Describe your environment

N/A

What happened?

The gRPC channel is not being closed properly, preventing gRPC from shutting down cleanly.

Steps to Reproduce

Please refer to: grpc/grpc#38490 (comment)

Expected Result

gRPC cleanly shutting down.

Actual Result

gRPC not cleanly shutting down.

Additional context

In OTLPExporterMixin, gRPC channel was created directly and passed to _client:

But the channel was not shutdown in shutdown method:

gRPC channel should be closed explicitly with context manager or by calling channel.close() method, example usage:
https://github.com/grpc/grpc/blob/822f9b15191840228d17dc0d305887374150150e/examples/python/helloworld/greeter_client.py#L25-L33

If not explicitly closed, the gRPC channel may prevent gRPC from shutting down cleanly, leading to issues like the one described in: grpc/grpc#38490

Would you like to implement a fix?

None