Merge pull request #75 from sparky8512/protocol-robustness

Robustness against field removal in gRPC protocol

for issue #66

dish_common.py

@@ -318,7 +318,7 @@ def get_history_stats(opts, gstate, add_item, add_sequence, flush_history):
             timestamp = int(time.time())
             history = starlink_grpc.get_history(context=gstate.context)
             gstate.timestamp_stats = timestamp
-        except grpc.RpcError as e:
+        except (AttributeError, ValueError, grpc.RpcError) as e:
             conn_error(opts, "Failure getting history: %s", str(starlink_grpc.GrpcError(e)))
             history = None
 

starlink_grpc.py

@@ -535,6 +535,8 @@ class GrpcError(Exception):
             msg = e.details()
         elif isinstance(e, grpc.RpcError):
             msg = "Unknown communication or service error"
+        elif isinstance(e, (AttributeError, IndexError, TypeError, ValueError)):
+            msg = "Protocol error"
         else:
             msg = str(e)
         super().__init__(msg, *args, **kwargs)
@@ -617,8 +619,11 @@ def status_field_names(context: Optional[ChannelContext] = None):
         except grpc.RpcError as e:
             raise GrpcError(e) from e
     alert_names = []
+    try:
         for field in dish_pb2.DishAlerts.DESCRIPTOR.fields:
             alert_names.append("alert_" + field.name)
+    except AttributeError:
+        pass
 
     return _field_names(StatusDict), _field_names(ObstructionDict), alert_names
 
@@ -646,8 +651,12 @@ def status_field_types(context: Optional[ChannelContext] = None):
             call_with_channel(resolve_imports, context=context)
         except grpc.RpcError as e:
             raise GrpcError(e) from e
-    return (_field_types(StatusDict), _field_types(ObstructionDict),
+    num_alerts = 0
-            [bool] * len(dish_pb2.DishAlerts.DESCRIPTOR.fields))
+    try:
+        num_alerts = len(dish_pb2.DishAlerts.DESCRIPTOR.fields)
+    except AttributeError:
+        pass
+    return (_field_types(StatusDict), _field_types(ObstructionDict), [bool] * num_alerts)
 
 
 def get_status(context: Optional[ChannelContext] = None):
@@ -661,6 +670,9 @@ def get_status(context: Optional[ChannelContext] = None):
 
     Raises:
         grpc.RpcError: Communication or service error.
+        AttributeError, ValueError: Protocol error. Either the target is not a
+            Starlink user terminal or the grpc protocol has changed in a way
+            this module cannot handle.
     """
     def grpc_call(channel):
         if imports_pending:
@@ -689,7 +701,7 @@ def get_id(context: Optional[ChannelContext] = None) -> str:
     try:
         status = get_status(context)
         return status.device_info.id
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         raise GrpcError(e) from e
 
 
@@ -711,62 +723,78 @@ def status_data(
     """
     try:
         status = get_status(context)
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         raise GrpcError(e) from e
 
+    try:
         if status.HasField("outage"):
             if status.outage.cause == dish_pb2.DishOutage.Cause.NO_SCHEDULE:
                 # Special case translate this to equivalent old name
                 state = "SEARCHING"
             else:
+                try:
                     state = dish_pb2.DishOutage.Cause.Name(status.outage.cause)
+                except ValueError:
+                    # Unlikely, but possible if dish is running newer firmware
+                    # than protocol data pulled via reflection
+                    state = str(status.outage.cause)
         else:
             state = "CONNECTED"
+    except (AttributeError, ValueError):
+        state = "UNKNOWN"
 
     # More alerts may be added in future, so in addition to listing them
     # individually, provide a bit field based on field numbers of the
     # DishAlerts message.
     alerts = {}
     alert_bits = 0
+    try:
         for field in status.alerts.DESCRIPTOR.fields:
-        value = getattr(status.alerts, field.name)
+            value = getattr(status.alerts, field.name, False)
             alerts["alert_" + field.name] = value
             if field.number < 65:
                 alert_bits |= (1 if value else 0) << (field.number - 1)
+    except AttributeError:
+        pass
 
