Expose some timeseries from TimescaleDB over Django

monitoring/README.md

@@ -0,0 +1,129 @@
+# Asset telemetry monitoring
+
+[!CAUTION]
+This is a PoC, not suitable for real world due to lack of any authentication and security
+
+## Pre-requisites
+
+- Python 3.12
+- Podman (or Docker)
+
+## Architecture
+
+The `dispatcher.py` script collects data (`cab` commands) from a CommandStation and sends it a MQTT broker. 
+
+The command being monitored is the `<l cab reg speedByte functMap>` one returned by the `<t cab speed dir>` throttle command. See the [DCC-EX command reference](https://dcc-ex.com/reference/software/command-summary-consolidated.html#t-cab-speed-dir-set-cab-loco-speed).
+
+`mosquitto` is the MQTT broker.
+
+The `handler.py` script subscribes to the MQTT broker and saves relevant data to the Timescale database.
+
+Data is finally save into a Timescale hypertable.
+
+## How to run
+
+### Deploy Timescale
+
+```bash
+$ podman run -d -p 5432:5432 -v $(pwd)/data:/var/lib/postgresql/data -e "POSTGRES_USER=dccmonitor" -e "POSTGRES_PASSWORD=dccmonitor" --name timescale timescale/timescaledb:latest-pg17
+```
+[!IMPORTANT]
+A volume should be created for persistent data
+
+Tables and hypertables are automatically created by the `handler.py` script
+
+### Deploy Mosquitto
+
+```bash
+$ podman run --userns=keep-id -d -p 1883:1883 -v $(pwd)/config/mosquitto.conf:/mosquitto/config/mosquitto.conf --name mosquitto eclipse-mosquitto:2.0
+```
+
+### Run the dispatcher and the handler
+
+```bash
+$ python dispatcher.py
+```
+
+```bash
+$ python handler.py
+```
+
+## Debug data in Timescale
+
+### Create a 10 secs aggregated data table
+
+```sql
+CREATE MATERIALIZED VIEW telemetry_10secs
+WITH (timescaledb.continuous) AS
+SELECT 
+    time_bucket('10 seconds', timestamp) AS bucket,
+    cab,
+    ROUND(CAST(AVG(speed) AS NUMERIC), 1) AS avg_speed,
+    MIN(speed) AS min_speed,
+    MAX(speed) AS max_speed
+FROM telemetry
+GROUP BY bucket, cab;
+```
+
+and set the update policy:
+
+```sql
+SELECT add_continuous_aggregate_policy(
+    'telemetry_10secs',
+    start_offset => INTERVAL '1 hour',  -- Go back 1 hour for updates
+    end_offset   => INTERVAL '1 minute', -- Keep the latest 5 min fresh
+    schedule_interval => INTERVAL '1 minute' -- Run every minute
+);
+
+```
+
+### Running statistics from 10 seconds table
+
+```sql
+WITH speed_durations AS (
+    SELECT 
+        cab,
+        avg_speed,
+        max_speed,
+        bucket AS start_time,
+        LEAD(bucket) OVER (
+            PARTITION BY cab ORDER BY bucket
+        ) AS end_time,
+        LEAD(bucket) OVER (PARTITION BY cab ORDER BY bucket) - bucket AS duration
+    FROM telemetry_10secs
+)
+SELECT * FROM speed_durations WHERE end_time IS NOT NULL;
+```
+
+and filtered by `cab` number, via a function
+
+```sql
+CREATE FUNCTION get_speed_durations(cab_id INT) 
+RETURNS TABLE (
+    cab INT, 
+    speed DOUBLE PRECISION, 
+    dir TEXT, 
+    start_time TIMESTAMPTZ, 
+    end_time TIMESTAMPTZ, 
+    duration INTERVAL
+) 
+AS $$
+WITH speed_durations AS (
+    SELECT 
+        cab,
+        avg_speed,
+        max_speed,
+        bucket AS start_time,
+        LEAD(bucket) OVER (
+            PARTITION BY cab ORDER BY bucket
+        ) AS end_time,
+        LEAD(bucket) OVER (PARTITION BY cab ORDER BY bucket) - bucket AS duration
+    FROM telemetry_10secs
+)
+SELECT * FROM speed_durations WHERE end_time IS NOT NULL AND cab = cab_id;
+$$ LANGUAGE sql;
+
+-- Refresh data
+CALL refresh_continuous_aggregate('telemetry_10secs', NULL, NULL);
+SELECT * FROM get_speed_durations(1);
+```

