Message process retry after unexpected message arrival (#13)

* raised errors to prevent ongoing of the match sequence and hanlded ir properly in the upper layers

* bumped the atten results timeout to 1150 ms as Alfen board takes more time now to forward the frames as they have the traffic encripted

* added TimeoutError to the error handling

* fix install-local

* fixed handling error setting the nmid and nmk

* refactored the code and tests to remain in the same states until the correct frame is received or a timeour is raised

* reformated code

* moved the homeplug frame check before the parsing of the bytes to the class

Makefile

@@ -76,7 +76,7 @@ poetry-update: poetry-config
 	poetry update
 
 install-local: .check-env-vars
-	pip install . --extra-index-url https://$PYPI_USER:$PYPI_PASS@pypi.switch-ev.com/simple
+	pip install . --extra-index-url https://${PYPI_USER}:${PYPI_PASS}@pypi.switch-ev.com/simple
 
 run-local:
 	python slac/main.py

pyproject.toml

@@ -6,17 +6,17 @@ authors = ["André Duarte <andre@switch-ev.com, andre14x@gmail.com>"]
 
 [tool.poetry.dependencies]
 python = "^3.9"
-environs = "^9.3.5"
+environs = "^9.5.0"
 mqtt-api = { version = "^0.18.1", source = "pypi-switch"}
 
 [tool.poetry.dev-dependencies]
-pytest = "^6.2.5"
+pytest = "^7.1.1"
 pytest-lazy-fixture = "^0.6.3"
 pytest-cov = "^3.0.0"
 pytest-pylint = "^0.18.0"
 pytest-watch = "^4.2.0"
-pytest-asyncio = "^0.16.0"
-black = "21.11b1"
+pytest-asyncio = "^0.18.3"
+black = "22.3.0"
 isort = "^5.10.1"
 flake8 = "^4.0.1"
 

slac/enums.py

@@ -101,7 +101,7 @@ class Timers(float, Enum):
 # Timers.SLAC_ATTEN_TIMEOUT is the only value in the Timers class that its use
 # is supposed to be done as an integer (type int)
 SLAC_ATTEN_TIMEOUT = 6  # [TT_EVSE_match_MNBC = 600 ms]
-ATTEN_RESULTS_TIMEOUT = 9  # in ms
+ATTEN_RESULTS_TIMEOUT = 1150  # in ms
 
 
 class FramesSizes(int, Enum):

slac/main.py

@@ -28,6 +28,12 @@
 
 @dataclass
 class SlacStatusPayload:
+    """
+    Dataclass to hold the SlacStatus Payload info
+    This class is here as it was missing from mqtt_api by the time this code
+    was implemented.
+    """
+
     evse_id: str
     status: SlacStatus
 
@@ -82,29 +88,44 @@ async def get_cs_parameters(self):
                     "network_interface": "eth0",
                     "connectors": [...],
 
-        If no answer is provided in 60s, a timeout occurs and the slac application stops
+        If no answer is provided in 60s, a timeout occurs and the slac application
+        stops. If the Initialization of the Slac session based on the CS Parameters
+        received fails, the system restarts awaiting for the parameters after 5 secs.
 
         Note:
             The evse_id provided must be unique and is assumed to be associated to
             one and one only network_interface. This is important, as the 'evse_id' is
             used in subsequent messages as an identifier of the running session.
         """
-        cs_parameters: response.CsParametersPayload = await self.request(
-            topic=Topics.JOSEV_CS, payload=request.CsParametersPayload()
-        )
+        while not self.running_sessions:
+            cs_parameters: response.CsParametersPayload = await self.request(
+                topic=Topics.JOSEV_CS, payload=request.CsParametersPayload()
+            )
 
-        if cs_parameters.number_of_evses < 1 or (
-            len(cs_parameters.parameters) != cs_parameters.number_of_evses
-        ):
-            raise AttributeError("Number of evses provided is invalid.")
+            if cs_parameters.number_of_evses < 1 or (
+                len(cs_parameters.parameters) != cs_parameters.number_of_evses
+            ):
+                raise AttributeError("Number of evses provided is invalid.")
 
-        for evse_params in cs_parameters.parameters:
-            # Initialize the Slac Session
-            slac_session = SlacEvseSession(
-                evse_params.evse_id, evse_params.network_interface, self.config
-            )
-            await slac_session.evse_set_key()
-            self.running_sessions.append(slac_session)
+            for evse_params in cs_parameters.parameters:
+                # Initialize the Slac Session
+                try:
+                    slac_session = SlacEvseSession(
+                        evse_params.evse_id, evse_params.network_interface, self.config
+                    )
+                    await slac_session.evse_set_key()
+                    self.running_sessions.append(slac_session)
+                except (OSError, TimeoutError, ValueError) as e:
+                    logger.error(
+                        f"PLC chip initialization failed for "
+                        f"EVSE {evse_params.evse_id}, interface "
+                        f"{evse_params.network_interface}: {e}. \n"
+                        f"Please check your CS parameters. The CS Parameters"
+                        f"request will be resent in 5 secs"
+                    )
+                    self.running_sessions.clear()
+                    await asyncio.sleep(5)
+                    break
 
     @get_session
     @on(MessageName.CP_STATUS)
@@ -146,7 +167,7 @@ async def matching_process(
         self, slac_session: "SlacEvseSession", number_of_retries=3
     ) -> None:
         """
-        Task that is spawned once a state change is detected from A. E or F to
+        Task that is spawned once a state change is detected from A, E or F to
         B, C or D. This task is responsible to run the right methods defined in
         session.py, which as a whole comprise the SLAC protocol.
         In case SLAC fails, it retries up to 3 times to get a match, and
@@ -169,7 +190,15 @@ async def matching_process(
                         slac_session.evse_id, SlacStatus.MATCHING
                     ),
                 )
-                await slac_session.atten_charac_routine()
+                try:
+                    await slac_session.atten_charac_routine()
+                except Exception as e:
+                    slac_session.state = STATE_UNMATCHED
+                    logger.debug(
+                        f"Exception Occurred during Attenuation Charc Routine:"
+                        f"{e} \n"
+                        f"Number of retries left {number_of_retries}"
+                    )
             if slac_session.state == STATE_MATCHED:
                 logger.debug("PEV-EVSE MATCHED Successfully, Link Established")
                 while True: