feat: Cosmos DB Change Feed Mode Support

[swapnil-nagar]

Summary

Updated Python Azure Functions library to support Cosmos DB change feed modes (LatestVersion and AllVersionsAndDeletes), aligning with Azure WebJobs Extensions upstream implementation.

Changes

• Type Definitions: Added CosmosDBChangeFeedMode type hint in _cosmosdb.py supporting 'LatestVersion' | 'AllVersionsAndDeletes'
• Module Documentation: Updated CosmosDBConverter and CosmosDBTriggerConverter class docstrings to document change feed mode behavior
• Public API: Exported CosmosDBChangeFeedMode type from main __init__.py for public consumption
• Tests: Added 3 new unit tests validating change feed mode support:
  • test_cosmosdb_change_feed_mode_latest_version_support: Validates LatestVersion mode
  • test_cosmosdb_change_feed_mode_all_versions_and_deletes_support: Validates AllVersionsAndDeletes mode
  • test_cosmosdb_change_feed_mode_type_available: Verifies type availability in public API

Files Modified

• azure/functions/_cosmosdb.py: Added CosmosDBChangeFeedMode type
• azure/functions/cosmosdb.py: Updated documentation, exported type
• azure/functions/__init__.py: Exported and documented CosmosDBChangeFeedMode
• tests/test_cosmosdb.py: Added change feed mode tests

Alignment

This change mirrors the Node.js library v4.16.1 Cosmos DB updates, ensuring consistent change feed support across both runtimes.

[swapnil-nagar]

/azp run

[azure-pipelines]

Commenter does not have sufficient privileges for PR 346 in repo Azure/azure-functions-python-library

[jviau]

I am not familiar with E2E-test situation for this repo, but want to make sure the feature is validated either manually or by tests. A specific scenario to validate for is the incoming payload type when using AllVersionsAndDelete. With LatestVersion it will be T, for AVAD it will be ChangeFeedItem<T>. So the JSON representation of this CSharp class: https://learn.microsoft.com/en-us/dotnet/api/microsoft.azure.cosmos.changefeeditem-1?view=azure-dotnet-preview

[hallvictoria]

Can you add tests for the decorator changes as well? You can add them under tests/decorators/test_cosmosdb.py - for reference, you can look at the Blob decorator tests with the source param (lines 11 - 69):

azure-functions-python-library/tests/decorators/test_blob.py

Line 11 in 2be49d6

def test_blob_trigger_creation_with_no_source(self):

[hallvictoria]

For Jacob's comment, our Cosmos DB E2E tests are defined here, and we use the Cosmos DB emulator.

If this feature is supported in the emulator, you can create a PR to the python worker repo with the new function apps & tests. If the feature is not supported, we can create a follow-up task to update the Cosmos tests when the emulators have this change. Please let me know if you have any questions for testing!

[hallvictoria]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jviau]

@hallvictoria I don't think it is supported in the emulator 😞. That has been the challenge with all my E2E tests also. I manually test with a real CosmosDB then disable the tests before checking in.