Which Python library is commonly used for NETCONF applications?

The choice of ncclient as the correct answer highlights its specific design for facilitating NETCONF operations in Python. ncclient is a Python library that provides a high-level interface for NETCONF client development, allowing users to easily connect to NETCONF servers and perform various operations such as edit-config, get, and close-session.

This library abstracts the complexities involved in handling NETCONF messages, making it easier for developers to build applications that require network device configuration management. It’s equipped with features that support asynchronous operations and provide mechanisms for working with SSH transport for secure communication.

In contrast, other libraries mentioned serve different purposes or are not primarily focused on NETCONF. For example, pyang is mainly used for parsing and validating YANG models but does not directly facilitate NETCONF operations. Similarly, netconf-python might imply functionality related to NETCONF, but it is less commonly referenced in the context of popular libraries compared to ncclient. Lastly, yanglib is focused on handling YANG data models and does not serve as a NETCONF client library.

Thus, ncclient is recognized as the go-to library for developing NETCONF applications in Python, underlining its significance and utility in programming for network automation.