How to listen for changes to a MongoDB collection?

Question

I\'m creating a sort of background job queue system with MongoDB as the data store. How can I \"listen\" for inserts to a MongoDB collection before spawning workers to proce

Answer 1

Since MongoDB 3.6 there will be a new notifications API called Change Streams which you can use for this. See this blog post for an example. Example from it:

cursor = client.my_db.my_collection.changes([
    {'$match': {
        'operationType': {'$in': ['insert', 'replace']}
    }},
    {'$match': {
        'newDocument.n': {'$gte': 1}
    }}
])

# Loops forever.
for change in cursor:
    print(change['newDocument'])