Description

SchemaRegistryClient does not supply a timeout to the underlying calls to requests. If a network issue causes no data to be returned (such as firewall/security group misconfiguration), the client will wait forever instead of raising a timeout error. This essentially causes the application to hang.

We should add a new configuration option to SchemaRegistryClient that sets the timeout so that an error may be raised/caught in these situations.

How to reproduce

With a blackhole server running locally, for example on port 8000

from confluent_kafka.schema_registry import SchemaRegistryClient
client = SchemaRegistryClient({'url': 'localhost:8000'})
client.get_subjects()  # this will hang forever

Checklist

Please provide the following information:

• confluent-kafka-python and librdkafka version (confluent_kafka.version() and confluent_kafka.libversion()): both 1.4.2
• Apache Kafka broker version: irrelevant
• Client configuration: {...}: irrelevant
• Operating system: Probably irrelevant since schema registry client is pure python, but reproduced on ubuntu 20.04, amazon linux 2, and windows 10
• Provide client logs (with 'debug': '..' as necessary)
• Provide broker log excerpts
• Critical issue