named the buildkite windows agents

containers/agent-windows-buildkite/Dockerfile

@@ -9,9 +9,5 @@ FROM gcr.io/llvm-premerge-checks/agent-windows
 ARG token
 ENV BUILDKITE_BUILD_PATH=C:\ws\bk
 
-#TODO(kuhnel): use the host machine name in the agent name.
-# This needs to be set during run time in the start_agent.ps1 script.
-ENV BUILDKITE_AGENT_NAME=win-vs17
-
 COPY start_agent.ps1 C:\scripts\
 CMD "powershell C:\scripts\start_agent.ps1"

containers/agent-windows-buildkite/start_agent.ps1

@@ -3,4 +3,7 @@ $Env:buildkiteAgentToken = [IO.File]::ReadAllText("C:\credentials\buildkite-toke
 #Set-ExecutionPolicy Bypass -Scope Process -Force 
 iex ((New-Object System.Net.WebClient).DownloadString('https://raw.githubusercontent.com/buildkite/agent/master/install.ps1'))
 
+# use the name of the host machine as name for the agent in buildkite
+$env:BUILDKITE_AGENT_NAME="win-vs17 $env:PARENT_HOSTNAME"
+
 C:\buildkite-agent\bin\buildkite-agent.exe start --tags "os=windows"