Fixed proxy Issue

[raujaiswal]

Context

Issue: Publishing test run data from behind corporate proxy fails with socket timeout error while accessing ufxtcmprodweu21.vstmrblob.vsassets.io:443

Work item link

Icm link

Description

Customers have set-up agent locally behind corporate proxy where they failed to publish test run data and get the below error.

  Microsoft.Azure.Storage.StorageException: A connection attempt failed because the connected party did not properly 
  respond after a period of time, or established connection failed because connected host has failed to respond. 
  (ufxtcmprodweu21.vstmrblob.vsassets.io:443)

Why it happened?

• We are setting the proxy in VSSUtil that helps configure VSS (Azure DevOps) client settings, but it does not globally enforce proxy settings for all HTTP clients in the process.

• WebApi (and other SDKs) often create their own HttpClient or connection objects, which may not automatically pick up the proxy settings from VssUtil unless explicitly configured.
  Example:
  

How is Issue reproduced locally?

We have attempted to recreate by doing the following.

1. Setup up a self-hosted Agent behind a proxy Doc

2. Configure a local proxy using Fiddler.

3. Restrict all outbound traffic to the Agent.Listener and the Agent.Worker processes.

:: Block all outbound for the Agent.Listener
netsh advfirewall firewall add rule name="Block Agent.Listener Outbound" dir=out action=block program="C:\agent\_layout\win-x64\bin\Agent.Listener.exe" enable=yes

:: Block all outbound for the Agent.Worker
netsh advfirewall firewall add rule name="Block Agent.Worker Outbound" dir=out action=block program="C:\agent\_layout\win-x64\bin\Agent.Worker.exe" enable=yes

4. Allow Agent.Listener and the Agent.Worker processes to only access the Local Proxy (127.0.0.1)

netsh advfirewall firewall add rule name="Allow Agent.Listener to Proxy" dir=out action=allow program="C:\agent\_layout\win-x64\bin\Agent.Listener.exe" remoteip=127.0.0.1 enable=yes
netsh advfirewall firewall add rule name="Allow Agent.Worker to Proxy" dir=out action=allow program="C:\agent\_layout\win-x64\bin\Agent.Worker.exe" remoteip=127.0.0.1 enable=yes

5. Configure a test pipeline to use the same vso command as used by the customer to publish a sample TRX file.

   $resultFile = '$(Build.SourcesDirectory)\c984c06c-792d-408e-a73b-a5e0505a9b8e.trx'
   Write-Host "##vso[results.publish type=VsTest;mergeResults=false;publishRunAttachments=true;resultFiles=$resultFile;]"
   

6. By default, Fiddler on starting, sets proxy for entire process running in the system. So, we need to disable it by manipulating.

    Go to setting -> Network&Internet -> edit (use a proxy server)
    change value from http=127.0.0.1:8888;https=127.0.0.1:8888 to http=127.0.0.1:8888;httpsgh=127.0.0.1:8888

Solution:

• ProxyUtil.SetDefaultHttpClientProxy is used to ensure that the default .NET HttpClient (and any new HttpClientHandler instances) are also configured to use the correct proxy. This is necessary because some libraries or SDKs may not use the same static/global settings as VssUtil.

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Risk Assessment (Low / Medium / High)

Medium

Unit Tests Added or Updated (Yes / No)

Indicate whether unit tests were added or modified to reflect the changes.

Added test case in canary repo PR:
https://github.com/microsoft/azure-pipelines-canary/pull/1196

Currently Test case is failing with latest agent Version:
Failure Pipeline Link

Test Case is getting passed when taking Agent from this branch users/raunakjaiswalMS/fixingProxyIssue
Passed Pipeline Link

Additional Testing Performed

List manual or automated tests performed beyond unit tests (e.g., integration, scenario, regression).

Reproducing the issue by locally following above steps: ❌

When default proxy is set to httpClient in worker process only: ✅

When default proxy is set to httpClient in Listener process only: ❌

[Copilot]

Pull Request Overview

This PR addresses a socket timeout error when publishing test run data from behind a corporate proxy by ensuring the default .NET HttpClient is configured with the correct proxy settings.

• Sets the global HttpClient proxy settings in both the Worker and Listener processes.
• Introduces a new ProxyUtil class to centralize proxy configuration for all new HttpClientHandler instances.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Agent.Worker/Worker.cs	Configures the default HttpClient proxy before initializing the VSS client settings.
src/Agent.Sdk/Util/ProxyUtil.cs	Defines a utility to set HttpClient.DefaultProxy for global proxy configuration.
src/Agent.Listener/Agent.cs	Ensures the Listener process also applies the default proxy configuration before client initialization.

[raujaiswal]

/azp run

[azure-pipelines]

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