monitoring/compose.yml

@@ -0,0 +1,36 @@
+# -*- coding: utf-8 -*-
+# vim: tabstop=2 shiftwidth=2 softtabstop=2
+networks:
+  net:
+
+volumes:
+  pgdata:
+  staticdata:
+
+x-op-service-default: &service_default
+  restart: always  # unless-stopped
+  init: true
+
+services:
+  timescale:
+    <<: *service_default
+    image: timescale/timescaledb:latest-pg17
+    ports:
+        - "${CUSTOM_DOCKER_IP:-0.0.0.0}:5432:5432"
+    environment:
+      POSTGRES_USER: "dccmonitor"
+      POSTGRES_PASSWORD: "dccmonitor"
+    volumes:
+      - "pgdata:/var/lib/postgresql/data"
+    networks:
+      - net
+
+  broker:
+    <<: *service_default
+    image: eclipse-mosquitto:2.0
+    ports:
+        - "${CUSTOM_DOCKER_IP:-0.0.0.0}:1883:1883"
+    volumes:
+      - "./config/mosquitto.conf:/mosquitto/config/mosquitto.conf:ro"
+    networks:
+      - net

monitoring/config/mosquitto.conf

@@ -0,0 +1,2 @@
+allow_anonymous true
+listener 1883

monitoring/dispatcher.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+
+import os
+import time
+import json
+import socket
+import logging
+import paho.mqtt.client as mqtt
+
+# FIXME: create a configuration
+# TCP Socket Configuration
+TCP_HOST = "192.168.10.110"  # Replace with your TCP server IP
+TCP_PORT = 2560              # Replace with your TCP server port
+
+# FIXME: create a configuration
+# MQTT Broker Configuration
+MQTT_BROKER = "localhost"
+MQTT_PORT = 1883
+MQTT_TOPIC = "telemetry/commandstation"
+
+# Connect to MQTT Broker
+mqtt_client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2)
+
+
+# Connect function with automatic reconnection
+def connect_mqtt():
+    while True:
+        try:
+            mqtt_client.connect(MQTT_BROKER, MQTT_PORT, keepalive=60)
+            mqtt_client.loop_start()  # Start background loop
+            logging.info("Connected to MQTT broker!")
+            return
+        except Exception as e:
+            logging.info(f"Connection failed: {e}. Retrying in 5 seconds...")
+            time.sleep(5)  # Wait before Retrying
+
+
+# Ensure connection before publishing
+def safe_publish(topic, message):
+    if not mqtt_client.is_connected():
+        print("MQTT Disconnected! Reconnecting...")
+        connect_mqtt()  # Reconnect if disconnected
+
+    result = mqtt_client.publish(topic, message, qos=1)
+    result.wait_for_publish()  # Ensure message is published
+    logging.debug(f"Published: {message}")
+
+
+def process_message(message):
+    """Parses the '<l cab speed dir>' format and converts it to JSON."""
+    if not message.startswith("<l"):
+        return None
+
+    parts = message.strip().split()  # Split by spaces
+    if len(parts) != 5:
+        logging.debug(f"Invalid speed command: {message}")
+        return None
+
+    _, _cab, _, _speed, _ = parts  # Ignore the first `<t`
+    cab = int(_cab)
+    speed = int(_speed)
+    if speed > 1 and speed < 128:
+        direction = "r"
+        speed = speed - 1
+    elif speed > 129 and speed < 256:
+        direction = "f"
+        speed = speed - 129
+    else:
+        speed = 0
+        direction = "n"
+
+    try:
+        json_data = {
+            "cab": cab,
+            "speed": speed,
+            "dir": direction
+        }
+        return json_data
+    except ValueError as e:
+        logging.error(f"Error parsing message: {e}")
+        return None
+
+
+def start_tcp_listener():
+    """Listens for incoming TCP messages and publishes them to MQTT."""
+    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+        sock.connect((TCP_HOST, TCP_PORT))
+        logging.info(
+            f"Connected to TCP server at {TCP_HOST}:{TCP_PORT}"
+        )
+
+        while True:
+            data = sock.recv(1024).decode("utf-8")  # Read a chunk of data
+            if not data:
+                break
+
+            lines = data.strip().split("\n")  # Handle multiple lines
+            for line in lines:
+                json_data = process_message(line)
+                if json_data:
+                    safe_publish(MQTT_TOPIC, json.dumps(json_data))
+
+
+# Start the listener
+if __name__ == "__main__":
+    logging.basicConfig(level=os.getenv("DCC_LOGLEVEL", "INFO").upper())
+    start_tcp_listener()

