated protocol buffer code."""
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import descriptor_pool as _descriptor_pool
+from google.protobuf import runtime_version as _runtime_version
+from google.protobuf import symbol_database as _symbol_database
+from google.protobuf.internal import builder as _builder
+_runtime_version.ValidateProtobufRuntimeVersion(
+    _runtime_version.Domain.PUBLIC,
+    7,
+    35,
+    0,
+    '',
+    'opc_gateway.proto'
+)
+# @@protoc_insertion_point(imports)
+
+_sym_db = _symbol_database.Default()
+
+
+
+
+DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x11opc_gateway.proto\x12\nopcgateway\"D\n\x0eReadTagRequest\x12\x11\n\tserver_id\x18\x01 \x01(\t\x12\x0c\n\x04\x61\x64\x64r\x18\x02 \x01(\t\x12\x11\n\tdata_type\x18\x03 \x01(\t\"\x80\x01\n\x0fReadTagResponse\x12\r\n\x05value\x18\x01 \x01(\t\x12\x17\n\x0fopc_status_code\x18\x02 \x01(\t\x12\x18\n\x10source_timestamp\x18\x03 \x01(\t\x12\x18\n\x10server_timestamp\x18\x04 \x01(\t\x12\x11\n\tpersisted\x18\x05 \x01(\x08\x32P\n\nOpcGateway\x12\x42\n\x07ReadTag\x12\x1a.opcgateway.ReadTagRequest\x1a\x1b.opcgateway.ReadTagResponseb\x06proto3')
+
+_globals = globals()
+_builder.BuildMessageAndEnumDescriptors(DESCRIPTOR, _globals)
+_builder.BuildTopDescriptorsAndMessages(DESCRIPTOR, 'opc_gateway_pb2', _globals)
+if not _descriptor._USE_C_DESCRIPTORS:
+  DESCRIPTOR._loaded_options = None
+  _globals['_READTAGREQUEST']._serialized_start=33
+  _globals['_READTAGREQUEST']._serialized_end=101
+  _globals['_READTAGRESPONSE']._serialized_start=104
+  _globals['_READTAGRESPONSE']._serialized_end=232
+  _globals['_OPCGATEWAY']._serialized_start=234
+  _globals['_OPCGATEWAY']._serialized_end=314
+# @@protoc_insertion_point(module_scope)

