Troubleshooting Network Connectivity Issue with Dockerized Python Script and Dockerized InfluxDB on a Separate Machine

I’m encountering an issue with a Dockerized Python script on my machine, which is failing to connect to a Dockerized InfluxDB instance running on another machine in my local network. The script worked fine before Dockerization, successfully connecting to and writing data in the remote Dockerized InfluxDB. However, after Dockerizing it, the script can no longer write data to InfluxDB.

Python Script (rabbitmq_to_influxdb.py):

import os
import pika
from influxdb_client import InfluxDBClient, Point, WritePrecision
from influxdb_client.client.write_api import SYNCHRONOUS
import json
import time
import pytz
from datetime import datetime

# Environment variables for service hosts with defaults for local development
rabbitmq_host = os.getenv('RABBITMQ_HOST', 'rabbitmq')

# InfluxDB connection details
influxdb_host = os.getenv('INFLUXDB_HOST', 'OTHER_INFLUX_IP')
token = os.getenv('INFLUXDB_TOKEN', 'OTHER_INFLUX_TOKEN')
org = os.getenv('INFLUXDB_ORG', 'OTHER_INFLUX_ORG')
bucket = os.getenv('INFLUXDB_BUCKET', 'OTHER_INFLUX_BUCKET')


# Initialize InfluxDB client
client = InfluxDBClient(url=influxdb_host, token=token, org=org)
write_api = client.write_api(write_options=SYNCHRONOUS)

# Counter for successful writes
successful_writes = 0

# Connect to RabbitMQ
def connect_to_rabbitmq():
    while True:
        try:
            connection = pika.BlockingConnection(pika.ConnectionParameters(rabbitmq_host))
            channel = connection.channel()
            # Declare the queue here to ensure it exists
            channel.queue_declare(queue='sensor_info', durable=True)
            return connection, channel
        except pika.exceptions.AMQPConnectionError:
            print("Connection to RabbitMQ failed. Retrying...")
            time.sleep(5)  # Wait 5 seconds before retrying

# Callback function to process incoming messages
def callback(ch, method, properties, body):
    global successful_writes  
    data = json.loads(body)
    print(f"Received message: {data}")

    # Convert the timestamp to a format that InfluxDB understands (RFC3339)
    timestamp = datetime.strptime(data['timestamp'], "%Y-%m-%d %H:%M:%S")
    timestamp = timestamp.replace(tzinfo=pytz.UTC)  # Set timezone to UTC

    # Constructing the point to write to InfluxDB
    point = Point("sensor_info").tag("sensor", f"antenna_{data['antenna_id']}")
    
    for key in ['temperature', 'humidity', 'wind_speed']:
        point = point.field(key, float(data[key]))

    point = point.field("gps_latitude", float(data['gps']['latitude']))
    point = point.field("gps_longitude", float(data['gps']['longitude']))
    point = point.field("inclinometer_x", float(data['inclinometer']['x']))
    point = point.field("inclinometer_y", float(data['inclinometer']['y']))
    point = point.time(timestamp, WritePrecision.NS)

    try:
        write_api.write(bucket, org, point)
        successful_writes += 1  # Increment the counter
        print(f"Message sent to InfluxDB. -> NUMBER: {successful_writes}")
    except Exception as e:
        print(f"Error sending to InfluxDB: {e}")

def main():
    connection, channel = connect_to_rabbitmq()
    # Listen to each specific antenna queue
    for i in range(5):  # Assuming you have 5 antennas
        queue_name = f'sensor_info_antenna_{i}'
        channel.queue_declare(queue=queue_name, durable=True)
        channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
    
    print(' [*] Waiting for messages from all antenna queues. To exit press CTRL+C')
    
    while True:
        try:
            channel.start_consuming()
        except pika.exceptions.StreamLostError:
            print("Lost connection to RabbitMQ. Attempting to reconnect...")
            connection, channel = connect_to_rabbitmq()
            # Re-declare the consumption setup after reconnection
            for i in range(5):  
                queue_name = f'sensor_info_antenna_{i}'
                channel.queue_declare(queue=queue_name, durable=True)
                channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
        except KeyboardInterrupt:
            print(f"\nTotal successful writes to InfluxDB: {successful_writes}")
            connection.close()
            break


if __name__ == '__main__':
    main()

Docker Compose File:

version: '3.8'

services:
  rabbitmq:
    image: rabbitmq:3-management
    environment:
      RABBITMQ_DEFAULT_USER: guest
      RABBITMQ_DEFAULT_PASS: guest
    ports:
      - "5672:5672"
      - "15672:15672"

  app-1:
    image: luisevoleo/my-python-app-1:v2
    depends_on:
      - rabbitmq
    environment:
      - RABBITMQ_HOST=rabbitmq

  app-2:
    image: luisevoleo/python-app-2:latest
    environment:
      - RABBITMQ_HOST=localhost  
      - INFLUXDB_HOST=OTHER_INFLUX_IP  
      - INFLUXDB_TOKEN=OTHER_INFLUX_TOKEN
      - INFLUXDB_ORG=OTHER_INFLUX_ORG
      - INFLUXDB_BUCKET=OTHER_INFLUX_BUCKET

networks:
  default:
    driver: bridge

(Note: In the actual Docker Compose file, “OTHER_INFLUX_IP”, “OTHER_INFLUX_TOKEN”, “OTHER_INFLUX_ORG”, and “OTHER_INFLUX_BUCKET” are replaced with the real values.)

the log of “my-python-app-1:v2”:

024-01-11 09:29:58  [*] Waiting for messages from all antenna queues. To exit press CTRL+C
2024-01-11 09:29:58 Received message: {'antenna_id': 0, 'timestamp': '2024-01-07 15:49:31', 'gps': {'latitude': 36.864788334924214, 'longitude': -6.251224008665378}, 'temperature': 12.183960983137183, 'humidity': 62.32437121500195, 'wind_speed': 17.817718482363087, 'inclinometer': {'x': 164.14445635809955, 'y': -31.701584384447187}}
2024-01-11 09:30:01 Error sending to InfluxDB: <urllib3.connection.HTTPConnection object at 0x7fa6098faf50>: Failed to establish a new connection: [Errno 113] No route to host
2024-01-11 09:30:01 Received message: {'antenna_id': 0, 'timestamp': '2023-12-22 15:52:22', 'gps': {'latitude': 36.864788334924214, 'longitude': -6.251224008665378}, 'temperature': 0.6879560629965127, 'humidity': 44.81791862827329, 'wind_speed': 24.415517279710393, 'inclinometer': {'x': -153.10337700323, 'y': -139.99972670559453}}
2024-01-11 09:30:04 Error sending to InfluxDB: <urllib3.connection.HTTPConnection object at 0x7fa6098fb280>: Failed to establish a new connection: [Errno 113] No route to host

The container with the script is receiving data but cannot write it to the Dockerized InfluxDB on another machine.

Attempts to Resolve:

-Confirmed InfluxDB is accessible from other machines on the network (I can access it through my browser).
-Tried various Docker network configurations (bridge, host, etc.) without success.

I’m new to Docker and suspect the issue might be with how I’ve Dockerized the Python script. Can anyone help identify what I’m doing wrong or suggest a solution?

Thanks in advance!