Append failing eBPF dependency status to GPA service start failure error message

[srikrishnaveturi]

Overview

When GuestProxyAgent fails to start due to missing or unhealthy eBPF dependencies (SCM errors 1068 / 1075), the error log previously only contained the raw SCM error with no actionable context:

Service 'GuestProxyAgent' failed to start after 4 attempts

This change queries EbpfCore and NetEbpfExt immediately after a start failure and appends any non-Running services to the error message, so on-call responders can identify the root cause without manual investigation.

High Level Code Changes

proxy_agent_setup/src/main.rs

• Added a failing_ebpf_deps_message pure helper function (Windows-only) that takes two ServiceStatusInfo values and returns None when both are healthy, or Some("Failing eBPF dependencies: ...") listing only the non-Running ones.
• On start failure, the helper is called and its output appended inline to the single write_error call — no extra log lines when eBPF is healthy.
• Added 5 unit tests covering all meaningful state combinations: both running (None), both missing, each individually missing or stopped.

Testing

Manually replaced proxy_agent_setup.exe in a VM, renamed the eBPF setup script to prevent auto-recovery, deleted both eBPF driver services, then ran proxy_agent_setup.exe install:

C:\Packages\Plugins\Microsoft.CPlat.ProxyAgent.ProxyAgentWindowsTest\1.0.41\ProxyAgent>sc delete EbpfCore
[SC] DeleteService SUCCESS

C:\Packages\Plugins\Microsoft.CPlat.ProxyAgent.ProxyAgentWindowsTest\1.0.41\ProxyAgent>sc delete NetEbpfExt
[SC] DeleteService SUCCESS

C:\Packages\Plugins\Microsoft.CPlat.ProxyAgent.ProxyAgentWindowsTest\1.0.41\ProxyAgent>proxy_agent_setup.exe install


============== ProxyAgent Setup Tool (9.9.9.0) is starting with args: install ==============
Stopped service GuestProxyAgent successfully
[... file copy output ...]
Install service GuestProxyAgent successfully
ebpf_setup: check_service_installed: service: eBPFSvc successfully queried.
Update service GuestProxyAgent with more service_dependency successfully
Service 'GuestProxyAgent' failed to start after 4 attempts
Service GuestProxyAgent start failed, error: WindowsService(Winapi(Os { code: 1068, kind: Uncategorized, message: "The dependency service or group failed to start." }), Os { code: 1068, kind: Uncategorized, message: "The dependency service or group failed to start." }). Failing eBPF dependencies: service: EbpfCore status query failed, service may not be installed; service: NetEbpfExt status query failed, service may not be installed