monitoring/handler.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+
+import os
+import json
+import logging
+import datetime
+import psycopg2
+import paho.mqtt.client as mqtt
+
+# MQTT Broker Configuration
+MQTT_BROKER = "localhost"
+MQTT_PORT = 1883
+MQTT_TOPIC = "telemetry/commandstation"
+
+# TimescaleDB Configuration
+DB_HOST = "localhost"
+DB_NAME = "dccmonitor"
+DB_USER = "dccmonitor"
+DB_PASSWORD = "dccmonitor"
+
+
+# The callback for when the client receives a CONNACK response from the server.
+def on_connect(client, userdata, flags, reason_code, properties):
+    logging.info(f"Connected with result code {reason_code}")
+    # Subscribing in on_connect() means that if we lose the connection and
+    # reconnect then subscriptions will be renewed.
+    client.subscribe(MQTT_TOPIC)
+
+
+# MQTT Callback: When a new message arrives
+def on_message(client, userdata, msg):
+    try:
+        payload = json.loads(msg.payload.decode("utf-8"))
+        cab = payload["cab"]
+        speed = payload["speed"]
+        direction = payload["dir"]
+        timestamp = datetime.datetime.now(datetime.UTC)
+
+        # Insert into TimescaleDB
+        cur.execute(
+            "INSERT INTO telemetry (timestamp, cab, speed, dir) VALUES (%s, %s, %s, %s)",  # noqa: E501
+            (timestamp, cab, speed, direction),
+        )
+        conn.commit()
+        logging.debug(
+            f"Inserted: {timestamp} | Cab: {cab} | Speed: {speed} | Dir: {direction}"  # noqa: E501
+        )
+
+    except Exception as e:
+        logging.error(f"Error processing message: {e}")
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=os.getenv("DCC_LOGLEVEL", "INFO").upper())
+
+    # Connect to TimescaleDB
+    conn = psycopg2.connect(
+        dbname=DB_NAME, user=DB_USER, password=DB_PASSWORD, host=DB_HOST
+    )
+    cur = conn.cursor()
+
+    # Ensure hypertable exists
+    cur.execute("""
+        CREATE TABLE IF NOT EXISTS telemetry (
+            timestamp TIMESTAMPTZ NOT NULL DEFAULT now(),
+            cab INT NOT NULL,
+            speed DOUBLE PRECISION NOT NULL,
+            dir TEXT NOT NULL
+        );
+    """)
+    conn.commit()
+
+    # Convert table to hypertable if not already
+    cur.execute("SELECT EXISTS (SELECT 1 FROM timescaledb_information.hypertables WHERE hypertable_name = 'telemetry');")  # noqa: E501
+    if not cur.fetchone()[0]:
+        cur.execute("SELECT create_hypertable('telemetry', 'timestamp');")
+        conn.commit()
+
+    # Setup MQTT Client
+    client = mqtt.Client(mqtt.CallbackAPIVersion.VERSION2)
+    client.on_connect = on_connect
+    client.on_message = on_message
+    client.connect(MQTT_BROKER, MQTT_PORT)
+
+    # Start listening for messages
+    logging.info(f"Listening for MQTT messages on {MQTT_TOPIC}...")
+    client.loop_forever()

