Issue with Message Ordering in ZeroMQ PUSH-PULL Using send_multipart

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Issue with Message Ordering in ZeroMQ PUSH-PULL Using send_multipart

Context: I am currently working on a multi-threaded module where multiple PUSH sockets send messages to a single PULL socket using ZeroMQ. The messages are sent using the send_multipart method in the following format:

send_socket.send_multipart([msg1, msg2])

• msg1: JSON data
• msg2: JPEG byte data

On the receiver side, I am using: x = receive_socket.recv_multipart() . I expect x[0] to always contain the JSON data (msg1), and x[1] to contain the JPEG bytes (msg2). However, in some cases, I am receiving the JPEG bytes as x[0], causing message misalignment. Current Setup:

Messaging Pattern: PUSH-PULL
Multiple PUSH sockets sending data to a single PULL socket

Questions:

• Is there a more suitable messaging pattern in ZeroMQ that can ensure message ordering while handling multiple senders?
• Are there any techniques or configurations I should apply to prevent message parts from arriving in the wrong order?

Any insights or suggestions would be greatly appreciated.

Thank you!