[Internal] [FaultInjection] ThinClient: Fixes payload of injected errors for requests going to ThinClient Proxy

[NaluTripician]

Pull Request Template

Description

This fixes the payload of injected errors for requests going to the thin client to ensure that diagnostics contain the correct information.

This PR, move the injection point of the error from the CosmosHttpClientCore to the ThinClientStoreClient. This allows for a direct return of the response without the need to use the thin client serialization/deserialization on the faulty response generation/return.

To enable fault injection for thin client mode, create a fault injection rule the same way you would for any other gateway mode fault injection rule. Then, enable thin client mode for the client via the enable thin client environment variable.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Closing issues

To automatically close an issue: closes #5342

[kundadebdatta]

Please add more detailed description on the usage.

[Copilot]

Pull Request Overview

This PR fixes the payload of injected errors for requests going to ThinClient Proxy to ensure diagnostics contain correct information. The error injection point is moved from CosmosHttpClientCore to ThinClientStoreClient to allow direct response return without using thin client serialization/deserialization on faulty responses.

• Moves fault injection from HTTP client layer to ThinClient store client layer
• Updates error response formatting to match proxy call expectations with proper JSON payloads
• Removes unnecessary header setting logic from HTTP client core

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
ThinClientStoreClient.cs	Adds chaos interceptor integration and fault injection handling at the store client level
CosmosHttpClientCore.cs	Removes fault injection header setting logic that is no longer needed
GatewayStoreModel.cs	Passes chaos interceptor to ThinClientStoreClient constructor
DocumentClient.cs	Passes chaos interceptor parameter to GatewayStoreModel
FaultInjectionServerErrorResultInternal.cs	Updates error response formatting for proxy calls with proper JSON payloads and HTTP versions
FaultInjectionRuleProcessor.cs	Passes global endpoint manager to fault injection server error result

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[kundadebdatta]

LGTM

[xinlian12]

LGTM, thanks 👍

[FabianMeiswinkel]

LGTM - Thanks