Add support for event hub transport layer proxy

[k-shlomi]

Adds SOCKS5 proxy support for Rust EventHubs client, enabling connections through corporate proxies and restricted network environments.

Changes

Core Implementation

• azure_core_amqp/src/socks5.rs - New SOCKS5 connection module
  • SocksConnection struct with validate_proxy_url(), connect(), mask_credentials()
  • Support for socks5:// and socks5h:// protocols
  • Username/password authentication via URL
  • Automatic credential masking in logs
• azure_core_amqp/src/connection.rs - AMQP integration
  • Modified open_with_stream() to detect SOCKS5 URLs in custom_endpoint
  • Zero breaking changes, backward compatible

Dependencies

• tokio-socks = "0.5"
• tokio-native-tls = "0.3"
• native-tls = "0.2"

Documentation & Examples

• azure_core_amqp/README.md - Added SOCKS5 feature documentation
• eventhubs/examples/eventhubs_socks5_proxy.rs - Complete usage example
• Comprehensive rustdoc with examples and troubleshooting

Usage

  let client = ProducerClient::builder()
      .with_custom_endpoint("socks5h://proxy.corp.com:1080")
      .open(host, eventhub, credential)
      .await?;

Resolves enterprise customer requirements for proxy support in restricted network environments.

[github-actions]

Thank you for your contribution @k-shlomi! We will review the pull request and get back to you soon.

[k-shlomi]

@microsoft-github-policy-service agree company="Sweet Security"

[heaths]

A few notes, but @LarryOsterman should definitely have a look. Thanks for the contribution!

[LarryOsterman]

/azp run rust - eventhubs - weekly

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[LarryOsterman]

In general, I'm singularly impressed. I have one significant concern, which is that I believe that these new tests will fail in our weekly test runs because we run our tests with --all-features and the CI pipeline doesn't have a SOCKS5 proxy available to work.

Also I'd like to have someone from the EventHubs service team take a look to confirm that they want SOCKS5 proxy support as a feature (it's complicated).

[k-shlomi]

Hi @heaths and @LarryOsterman
thank you for the review.
I believe I addressed all your comments. let me know if anything else is needed.

[heaths]

@weshaggard @hallipr what's going on with the vcpkg install on Windows?

From the logs,

%VCPKG_BINARY_SOURCES%: error: invalid argument: binary config 'azblob' requires a SAS token without a preceeding '?' as the second argument

We're using the same setup that other repos are using, so did something break recently?

[heaths]

@k-shlomi please address my comments as well. See our root CONTRIBUTING.md for more information as well.

[k-shlomi]

@heaths I believe I did fix your comments. can you point me out to comments I missed?

[weshaggard]

@weshaggard @hallipr what's going on with the vcpkg install on Windows?

From the logs,

%VCPKG_BINARY_SOURCES%: error: invalid argument: binary config 'azblob' requires a SAS token without a preceeding '?' as the second argument

We're using the same setup that other repos are using, so did something break recently?

@danieljurek is investigating the vcpkg issue.

[danieljurek]

Notes from investigation so far:

• vcpkg install shouldn't be failing here
• Other pipelines are not failing because vcpkg install is invoked differently
• Successful invocations in rust - pullrequest use vcpkg at version 2025-07-21-d4b65a2b83ae6c3526acd1c6f3b51aff2a884533, failing pipeline runs are showing version 2025-09-03-4580816534ed8fd9634ac83d46471440edd82dfe
• There was a recent update to the image that moved vcpkg up. Looks like vcpkg is running from the image.

[danieljurek]

There was a breaking change to binary caching for vcpkg in this version. I have a fix working locally... PR coming soon

[danieljurek]

Fix is in. Rebase on main then push to re-run and get past the vcpkg install issues.

[heaths]

You can't take direct dependencies in a crate. There are also some sanitization concerns.

[k-shlomi]

@heaths one question for you in regards to your last comments.
fixed the rest
pulled from main so now build passes

[heaths]

I don't see a question I haven't answered already. Could you resolve PR comments as you fix/respond to them? Might be easier to see what's still considered an open issue. That's how we do it on our team.

[k-shlomi]

@heaths I missed your comment about making sanitize public a few days ago... fixed it now.
could you verify I did it as you meant to?
also, I resolved the comments
I also pulled from main to make sure the PR is up to date.
hopefully, that will resolve all issues that were still open.

[j7nw4r]

@k-shlomi

Hey. I'm on the Event Hubs team that is managing this sdk going forward. Thanks a lot for this work.

I'm currently speaking with our PM about how to consider this additional functionality. To integrate this change, we'd need to also add it to all of the other language SDKs (and probably the Service Bus SDKs) for parity. We're trying to determine if that (and the maintenance burden) is something we can take on.

[k-shlomi]

got it @j7nw4r thanks.
I will say that for organizations that have deployments on-prem or without direct internet access this probably a required feature.
please keep me posted.