Timeout improvements

[felipediel]

Problem 1: False-positive NetworkTimeout() exception

Some operations are blocking. When we send a long RF code, the device takes a long time to respond, but it doesn't mean the connection timed out.

Let's take this code for example:

b64: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

It takes 4.5s until we get a response from the device. This will prevent the device from sending the code repeatedly when the timeout blows in the inner loop, but even with that fix we need to increase the timeout to avoid throwing a false-positive NetworkTimeout() in the end.

Problem 2: Multi-threads, lock and timeout

When we call device.send_data() (operation A) from thread A and then call device.send_data() (operation B) from thread B before the operation A is finished, we're going to wait for operation A to finish here. But we are starting to count operation B outside the lock, so we can timeout operation B even before it is started. My suggestion is to only start counting inside the lock.

Proposed changes

• Use a context manager to deal with conn.close() in device.send_packet().
• Remove the SO_REUSEADDR option because we don't need to reuse the port. The OS will bind() to any available port.
• Create a retry_intvl parameter in device.send_packet() to expose the interval, in seconds, between retries.
• Increase the retry_intvl in rm and rm4.send_data() from 1 to 5 to avoid running out of time on blocking operations like sending long RF codes.
• Start the timer inside the lock to avoid running out of time on blocking operations.

[KTibow]

What happened to

conn.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

[felipediel]

I don't think we need this option here because we are not binding to a specific port. The OS will bind to any available port, so we don't need to reuse anything.