tf-iot-consumer/site/app.py

"""
IoT Consumer — Flask app that reads IoT events from Kafka (TLS + SASL)
and stores them in Redis (cache) + MongoDB (permanent).

Env vars (set by Terraform):
  KAFKA_BROKERS     — bootstrap server (host:port)
  KAFKA_TOPIC       — topic name
  KAFKA_USERNAME    — SASL username
  KAFKA_PASSWORD    — SASL password
  KAFKA_CA_CRT      — CA certificate (PEM)
  KAFKA_USER_CRT    — user certificate (PEM)
  KAFKA_USER_KEY    — user private key (PEM)
  KAFKA_GROUP_ID    — consumer group id
  REDIS_HOST        — Redis host
  REDIS_PORT        — Redis port (default 6379)
  REDIS_PASSWORD    — Redis password
  MONGO_URI         — MongoDB connection URI
  MONGO_DB          — MongoDB database name
"""

import json
import os
import tempfile
import threading

from flask import Flask, jsonify
from kafka import KafkaConsumer
import redis
import pymongo

app = Flask(__name__)

# --- Config ---
KAFKA_BROKERS = os.environ["KAFKA_BROKERS"]
KAFKA_TOPIC = os.environ["KAFKA_TOPIC"]
KAFKA_USERNAME = os.environ["KAFKA_USERNAME"]
KAFKA_PASSWORD = os.environ["KAFKA_PASSWORD"]
KAFKA_CA_CRT = os.environ.get("KAFKA_CA_CRT", "")
KAFKA_USER_CRT = os.environ.get("KAFKA_USER_CRT", "")
KAFKA_USER_KEY = os.environ.get("KAFKA_USER_KEY", "")
KAFKA_GROUP_ID = os.environ.get("KAFKA_GROUP_ID", "iot-consumer-group")

REDIS_HOST = os.environ["REDIS_HOST"]
REDIS_PORT = int(os.environ.get("REDIS_PORT", 6379))
REDIS_PASSWORD = os.environ.get("REDIS_PASSWORD", "")

MONGO_URI = os.environ["MONGO_URI"]
MONGO_DB = os.environ.get("MONGO_DB", "iot")

# --- TLS certs → temp files ---
_cert_dir = tempfile.mkdtemp(prefix="kafka-certs-")

def _write_cert(name, content):
    if not content:
        return None
    path = os.path.join(_cert_dir, name)
    with open(path, "w") as f:
        f.write(content)
    return path

_ca_file = _write_cert("ca.crt", KAFKA_CA_CRT)
_cert_file = _write_cert("user.crt", KAFKA_USER_CRT)
_key_file = _write_cert("user.key", KAFKA_USER_KEY)

# --- Clients ---
events_consumed = 0
errors_count = 0
redis_client = None
mongo_client = None
mongo_coll = None


def get_redis():
    global redis_client
    if redis_client is None:
        redis_client = redis.Redis(
            host=REDIS_HOST,
            port=REDIS_PORT,
            password=REDIS_PASSWORD or None,
            decode_responses=True,
        )
        print("[CONSUMER] Redis connected")
    return redis_client


def get_mongo():
    global mongo_client, mongo_coll
    if mongo_client is None:
        mongo_client = pymongo.MongoClient(MONGO_URI)
        db = mongo_client[MONGO_DB]
        mongo_coll = db["iot_events"]
        mongo_coll.create_index("timestamp", expireAfterSeconds=604800)
        print("[CONSUMER] MongoDB connected")
    return mongo_coll


def store_event(event):
    r = get_redis()
    sensor_id = event["sensor_id"]
    value = event["value"]
    unit = event["unit"]
    ts = event["timestamp"]

    # Redis: latest value per sensor
    r.hset("iot:latest", sensor_id, json.dumps({
        "value": value, "unit": unit, "location": event["location"], "timestamp": ts,
    }))

    # Redis: counter per sensor type
    r.hincrby("iot:counters", event["device_type"], 1)

    # Redis: sorted set for recent events (last 1000)
    r.zadd("iot:recent", {json.dumps(event): 0})
    r.zremrangebyrank("iot:recent", 0, -1001)

    # MongoDB: permanent storage
    coll = get_mongo()
    coll.insert_one({
        "event_id": event["event_id"],
        "sensor_id": sensor_id,
        "device_type": event["device_type"],
        "location": event["location"],
        "value": value,
        "unit": unit,
        "timestamp": ts,
    })


def consume_loop():
    global events_consumed, errors_count

    kwargs = {
        "bootstrap_servers": KAFKA_BROKERS,
        "security_protocol": "SASL_SSL",
        "sasl_mechanism": "PLAIN",
        "sasl_plain_username": KAFKA_USERNAME,
        "sasl_plain_password": KAFKA_PASSWORD,
        "group_id": KAFKA_GROUP_ID,
        "auto_offset_reset": "earliest",
        "value_deserializer": lambda m: json.loads(m.decode("utf-8")),
        "max_poll_records": 20,
    }
    if _ca_file:
        kwargs["ssl_cafile"] = _ca_file
    if _cert_file:
        kwargs["ssl_certfile"] = _cert_file
    if _key_file:
        kwargs["ssl_keyfile"] = _key_file
    kwargs["ssl_check_hostname"] = False

    consumer = KafkaConsumer(KAFKA_TOPIC, **kwargs)
    print(f"[CONSUMER] Listening on topic '{KAFKA_TOPIC}'...")

    for message in consumer:
        try:
            store_event(message.value)
            events_consumed += 1
            if events_consumed % 10 == 0:
                print(f"[CONSUMER] Processed {events_consumed} events")
        except Exception as e:
            errors_count += 1
            print(f"[CONSUMER] Error: {e}")


@app.route("/")
def index():
    return jsonify({
        "service": "iot-consumer",
        "status": "running",
        "kafka_topic": KAFKA_TOPIC,
        "events_consumed": events_consumed,
        "errors": errors_count,
    })


@app.route("/health")
def health():
    return jsonify({"status": "ok", "events_consumed": events_consumed})


if __name__ == "__main__":
    threading.Thread(target=consume_loop, daemon=True).start()
    port = int(os.environ.get("PORT", 5000))
    app.run(host="0.0.0.0", port=port)