-    if (status.obstruction_stats.avg_prolonged_obstruction_duration_s > 0.0
-            and not math.isnan(status.obstruction_stats.avg_prolonged_obstruction_interval_s)):
-        obstruction_duration = status.obstruction_stats.avg_prolonged_obstruction_duration_s
-        obstruction_interval = status.obstruction_stats.avg_prolonged_obstruction_interval_s
-    else:
     obstruction_duration = None
     obstruction_interval = None
+    obstruction_stats = getattr(status, "obstruction_stats", None)
+    if obstruction_stats is not None:
+        try:
+            if (obstruction_stats.avg_prolonged_obstruction_duration_s > 0.0
+                    and not math.isnan(obstruction_stats.avg_prolonged_obstruction_interval_s)):
+                obstruction_duration = obstruction_stats.avg_prolonged_obstruction_duration_s
+                obstruction_interval = obstruction_stats.avg_prolonged_obstruction_interval_s
+        except AttributeError:
+            pass
 
+    device_info = getattr(status, "device_info", None)
     return {
-        "id": status.device_info.id,
+        "id": getattr(device_info, "id", None),
-        "hardware_version": status.device_info.hardware_version,
+        "hardware_version": getattr(device_info, "hardware_version", None),
-        "software_version": status.device_info.software_version,
+        "software_version": getattr(device_info, "software_version", None),
         "state": state,
-        "uptime": status.device_state.uptime_s,
+        "uptime": getattr(getattr(status, "device_state", None), "uptime_s", None),
         "snr": None,  # obsoleted in grpc service
-        "seconds_to_first_nonempty_slot": status.seconds_to_first_nonempty_slot,
+        "seconds_to_first_nonempty_slot": getattr(status, "seconds_to_first_nonempty_slot", None),
-        "pop_ping_drop_rate": status.pop_ping_drop_rate,
+        "pop_ping_drop_rate": getattr(status, "pop_ping_drop_rate", None),
-        "downlink_throughput_bps": status.downlink_throughput_bps,
+        "downlink_throughput_bps": getattr(status, "downlink_throughput_bps", None),
-        "uplink_throughput_bps": status.uplink_throughput_bps,
+        "uplink_throughput_bps": getattr(status, "uplink_throughput_bps", None),
-        "pop_ping_latency_ms": status.pop_ping_latency_ms,
+        "pop_ping_latency_ms": getattr(status, "pop_ping_latency_ms", None),
         "alerts": alert_bits,
-        "fraction_obstructed": status.obstruction_stats.fraction_obstructed,
+        "fraction_obstructed": getattr(obstruction_stats, "fraction_obstructed", None),
-        "currently_obstructed": status.obstruction_stats.currently_obstructed,
+        "currently_obstructed": getattr(obstruction_stats, "currently_obstructed", None),
         "seconds_obstructed": None,  # obsoleted in grpc service
         "obstruction_duration": obstruction_duration,
         "obstruction_interval": obstruction_interval,
-        "direction_azimuth": status.boresight_azimuth_deg,
+        "direction_azimuth": getattr(status, "boresight_azimuth_deg", None),
-        "direction_elevation": status.boresight_elevation_deg,
+        "direction_elevation": getattr(status, "boresight_elevation_deg", None),
-        "is_snr_above_noise_floor": status.is_snr_above_noise_floor,
+        "is_snr_above_noise_floor": getattr(status, "is_snr_above_noise_floor", None),
     }, {
         "wedges_fraction_obstructed[]": [None] * 12,  # obsoleted in grpc service
         "raw_wedges_fraction_obstructed[]": [None] * 12,  # obsoleted in grpc service
-        "valid_s": status.obstruction_stats.valid_s,
+        "valid_s": getattr(obstruction_stats, "valid_s", None),
     }, alerts
 
