[Windows] PowerShell script added to start proxies for front-end UI (k…

…ubeflow#2835)

* Powershell script added to start proxies for front-end UI

* Commented code

* Simplified based on edits from kubeflow#2836

frontend/start-proxies.ps1

@@ -0,0 +1,75 @@
+#!/usr/env powershell
+
+function Write-Log() {
+    [CmdletBinding()]
+    param([Parameter(ValueFromPipeline=$true,Mandatory=$True)]$Text,[Switch]$NoSign,[Switch]$PlainText,[Switch]$PassThru)
+    begin {$TT = @()}
+    Process {$TT += ,$Text}
+    END {
+        $Blue = $(if ($WRITE_AP_LEGACY_COLORS){3}else{'Blue'})
+        if ($TT.count -eq 1) {$TT = $TT[0]};$Text = $TT
+        if ($text.count -gt 1 -or $text.GetType().Name -match "\[\]$") {return $Text |?{"$_"}| % {Write-AP $_ -NoSign:$NoSign -PlainText:$PlainText}}
+        if (!$text -or $text -notmatch "^((?<NNL>x)|(?<NS>ns?)){0,2}(?<t>\>*)(?<s>[+\-!\*\#\@_])(?<w>.*)") {return $Text}
+        $tb  = "    "*$Matches.t.length;
+        $Col = @{'+'='2';'-'='12';'!'='14';'*'=$Blue;'#'='DarkGray';'@'='Gray';'_'='white'}[($Sign = $Matches.S)]
+        if (!$Col) {Throw "Incorrect Sign [$Sign] Passed!"}
+        $Sign = $(if ($NoSign -or $Matches.NS) {""} else {"[$Sign] "})
+        $Data = "$tb$Sign$($Matches.W)";if (!$Data) {return}
+        if ($PlainText) {return $Data}
+        Write-Host -NoNewLine:$([bool]$Matches.NNL) -f $Col $Data
+        if ($PassThru) {$Data}
+    }
+}
+
+function Dep-Require([Parameter(Mandatory=$True)][Alias("Functionality","Library")][String]$Lib, [ScriptBlock]$OnFail={}, [Switch]$PassThru) {
+    $Stat = $(switch -regex ($Lib.trim()) {
+        "^dep:(.*)" {
+            $pr = $matches[1]
+            if ($IsLinux -or $IsMacOS) {
+                try {which $pr 2>$null} catch {}
+                break
+            }
+            try {where.exe $pr 2>$null} catch {}
+        }
+        default {Write-Log "!Invalid selector provided [$("$Lib".split(':')[0])]";throw 'BAD_SELECTOR'}
+    })
+    if (!$Stat) {$OnFail.Invoke()}
+    if ($PassThru) {return $Stat}
+}
+
+function Clean-Up {
+    Write-Log "!Stopping background jobs... $args"1
+    # jobs -l
+    $Script:PrA,$Script:PrB | ? {$_} | Stop-Process
+    exit 1
+}
+
+Dep-Require "dep:kubectl" {Write-Log "!You're missing kubectl from your path, please install it / or add it to your PATH"; exit 1}
+Dep-Require "dep:npm" {Write-Log "!You're missing npm from your path, please install it / or add it to your PATH"; exit 1}
+
+$Namespace = if ($Env:NAMESPACE) {$Env:NAMESPACE} else {"kubeflow"}
+Write-Log "*Preparing dev env for KFP frontend"
+
+Write-Log "*Detecting api server pod names..."
+Write-Log "*Compiling node server..."
+pushd server;npm run build;popd
+
+# Frontend dev server proxies api requests to node server listening to
+# localhost:3001 (configured in frontend/package.json -> proxy field).
+#
+# Node server proxies requests further to localhost:3002 or localhost:9090
+# based on what request it is.
+#
+# localhost:3002 port forwards to ml_pipeline api server pod.
+# localhost:9090 port forwards to metadata_envoy pod.
+
+Write-Log "*Starting to port forward backend apis..."
+try {
+    $Script:PrA = Start-Process -ws Hidden -PassThru kubectl "port-forward -n kubeflow svc/metadata-envoy-service 9090:9090"
+    $Script:PrB = Start-Process -ws Hidden -PassThru kubectl "port-forward -n kubeflow svc/ml-pipeline 3002:8888"
+    $env:ML_PIPELINE_SERVICE_PORT = 3002
+    npm run mock:server 3001
+} finally {
+    # This will run even after ctrl+c or cmd+c
+    Clean-Up
+}