Timeout Option for SchemaRegistryClient

[snazzyfox]

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:

• [x] 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
• [x] 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

[zschumacher]

Any update on this? It is still an issue for us at @Simplebet and probably others

[jliunyu]

We are looking into this issue.

[slominskir]

Duplicate of https://github.com/confluentinc/confluent-kafka-python/issues/622

[chipola]

It looks like there's a PR submitted, can we get someone from the team to take a look? cc: @jliunyu