monitoring/requirements.txt

@@ -0,0 +1,2 @@
+paho-mqtt
+psycopg2-binary

ram/ram/db_router.py

@@ -0,0 +1,32 @@
+class TelemetryRouter:
+    db_table = "telemetry_10secs"
+
+    def db_for_read(self, model, **hints):
+        """Send read operations to the correct database."""
+        if model._meta.db_table == self.db_table:
+            return "telemetry"  # Replace with your database name
+        return None  # Default database
+
+    def db_for_write(self, model, **hints):
+        """Send write operations to the correct database."""
+        if model._meta.db_table == self.db_table:
+            return False  # Prevent Django from writing RO tables
+        return None
+
+    def allow_relation(self, obj1, obj2, **hints):
+        """
+        Allow relations if a model in the auth or contenttypes apps is
+        involved.
+        """
+        if (
+            obj1._meta.db_table == self.db_table
+            or obj2._meta.db_table == self.db_table
+        ):
+            return True
+        return None
+
+    def allow_migrate(self, db, app_label, model_name=None, **hints):
+        """Prevent Django from migrating this model if it's using a specific database."""
+        if db == "telemetry":
+            return False  # Prevent Django from creating/modifying tables
+        return None

ram/ram/settings.py

@@ -95,8 +95,16 @@ DATABASES = {
     "default": {
         "ENGINE": "django.db.backends.sqlite3",
         "NAME": STORAGE_DIR / "db.sqlite3",
-    }
+    },
+    "telemetry": {
+        "ENGINE": "django.db.backends.postgresql",
+        "HOST": "127.0.0.1",
+        "NAME": "dccmonitor",
+        "USER": "dccmonitor",
+        "PASSWORD": "dccmonitor",
+    },
 }
+DATABASE_ROUTERS = ["ram.db_router.TelemetryRouter"]
 
 
 # Password validation

ram/roster/admin.py

@@ -17,6 +17,7 @@ from roster.models import (
     RollingStockImage,
     RollingStockProperty,
     RollingStockJournal,
+    RollingStockTelemetry,
 )
 
 
@@ -287,3 +288,29 @@ class RollingStockAdmin(SortableAdminBase, admin.ModelAdmin):
 
     download_csv.short_description = "Download selected items as CSV"
     actions = [publish, unpublish, download_csv]
+
+
+@admin.register(RollingStockTelemetry)
+class RollingTelemtryAdmin(admin.ModelAdmin):
+    list_filter = ("bucket", "cab")
+    list_display = ("bucket_highres", "cab", "max_speed", "avg_speed")
+
+    def bucket_highres(self, obj):
+        return obj.bucket.strftime("%Y-%m-%d %H:%M:%S")
+
+    bucket_highres.admin_order_field = "bucket"  # Enable sorting
+    bucket_highres.short_description = "Bucket"  # Column name in admin
+
+    def get_changelist_instance(self, request):
+        changelist = super().get_changelist_instance(request)
+        changelist.list_display_links = None  # Disable links
+        return changelist
+
+    def has_add_permission(self, request):
+        return False  # Disable adding new objects
+
+    def has_change_permission(self, request, obj=None):
+        return False  # Disable editing objects
+
+    def has_delete_permission(self, request, obj=None):
+        return False  # Disable deleting objects

ram/roster/models.py

@@ -224,6 +224,20 @@ class RollingStockJournal(models.Model):
     objects = PublicManager()
 
 
+# trick: this is technically an abstract class
+# it is made readonly via db_router and admin to avoid any unwanted change
+class RollingStockTelemetry(models.Model):
+    bucket = models.DateTimeField(primary_key=True, editable=False)
+    cab = models.PositiveIntegerField(editable=False)
+    avg_speed = models.FloatField(editable=False)
+    max_speed = models.PositiveIntegerField(editable=False)
+
+    class Meta:
+        db_table = "telemetry_10secs"
+        ordering = ["cab", "bucket"]
+        verbose_name_plural = "Telemetries"
+
+
 # @receiver(models.signals.post_delete, sender=Cab)
 # def post_save_image(sender, instance, *args, **kwargs):
 #     try:

requirements.txt

@@ -8,7 +8,7 @@ django-countries
 django-health-check
 django-admin-sortable2
 django-tinymce
-# Optional: # psycopg2-binary
+psycopg2-binary
 # Required by django-countries and not always installed
 # by default on modern venvs (like Python 3.12 on Fedora 39)
 setuptools