 
@@ -801,6 +829,9 @@ def get_location(context: Optional[ChannelContext] = None):
 
     Raises:
         grpc.RpcError: Communication or service error.
+        AttributeError, ValueError: Protocol error. Either the target is not a
+            Starlink user terminal or the grpc protocol has changed in a way
+            this module cannot handle.
     """
     def grpc_call(channel):
         if imports_pending:
@@ -829,7 +860,7 @@ def location_data(context: Optional[ChannelContext] = None) -> LocationDict:
     """
     try:
         location = get_location(context)
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         if isinstance(e, grpc.Call) and e.code() is grpc.StatusCode.PERMISSION_DENIED:
             return {
                 "latitude": None,
@@ -838,11 +869,17 @@ def location_data(context: Optional[ChannelContext] = None) -> LocationDict:
             }
         raise GrpcError(e) from e
 
+    try:
         return {
             "latitude": location.lla.lat,
             "longitude": location.lla.lon,
-        "altitude": location.lla.alt,
+            "altitude": getattr(location.lla, "alt", None),
         }
+    except AttributeError as e:
+        # Allow None for altitude, but since all None values has special
+        # meaning for this function, any other protocol change is flagged as
+        # an error.
+        raise GrpcError(e) from e
 
 
 def history_bulk_field_names():
@@ -927,6 +964,9 @@ def get_history(context: Optional[ChannelContext] = None):
 
     Raises:
         grpc.RpcError: Communication or service error.
+        AttributeError, ValueError: Protocol error. Either the target is not a
+            Starlink user terminal or the grpc protocol has changed in a way
+            this module cannot handle.
     """
     def grpc_call(channel: grpc.Channel):
         if imports_pending:
@@ -942,8 +982,12 @@ def _compute_sample_range(history,
                           parse_samples: int,
                           start: Optional[int] = None,
                           verbose: bool = False):
+    try:
         current = int(history.current)
         samples = len(history.pop_ping_drop_rate)
+    except (AttributeError, TypeError):
+        # Without current and pop_ping_drop_rate, history is unusable.
+        return range(0), 0, None
 
     if verbose:
         print("current counter:       " + str(current))
@@ -1018,8 +1062,14 @@ def concatenate_history(history1,
         An object with the unwrapped history data and the same attribute
         fields as a grpc history object.
     """
+    try:
         size2 = len(history2.pop_ping_drop_rate)
         new_samples = history2.current - history1.current
+    except (AttributeError, TypeError):
+        # Something is wrong. Probably both history objects are bad, so no
+        # point in trying to combine them.
+        return history1
+
     if new_samples < 0:
         if verbose:
             print("Dish reboot detected. Appending anyway.")
@@ -1034,6 +1084,7 @@ def concatenate_history(history1,
 
     unwrapped = UnwrappedHistory()
     for field in HISTORY_FIELDS:
+        if hasattr(history1, field) and hasattr(history2, field):
             setattr(unwrapped, field, [])
     unwrapped.unwrapped = True
 
@@ -1041,12 +1092,20 @@ def concatenate_history(history1,
         history1, samples1, start=start1)
     for i in sample_range:
         for field in HISTORY_FIELDS:
+            if hasattr(unwrapped, field):
+                try:
                     getattr(unwrapped, field).append(getattr(history1, field)[i])
+                except (IndexError, TypeError):
+                    pass
 
     sample_range, ignore1, ignore2 = _compute_sample_range(history2, new_samples)  # pylint: disable=unused-variable
     for i in sample_range:
         for field in HISTORY_FIELDS:
+            if hasattr(unwrapped, field):
+                try:
                     getattr(unwrapped, field).append(getattr(history2, field)[i])
+                except (IndexError, TypeError):
+                    pass
 
     unwrapped.current = history2.current
     return unwrapped
@@ -1096,7 +1155,7 @@ def history_bulk_data(parse_samples: int,
     if history is None:
         try:
             history = get_history(context)
-        except grpc.RpcError as e:
+        except (AttributeError, ValueError, grpc.RpcError) as e:
             raise GrpcError(e) from e
 
