feat!: replace Pyro4/ZMQ transport with gRPC

.github/wordlist.txt

@@ -45,6 +45,7 @@ gnutls
 googlegroups
 gpg
 GPIO
+gRPC
 GStreamer
 hombourger
 homekit

.github/workflows/proto.yml

@@ -0,0 +1,36 @@
+# ---------------------------------------------------------------------------
+# Verify mtda.proto is valid and the build step can generate stubs from it
+# ---------------------------------------------------------------------------
+#
+# This software is a part of MTDA.
+# Copyright (C) 2026 Siemens AG
+#
+# ---------------------------------------------------------------------------
+# SPDX-License-Identifier: MIT
+# ---------------------------------------------------------------------------
+
+name: Proto stubs
+
+on:
+  pull_request:
+    paths:
+      - 'mtda/grpc/mtda.proto'
+
+jobs:
+  check-stubs:
+    name: Verify stubs can be generated from mtda.proto
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install grpcio-tools
+        run: pip3 install grpcio-tools
+
+      - name: Generate stubs
+        run: |
+          python3 -m grpc_tools.protoc \
+            -I mtda/grpc \
+            --python_out=mtda/grpc \
+            --grpc_python_out=mtda/grpc \
+            mtda/grpc/mtda.proto

.gitignore

@@ -5,6 +5,8 @@
 *.changes
 *.img
 *.pyc
+*_pb2.py
+*_pb2_grpc.py
 *.swp
 build
 cip-core

CONTRIBUTING.md

@@ -13,6 +13,12 @@ Contribution Checklist
 
 - follow the existing coding style (run `pycodestyle` on changed files) [**required**]
 
+- if `mtda/grpc/mtda.proto` is modified, the Python stubs
+  (`mtda_pb2.py`, `mtda_pb2_grpc.py`) are **not** committed — they are
+  generated automatically during `python setup.py build` / `pip install`.
+  The CI will verify that `grpc_tools.protoc` can still consume the updated
+  `.proto` without errors.
+
 - add the required copyright header to each new file introduced, see
   [licensing information](COPYING) [**required**]
 

configs/docker.ini

@@ -18,9 +18,9 @@ debug = 2
 # ---------------------------------------------------------------------------
 # Remote settings
 # ---------------------------------------------------------------------------
+# Set "control" to the TCP/IP port number for the gRPC control interface
 [remote]
 control = 5556
-console = 5557
 host    = localhost
 
 # ---------------------------------------------------------------------------

configs/qemu.ini

@@ -24,9 +24,9 @@ variant=qemu
 # ---------------------------------------------------------------------------
 # Remote settings
 # ---------------------------------------------------------------------------
+# Set "control" to the TCP/IP port number for the gRPC control interface
 [remote]
 control = 5556
-console = 5557
 host    = localhost
 
 # ---------------------------------------------------------------------------

debian/.gitignore

@@ -10,4 +10,5 @@ mtda-docker
 mtda-kvm
 mtda-pytest
 mtda-service
+mtda-systemd-helper
 mtda-www

debian/control

@@ -6,6 +6,7 @@ Build-Depends: debhelper (>=10) | dh-systemd,
                dh-python,
                libpython3-all-dev,
                python3-all-dev:any,
+               python3-grpc-tools,
                python3-setuptools,
                python3-sphinx:native <!nodoc>,
                python3-sphinx-rtd-theme:native <!nodoc>
@@ -32,7 +33,6 @@ Depends: mtda-common,
          python3-systemd,
          python3-usb,
          python3-zeroconf,
-         python3-zmq,
          python3-zstandard,
          usbrelay,
          ${misc:Depends},
@@ -82,7 +82,7 @@ Package: mtda-common
 Architecture: all
 Multi-Arch: foreign
 Depends: python3:any (>= 3.7~),
-         python3-pyro5 | python3-pyro4
+         python3-grpcio
 Description: common modules for Multi-Tenant Device Access
  Modules shared between the service and the client.
 

docs/config.rst

@@ -83,19 +83,13 @@ General settings
       ``pduclient``, ``qemu``, ``shellcmd`` and ``usbrelay``.
 
 * ``remote``: section [optional]
-    Specify the host and ports to connect to when using a MTDA client (such as
+    Specify the host and port to connect to when using a MTDA client (such as
     ``mtda-cli``).
 
   * ``control``: integer [optional]
-      Remote port listening for control commands (defaults to ``5556``).
-
-  * ``console``: integer [optional]
-      Remote port to connect to in order to get console messages (defaults to
-      ``5557``).
-
-  * ``data``: integer [optional]
-      Remote port for data transfers between the client and agent (defaults to
-      ``0`` for a dynamic port assignment).
+      Remote port listening for gRPC requests (defaults to ``5556``). All
+      traffic — control commands, console streaming and data transfers — flows
+      over this single port.
 
   * ``host``: string [optional]
       Remote host name or ip to connect to as a client to interact with the

docs/usage.rst

@@ -10,7 +10,7 @@ command. A remote agent may be specified on the command line using the
 The remote may be alternatively specified in the ``[remote]]`` section
 of the local configuration file.
 
