Changes needed to get to track 2 for cosmos/python.

cosmos_track2.md

Track 2 changes

CosmosClient:

• Constructor should take a credentials instance.
  • Credentials classes should be created for the different auth modes we support (master keys and resource tokens)
• Connection policy arguments should be flattened out to **kwargs.
• proxy configuration should support the settings/environment variables and take an azure-core ProxyPolicy-like object (https://github.com/Azure/azure-sdk-for-python/blob/f2b072688d3dc688fed3905c558cff1fa0849b91/sdk/core/azure-core/azure/core/pipeline/policies/universal.py#L388)

Most prominent per-service-request args to change:

• RetryOptions should take total_retries (was MaxRetryAttemptCount), timeout (was MaxWaitTimeInSeconds), retry_timeout (was FixedRetryIntervalInMilliseconds)
• additional_headers (was initial_headers).
• Adhere to the exception hierarchy in azure.core.errors
• Adhere to paged protocol (add by_page + continuation_token) for returned list-like responses

Less important/urgent:

• Expand FeedOptions into **kwargs. At a minimum, the feed options parameter should be documented.
• Rename client class type names to have Client suffix.
• Provide distributed tracing spans (add decorator on client methods + synchronized_request._Request)
• Accept a transport object in client constructors (for session sharing etc.)

More controversial, but very obvious name conflicts with other libraries:

• rename read_all_xxx -> list_xxx