Python Consul 2 Client (Abandoned)

Common errors

• ModuleNotFoundError: No module named 'python_consul2'

  cause Attempting to import the library using `from python_consul2 import Consul` instead of the correct `from consul import Consul`.
  fix Change your import statement to `from consul import Consul`.

• requests.exceptions.ConnectionError: HTTPConnectionPool(host='localhost', port=8500): Max retries exceeded with url: /v1/kv/my-key?token= (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at ...>: Failed to establish a new connection: [Errno 111] Connection refused'))

  cause The Consul agent is not running, is not accessible from the client, or is running on a different host/port than configured.
  fix Verify that your Consul agent is running and listening on the expected host and port (default: `localhost:8500`). Check firewall rules if connecting remotely. Ensure `CONSUL_HOST` and `CONSUL_PORT` environment variables or constructor arguments are correct.

• AttributeError: 'Consul' object has no attribute 'agent'

  cause This specific error might occur if the library version is extremely old or if you're mixing `python-consul2` with expectations from `python-consul`. More commonly, it signifies attempting to call an API method that does not exist in the version of the client library you are using, or it has been renamed/removed.
  fix Consult the `python-consul2` source code or documentation (if any) for available methods. If using an older Consul API, consider migrating to `python-consul` for better compatibility with current Consul versions and a more actively maintained API surface.

Warnings

• breaking This library (`python-consul2`) is an abandoned fork of `python-consul`. It has not been updated since 2018, leading to potential compatibility issues with newer Python versions, Consul API changes, and lack of critical bug fixes or security updates. It is strongly recommended to use the actively maintained `python-consul` library instead.
  Fix: Migrate to the `python-consul` library (`pip install python-consul`). Be aware of potential minor API differences.
• gotcha The package is installed as `python-consul2` but the correct import statement is `from consul import Consul`. Trying to import directly from `python_consul2` will result in a `ModuleNotFoundError`.
  Fix: Always use `from consul import Consul` or `import consul`.
• gotcha Due to its abandonment, `python-consul2` may not support features or API changes introduced in Consul versions released after 2018 (e.g., Consul 1.5+). Attempting to use newer Consul features might result in `AttributeError` or unexpected behavior.
  Fix: Use the actively maintained `python-consul` library which keeps up-to-date with Consul API changes, or ensure you are running an older Consul version compatible with this client.

Install

• pip install python-consul2 Install with pip

Imports

• Consul
  wrong:

  from python_consul2 import Consul

  correct:

  from consul import Consul

  Despite the package name `python-consul2`, the top-level import module is `consul`.

Quickstart

This quickstart demonstrates how to initialize the Consul client, put and get key-value pairs from the KV store, and list keys by prefix. Ensure a Consul agent is running and accessible at the specified host and port (default: localhost:8500).

import os
import consul

# Configuration for Consul connection
CONSUL_HOST = os.environ.get('CONSUL_HOST', 'localhost')
CONSUL_PORT = int(os.environ.get('CONSUL_PORT', '8500'))

try:
    # Initialize Consul client
    c = consul.Consul(host=CONSUL_HOST, port=CONSUL_PORT)

    # Example 1: Put a key-value pair
    key = 'my-app/config/feature-flag'
    value = 'true'
    success = c.kv.put(key, value)
    if success:
        print(f"Successfully set key '{key}' to '{value}'")

    # Example 2: Get a key-value pair
    index, data = c.kv.get(key)
    if data:
        retrieved_value = data['Value'].decode('utf-8')
        print(f"Retrieved key '{key}': '{retrieved_value}'")
    else:
        print(f"Key '{key}' not found.")

    # Example 3: List keys under a prefix
    index, data = c.kv.get('my-app/', recurse=True)
    if data:
        print(f"Keys under 'my-app/':")
        for item in data:
            print(f"  - {item['Key']}: {item['Value'].decode('utf-8') if item['Value'] else 'N/A'}")

except Exception as e:
    print(f"An error occurred: {e}")
    print("Ensure Consul agent is running and accessible at {CONSUL_HOST}:{CONSUL_PORT}")