Litellm fix json serialize alreting 2

[Sameerlite]

Title

Fix Redis serialization error in SlackAlerting outage alerts

Relevant issues

Fixes LIT-1291

Pre-Submission checklist

Please complete all items before asking a LiteLLM maintainer to review your PR

• I have Added testing in the tests/litellm/ directory, Adding at least 1 test is a hard requirement - see details
• I have added a screenshot of my new test passing locally
• My PR passes all unit tests on make test-unit
• My PR's scope is as isolated as possible, it only solves 1 specific problem

Type

🐛 Bug Fix

Changes

Problem

When Vertex AI requests timeout (408 errors), LiteLLM attempts to cache outage alert data but fails with:

LiteLLM Redis Caching: async set() - Got exception from REDIS Object of type set is not JSON serializable

This occurs because ProviderRegionOutageModel.deployment_ids is a Python set object, which cannot be JSON serialized for Redis storage.

Solution

Added two helper methods to handle set/list conversion:

• _prepare_outage_value_for_cache(): Converts sets to lists before caching
• _restore_outage_value_from_cache(): Converts lists back to sets after retrieval

Changes Made

• Added helper methods in SlackAlerting class for set/list conversion
• Updated region_outage_alerts() method to use helper methods for caching
• Updated outage_alerts() method to use helper methods for caching

[vercel]

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Project	Deployment	Preview	Comments	Updated (UTC)
litellm	Ready	Preview	Comment	Oct 20, 2025 6:48pm

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[Sameerlite]

Closes #15648