Synchronization of Multiple Sources

If you need to receive messages from multiple sources in a synchronized way it could be difficult to, for example, receive the first message of each receiver as soon as it is available in one single task. A naive approach like this will not work:

message = await receiver1.receive()
print(f"Received from channel1: {message}")

message = await receiver2.receive()
print(f"Received from channel2: {message}")

The problem is that if the first message is not available in channel1 but in channel2, the program will be blocked until a message is available in channel1, but you probably want to receive the first message from channel2 as soon as it is available.

Frequenz Channels provides two tools to solve this issue: merge() and select().