-Power commands 
+Power commands
 ~~~~~~~~~~~~~~
 
 When MTDA is configured with a ``[power]`` control block in its configuration,
@@ -168,15 +168,15 @@ Keyboard
 ~~~~~~~~
 
 The assist board has the capability. to act as keyboard to the DUT,general usage is
-``mtda-cli keyboard write characters....`` Some special characters are supported and 
+``mtda-cli keyboard write characters....`` Some special characters are supported and
 need to be enclosed between < and >
 
 For instance: ``mtda-cli keyboard write "<down><enter>hello world<enter>"``
 
 .. list-table:: Special Keys
    :widths: 20 80
-   :header-rows: 1   
-   
+   :header-rows: 1
+
    * - Supported Special Keys
      - String
    * - Backspace

meta-isar/recipes-python/mtda/mtda_git.bb

@@ -62,6 +62,8 @@ do_gen_working_repo() {
 	for file in ${MTDA_FILES}; do
 		cp -a ${LAYERDIR_mtda}/../$file ${S}/
 	done
+	# delete auto-generated files as they need to be re-generated on building
+	find ${S} -name 'mtda_pb2*.py' -delete
 	rm -f ${S}/debian/source/format
 }
 do_gen_working_repo[cleandirs] += "${S}"

mtda-cli

@@ -43,11 +43,13 @@ class AppOutput(ScreenOutput):
 
         if len(event) != 6:
             return
-        if event[0] != 'STORAGE' and event[1] != 'WRITING':
+        if event[0] != 'STORAGE' or event[1] != 'WRITING':
             return
 
         app = self.app
         image = app.imgname
+        if image is None:
+            return
         # If the backend has information about the bytes to write (i.e. the mapped bytes)
         # read and total refer to the output stream writes (without seeks) and mapped bytes.
         bytes_read = int(event[2])
@@ -81,6 +83,7 @@ class Application:
         self.remote = None
         self.exiting = False
         self.channel = "console"
+        self.imgname = None
         self.screen = AppOutput(self)
 
     def client(self):
@@ -137,10 +140,12 @@ class Application:
 
         client.console_init()
 
-        # Get prefix key
+        # Get prefix key (as bytes for comparison with getkey() return value)
         prefix_key = None
         if sys.stdin.isatty():
-            prefix_key = client.console_prefix_key()
+            pk = client.console_prefix_key()
+            if pk is not None:
+                prefix_key = pk.encode("utf-8") if isinstance(pk, str) else pk
 
         # Input loop
         while self.exiting is False:
@@ -158,6 +163,8 @@ class Application:
     def console_menukey(self, c):
         client = self.agent
         server = self.client()
+        if isinstance(c, bytes):
+            c = c.decode("latin-1")
         if c == 'a':
             status = server.target_lock()
             if status is True:
@@ -252,7 +259,7 @@ class Application:
             f"\r\n*** console buffer posted to {r.text} ***\r\n")
 
     def console_prompt(self, args):
-        data = self.client().console_prompt(args.prompt)
+        data = self.client().console_prompt(args.prompt_str)
         if data is not None:
             sys.stdout.write(data)
             sys.stdout.flush()

mtda-service

@@ -12,6 +12,7 @@
 
 # System imports
 import argparse
+import concurrent.futures
 import lockfile
 import netifaces
 import os
@@ -22,16 +23,15 @@ import socket
 import zeroconf
 from systemd import daemon as sd
 
+# gRPC
+import grpc
+
 # Local imports
 from mtda.main import MultiTenantDeviceAccess
+from mtda.grpc import mtda_pb2_grpc
+from mtda.grpc.servicer import MtdaServicer
 import mtda.constants as CONSTS
 
-# Pyro
-try:
-    from Pyro5.compatibility import Pyro4
-except ImportError:
-    import Pyro4
-
 
 class Application:
 
@@ -79,11 +79,13 @@ class Application:
         if status is False:
             return False
 
-        # Start our RPC server
-        Pyro4.config.HOST = "0.0.0.0"
-        Pyro4.config.SERIALIZER = "marshal"
-        daemon = Pyro4.Daemon(port=self.agent.ctrlport)
-        daemon.register(self.agent, objectId="mtda.main")
+        # Start our gRPC server
+        self._grpc_server = grpc.server(
+            concurrent.futures.ThreadPoolExecutor(max_workers=10))
+        mtda_pb2_grpc.add_MtdaServiceServicer_to_server(
+            MtdaServicer(self.agent), self._grpc_server)
+        self._grpc_server.add_insecure_port(f'[::]:{self.agent.ctrlport}')
+        self._grpc_server.start()
 
         # Initialize ZeroConf
         interfaces = zeroconf.InterfaceChoice.All
@@ -111,14 +113,16 @@ class Application:
 
         try:
             sd.notify('READY=1')
-            daemon.requestLoop()
+            self._grpc_server.wait_for_termination()
         except KeyboardInterrupt:
             self.stop()
         return True
 
     def stop(self, signum=0, frame=None):
         if self.zerosrv is not None:
             self.zeroconf.unregister_service(self.zerosrv)
+        if hasattr(self, '_grpc_server'):
+            self._grpc_server.stop(grace=5)
         if self.agent is not None:
             self.agent.stop()
         sys.exit(signum)