To achieve a read-only connection using pymongo, you can set the read_preference parameter to ReadPreference.SECONDARY when creating a client connection. This will ensure that all read operations are directed to secondary nodes in a replica set, effectively ensuring a read-only connection. By setting the read_preference to ReadPreference.SECONDARY, the client will only read from secondary nodes, while still allowing writes to be directed to the primary node. This ensures that no data modifications are made through this read-only connection.

What is a cursor in PyMongo?

In PyMongo, a cursor is an object used to iterate over the results of a query to the database. When a query is executed in PyMongo, the results are returned as a cursor object. The cursor allows the user to iterate over the results and access each document returned by the query. Cursors are commonly used in PyMongo to handle large result sets, as they allow the user to process data one document at a time without having to load the entire result set into memory.

How to configure PyMongo logging?

To configure PyMongo logging, you can use the standard Python logging module to control the logging behavior. Here is an example to configure PyMongo logging:

import logging import pymongo

Set the logging level to DEBUG to see all log messages

logging.basicConfig(level=logging.DEBUG)

Connect to the MongoDB server

client = pymongo.MongoClient('localhost', 27017)

Set the logging level for the pymongo logger to INFO

logging.getLogger('pymongo').setLevel(logging.INFO)

Now you can use the client to interact with the database

db = client['testdb'] collection = db['testcollection']

Perform operations on the database

collection.insert_one({'key': 'value'})

In this example, we set the logging level to DEBUG for the root logger, which will capture all log messages. We then set the logging level to INFO for the 'pymongo' logger, which will only capture log messages from PyMongo at or above the INFO level.

You can customize the logging configuration further by adding additional handlers, formatters, and filters to the logging configuration. For more information on configuring Python logging, refer to the official Python documentation: https://docs.python.org/3/library/logging.html.

How to check if a connection is read-only in PyMongo?

To check if a connection is read-only in PyMongo, you can use the following code snippet:

from pymongo import MongoClient

Connect to the MongoDB server

client = MongoClient('mongodb://localhost:27017')

Get the database

db = client['your_database_name']

Check if the connection is read-only

if db.client.is_mongos: print("Connection is read-only") else: print("Connection is not read-only")

In this code snippet, we are connecting to the MongoDB server and checking if the client is a Mongos instance. Mongos is a special type of MongoDB client that only supports read-only operations. If the client is a Mongos instance, then the connection is read-only. Otherwise, it is not read-only.