MongoDB examples, Replica Set and GridFS
MongoDB Replica Set with Python example
I published a short lab on working with MongoDB replica sets in Python on GitHub https://github.com/k0emt/mongodb_repset_experiment
One thing to note is that I included all of the replica set nodes in the connection information. That is because if "regular" primary node was down at the time of initial connection the code would fail.
The nodes in the replica set will figure out who should be primary and that will happen auto-magically behind the scenes. However, your client code still needs to deal with needing to reconnect.
Adjust the counters if you want to have the client up and running longer while you experiment.
MongoDB GridFS with Java example
Example code for demonstrating GridFS and the metadata field with Java was also published on GitHub https://github.com/k0emt/gridfs_example_java
By utilizing the metadata field you can keep your document metadata with it.