From 02272863967094357582454b4885d09f7e02dd37 Mon Sep 17 00:00:00 2001
From: Andreas Berthoud <andreasberthoud@gmail.com>
Date: Tue, 6 Jul 2021 18:28:35 +0200
Subject: [PATCH] backend: Add basic structure

---
 .gitignore          |  1 +
 backend/__init__.py | 36 ++++++++++++++++++++++++++
 backend/command.py  | 62 +++++++++++++++++++++++++++++++++++++++++++++
 backend/runsever.py |  3 +++
 requirements.txt    |  1 +
 5 files changed, 103 insertions(+)
 create mode 100644 backend/__init__.py
 create mode 100644 backend/command.py
 create mode 100644 backend/runsever.py

diff --git a/.gitignore b/.gitignore
index 1ee3cdf..96189e7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -64,3 +64,4 @@ Debug/
 Release/
 .vscode/
 venv*/
+*.pyc
diff --git a/backend/__init__.py b/backend/__init__.py
new file mode 100644
index 0000000..68d6812
--- /dev/null
+++ b/backend/__init__.py
@@ -0,0 +1,36 @@
+import os
+from logging.config import dictConfig
+
+from flask_api import FlaskAPI
+
+from . import command
+
+
+def create_app() -> FlaskAPI:
+    app = FlaskAPI(__name__)
+    app.register_blueprint(command.bp)
+
+    dictConfig(
+        {
+            "version": 1,
+            "formatters": {
+                "default": {
+                    "format": "[%(asctime)s] %(levelname)s in %(module)s: %(message)s",
+                },
+            },
+            "handlers": {
+                "wsgi": {
+                    "class": "logging.StreamHandler",
+                    "stream": "ext://flask.logging.wsgi_errors_stream",
+                    "formatter": "default",
+                },
+            },
+            "root": {"level": "INFO", "handlers": ["wsgi"]},
+        },
+    )
+
+    if os.environ.get("WERKZEUG_RUN_MAIN") != "true":
+        # prevent from be called twice in debug mode
+        command.start_backgroup_process()
+
+    return app
diff --git a/backend/command.py b/backend/command.py
new file mode 100644
index 0000000..a9d3398
--- /dev/null
+++ b/backend/command.py
@@ -0,0 +1,62 @@
+import atexit
+import logging
+import os
+import time
+from multiprocessing import Process
+from multiprocessing import Queue
+from typing import Optional
+
+from flask import Response
+from flask import blueprints
+from flask import request
+from flask_api import status
+
+bp = blueprints.Blueprint("command", __name__)
+
+_process: Optional[Process] = None
+_queue: Queue = Queue()
+_logger = logging.getLogger(__name__)
+
+
+@bp.route("/command", methods=["POST", "GET"])
+def command():
+    logger = logging.getLogger("test")
+    command_id = request.args.get("command-id")
+
+    if _queue is not None and command_id is not None:
+        logger.info(f"put in queue: {command_id}")
+        _queue.put(command_id)
+
+    return Response(status=status.HTTP_200_OK)
+
+
+def _end_running_process():
+    if _process is not None:
+        _process.kill()
+
+
+def poll_from_usb(queue: Queue):
+    logging.basicConfig(
+        level=logging.DEBUG,
+        format="[%(asctime)s] [%(levelname)-8s] --- %(message)s",
+    )
+    logger = logging.getLogger("poll_from_usb")
+    counter = 1
+    while True:
+        logger.info(f"Ping {counter} {os.getpid()}")
+        counter += 1
+        time.sleep(1)
+
+        if queue is not None:
+            while not queue.empty():
+                command_id = queue.get()
+                logger.info(f"would execute command: {command_id}")
+
+
+def start_backgroup_process():
+    _logger.warning("start_backgroup_process called")
+    global _process
+
+    _process = Process(target=poll_from_usb, args=(_queue,))
+    _process.start()
+    atexit.register(_end_running_process)
diff --git a/backend/runsever.py b/backend/runsever.py
new file mode 100644
index 0000000..a316945
--- /dev/null
+++ b/backend/runsever.py
@@ -0,0 +1,3 @@
+from . import create_app
+
+application = create_app()
diff --git a/requirements.txt b/requirements.txt
index 8d4a90a..98765ef 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
+flask-api>=3.0.post1,<4
 pre-commit
 pyserial>=3.5,<4