ingestor/proto/opc_gateway_pb2_grpc.py

@@ -0,0 +1,97 @@
+# Generated by the gRPC Python protocol compiler plugin. DO NOT EDIT!
+"""Client and server classes corresponding to protobuf-defined services."""
+import grpc
+import warnings
+
+from . import opc_gateway_pb2 as opc__gateway__pb2
+
+GRPC_GENERATED_VERSION = '1.82.1'
+GRPC_VERSION = grpc.__version__
+_version_not_supported = False
+
+try:
+    from grpc._utilities import first_version_is_lower
+    _version_not_supported = first_version_is_lower(GRPC_VERSION, GRPC_GENERATED_VERSION)
+except ImportError:
+    _version_not_supported = True
+
+if _version_not_supported:
+    raise RuntimeError(
+        f'The grpc package installed is at version {GRPC_VERSION},'
+        + ' but the generated code in opc_gateway_pb2_grpc.py depends on'
+        + f' grpcio>={GRPC_GENERATED_VERSION}.'
+        + f' Please upgrade your grpc module to grpcio>={GRPC_GENERATED_VERSION}'
+        + f' or downgrade your generated code using grpcio-tools<={GRPC_VERSION}.'
+    )
+
+
+class OpcGatewayStub:
+    """Missing associated documentation comment in .proto file."""
+
+    def __init__(self, channel):
+        """Constructor.
+
+        Args:
+            channel: A grpc.Channel.
+        """
+        self.ReadTag = channel.unary_unary(
+                '/opcgateway.OpcGateway/ReadTag',
+                request_serializer=opc__gateway__pb2.ReadTagRequest.SerializeToString,
+                response_deserializer=opc__gateway__pb2.ReadTagResponse.FromString,
+                _registered_method=True)
+
+
+class OpcGatewayServicer:
+    """Missing associated documentation comment in .proto file."""
+
+    def ReadTag(self, request, context):
+        """Missing associated documentation comment in .proto file."""
+        context.set_code(grpc.StatusCode.UNIMPLEMENTED)
+        context.set_details('Method not implemented!')
+        raise NotImplementedError('Method not implemented!')
+
+
+def add_OpcGatewayServicer_to_server(servicer, server):
+    rpc_method_handlers = {
+            'ReadTag': grpc.unary_unary_rpc_method_handler(
+                    servicer.ReadTag,
+                    request_deserializer=opc__gateway__pb2.ReadTagRequest.FromString,
+                    response_serializer=opc__gateway__pb2.ReadTagResponse.SerializeToString,
+            ),
+    }
+    generic_handler = grpc.method_handlers_generic_handler(
+            'opcgateway.OpcGateway', rpc_method_handlers)
+    server.add_generic_rpc_handlers((generic_handler,))
+    server.add_registered_method_handlers('opcgateway.OpcGateway', rpc_method_handlers)
+
+
+ # This class is part of an EXPERIMENTAL API.
+class OpcGateway:
+    """Missing associated documentation comment in .proto file."""
+
+    @staticmethod
+    def ReadTag(request,
+            target,
+            options=(),
+            channel_credentials=None,
+            call_credentials=None,
+            insecure=False,
+            compression=None,
+            wait_for_ready=None,
+            timeout=None,
+            metadata=None):
+        return grpc.experimental.unary_unary(
+            request,
+            target,
+            '/opcgateway.OpcGateway/ReadTag',
+            opc__gateway__pb2.ReadTagRequest.SerializeToString,
+            opc__gateway__pb2.ReadTagResponse.FromString,
+            options,
+            channel_credentials,
+            insecure,
+            call_credentials,
+            compression,
+            wait_for_ready,
+            timeout,
+            metadata,
+            _registered_method=True)

pyproject.toml

@@ -23,6 +23,7 @@ exclude = [
     "*.pyc",
     ".pytest_cache",
     "htmlcov",
+    "ingestor/proto/*_pb2*.py",
 ]
 
 [tool.ruff.lint]

tests/unit/proto/test_proto.py

@@ -0,0 +1,36 @@
+from ingestor.proto import opc_gateway_pb2, opc_gateway_pb2_grpc
+
+
+def test_read_tag_request_roundtrip():
+    req = opc_gateway_pb2.ReadTagRequest(server_id='s1', addr='ns=2;s=Tag1', data_type='Float')
+
+    data = req.SerializeToString()
+    parsed = opc_gateway_pb2.ReadTagRequest()
+    parsed.ParseFromString(data)
+
+    assert parsed.server_id == 's1'
+    assert parsed.addr == 'ns=2;s=Tag1'
+    assert parsed.data_type == 'Float'
+
+
+def test_read_tag_response_roundtrip():
+    resp = opc_gateway_pb2.ReadTagResponse(
+        value='42.0',
+        opc_status_code='Good',
+        source_timestamp='2026-07-14T00:00:00Z',
+        server_timestamp='2026-07-14T00:00:01Z',
+        persisted=True,
+    )
+
+    data = resp.SerializeToString()
+    parsed = opc_gateway_pb2.ReadTagResponse()
+    parsed.ParseFromString(data)
+
+    assert parsed.value == '42.0'
+    assert parsed.opc_status_code == 'Good'
+    assert parsed.persisted is True
+
+
+def test_grpc_stub_module_loads():
+    assert hasattr(opc_gateway_pb2_grpc, 'OpcGatewayStub')
+    assert hasattr(opc_gateway_pb2_grpc, 'OpcGatewayServicer')