docs(Redis Workers): Reimplementation

Reimplementing redis server worker management using the multiprocessing
library. Not tested and not final.

apps/__init__.py

@@ -1,3 +1,4 @@
+import os.path
 import platform
 import subprocess
 from datetime import datetime
@@ -79,11 +80,17 @@ def initialize_settings():
         # Start redis workers on Linux only
         if platform.system() == "Linux":
             from apps.alpr.models.settings import CameraSettings
-            camera_workers = len(CameraSettings.get_all_enabled())
-            workers_cmd = subprocess.run(["./workers.py", "-c", camera_workers, "-g", camera_workers])
-            print("workers_cmd.returncode = {}".format(workers_cmd.returncode))
-            print("workers_cmd.stdout = {}".format(workers_cmd.stdout))
-            print("workers_cmd.stderr = {}".format(workers_cmd.stderr))
+            camera_workers = CameraSettings.get_all_enabled_count()
+            workers_cmd = subprocess.Popen(["python3", os.path.dirname(os.path.realpath(__file__)) +
+                                            "/workers.py", "-c", str(camera_workers), "-g", str(camera_workers)],
+                                           stderr=subprocess.PIPE, stdout=subprocess.PIPE)
+            output, error = workers_cmd.communicate()
+            if workers_cmd.returncode != 0:
+                app.logger.info("workers_cmd.returncode = {}".format(workers_cmd.returncode))
+                app.logger.info("workers_cmd.errorcode = {}".format(str(error, 'utf-8')))
+
+            app.logger.info("workers_cmd.stdout = {}".format(workers_cmd.stdout))
+            app.logger.info("workers_cmd.stderr = {}".format(workers_cmd.stderr))
 
 
 def create_app(config) -> Flask:

apps/alpr/enums.py

@@ -6,6 +6,11 @@ class AccountStatus(enum.Enum):
     ACTIVATED = 1
 
 
+class AccountVerified(enum.Enum):
+    NON_VERIFIED = 0
+    VERIFIED = 1
+
+
 class ChartType(enum.Enum):
     ALERT_CHART = "alert-chart"
     PLATES_CAPTURED_CHART = "plates-captured-chart"
@@ -18,16 +23,17 @@ class DataType(enum.Enum):
     VEHICLE = "vehicle"
 
 
+class MultiProcessCommand(enum.Enum):
+    START_WORKER = "start-worker"
+    STOP_WORKER = "stop-worker"
+    CLOSE_CONNECTION = "close"
+
+
 class UserRole(enum.Enum):
     ADMIN = "ADMIN"
     REGULAR = "NONADMIN"
 
 
-class AccountVerified(enum.Enum):
-    NON_VERIFIED = 0
-    VERIFIED = 1
-
-
 class WorkerType(enum.Enum):
     # worker type = queue name
     Camera = 'cameras'

apps/alpr/models/settings.py

@@ -101,6 +101,10 @@ def filter_by_id(cls, _id: int) -> "CameraSettings":
     def get_all_enabled(cls) -> []:
         return cls.query.filter_by(enable=True)
 
+    @classmethod
+    def get_all_enabled_count(cls) -> int:
+        return cls.query.filter_by(enable=True).count()
+
     @classmethod
     def get_camera_label(cls, _camera_id: int) -> "CameraSettings":
         camera = cls.query.filter_by(camera_id=_camera_id).first()