     sample_range, parsed_samples, current = _compute_sample_range(history,
@@ -1110,11 +1169,30 @@ def history_bulk_data(parse_samples: int,
     uplink_throughput_bps = []
 
     for i in sample_range:
+        # pop_ping_drop_rate is checked in _compute_sample_range
         pop_ping_drop_rate.append(history.pop_ping_drop_rate[i])
-        pop_ping_latency_ms.append(
+
-            history.pop_ping_latency_ms[i] if history.pop_ping_drop_rate[i] < 1 else None)
+        latency = None
-        downlink_throughput_bps.append(history.downlink_throughput_bps[i])
+        try:
-        uplink_throughput_bps.append(history.uplink_throughput_bps[i])
+            if history.pop_ping_drop_rate[i] < 1:
+                latency = history.pop_ping_latency_ms[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
+        pop_ping_latency_ms.append(latency)
+
+        downlink = None
+        try:
+            downlink = history.downlink_throughput_bps[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
+        downlink_throughput_bps.append(downlink)
+
+        uplink = None
+        try:
+            uplink = history.uplink_throughput_bps[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
+        uplink_throughput_bps.append(uplink)
 
     return {
         "samples": parsed_samples,
@@ -1181,7 +1259,7 @@ def history_stats(
     if history is None:
         try:
             history = get_history(context)
-        except grpc.RpcError as e:
+        except (AttributeError, ValueError, grpc.RpcError) as e:
             raise GrpcError(e) from e
 
     sample_range, parsed_samples, current = _compute_sample_range(history,
@@ -1230,12 +1308,25 @@ def history_stats(
             init_run_length = 0
         tot += d
 
+        down = 0.0
+        try:
             down = history.downlink_throughput_bps[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
         usage_down += down
+
+        up = 0.0
+        try:
             up = history.uplink_throughput_bps[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
         usage_up += up
 
+        rtt = 0.0
+        try:
             rtt = history.pop_ping_latency_ms[i]
+        except (AttributeError, IndexError, TypeError):
+            pass
         # note that "full" here means the opposite of ping drop full
         if d == 0.0:
             rtt_full.append(rtt)
@@ -1342,6 +1433,9 @@ def get_obstruction_map(context: Optional[ChannelContext] = None):
 
     Raises:
         grpc.RpcError: Communication or service error.
+        AttributeError, ValueError: Protocol error. Either the target is not a
+            Starlink user terminal or the grpc protocol has changed in a way
+            this module cannot handle.
     """
     def grpc_call(channel: grpc.Channel):
         if imports_pending:
@@ -1368,15 +1462,19 @@ def obstruction_map(context: Optional[ChannelContext] = None):
         representation the SNR data instead, see `get_obstruction_map`.
 
     Raises:
-        GrpcError: Failed getting status info from the Starlink user terminal.
+        GrpcError: Failed getting obstruction data from the Starlink user
+            terminal.
     """
     try:
         map_data = get_obstruction_map(context)
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         raise GrpcError(e) from e
 
+    try:
         cols = map_data.num_cols
         return tuple((map_data.snr[i:i + cols]) for i in range(0, cols * map_data.num_rows, cols))
+    except (AttributeError, IndexError, TypeError) as e:
+        raise GrpcError(e) from e
 
 
 def reboot(context: Optional[ChannelContext] = None) -> None:
@@ -1400,7 +1498,7 @@ def reboot(context: Optional[ChannelContext] = None) -> None:
 
     try:
         call_with_channel(grpc_call, context=context)
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         raise GrpcError(e) from e
 
 
@@ -1427,5 +1525,5 @@ def set_stow_state(unstow: bool = False, context: Optional[ChannelContext] = Non
 
     try:
         call_with_channel(grpc_call, context=context)
-    except grpc.RpcError as e:
+    except (AttributeError, ValueError, grpc.RpcError) as e:
         raise GrpcError(e) from e