Before you start writing the script, you need to determine which data you want to migrate from MongoDB to Redis. This could be a specific collection or specific documents within a collection.

First, you need to establish a connection to MongoDB and select the database and collection you want to work with.

from pymongo import MongoClient

# MongoDB connection parameters

mongo_host = 'localhost'

mongo_port = 27017

mongo_db_name = 'your_db_name'

mongo_collection_name = 'your_collection_name'

# Establish a connection to MongoDB

mongo_client = MongoClient(mongo_host, mongo_port)

mongo_db = mongo_client[mongo_db_name]

mongo_collection = mongo_db[mongo_collection_name]

Similarly, establish a connection to the Redis server.

import redis

# Redis connection parameters

redis_host = 'localhost'

redis_port = 6379

# Establish a connection to Redis

redis_client = redis.StrictRedis(host=redis_host, port=redis_port, decode_responses=True)

Fetch the data from MongoDB that you want to move to Redis. For the sake of this example, let's assume you want to migrate all documents from a collection.

# Fetch data from MongoDB

documents = mongo_collection.find()

Now, loop through the fetched documents and insert them into Redis. The way you insert data into Redis will depend on the structure of your data and how you want to use it within Redis (e.g., as strings, hashes, lists, sets, etc.).

for doc in documents:

    # Assume the document has an '_id' field that will be used as the Redis key

    redis_key = str(doc['_id'])

    # Remove the '_id' field from the document since it's not needed in Redis

    doc.pop('_id', None)

    # Insert the document as a hash in Redis

    redis_client.hmset(redis_key, doc)

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If your MongoDB documents contain complex data types that are not natively supported by Redis, you'll need to serialize the data before inserting it. You can use json.dumps() to convert the document to a JSON string.

import json

for doc in documents:

    redis_key = str(doc['_id'])

    doc.pop('_id', None)

    # Serialize the document to a JSON string

    serialized_doc = json.dumps(doc)

    # Insert the serialized document as a string in Redis

    redis_client.set(redis_key, serialized_doc)

After the script has run, you should verify that the data has been successfully migrated to Redis.

for doc in documents:

    redis_key = str(doc['_id'])

    if not redis_client.exists(redis_key):

        print(f"Document with key {redis_key} was not found in Redis.")

    else:

        print(f"Document with key {redis_key} exists in Redis.")

Close the connections to both MongoDB and Redis once the migration is complete.

mongo_client.close()

redis_client.close()

Run your script. Make sure to handle exceptions and errors appropriately, especially for production environments.

if __name__ == '__main__':

    try:

        # Your data migration code here

        pass

    except Exception as e:

        print(f"An error occurred: {e}")

    finally:

        # Clean up

        mongo_client.close()

        redis_client.close()