Warn when browser is already running before starting DevTools

[karpikpl]

Description

I cannot make devtools to work, even though there are no errors logged in devproxy

Expected behaviour

opening http://localhost:9222/devtools/inspector.html?ws=localhost:62690 opens devtools

Actual behaviour

Connection refused. Nothing listening on 9222?

Steps to reproduce

devproxy -c "C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\presets\microsoft-graph.json" --record --log-level Trace

with

  "plugins": [
      {
        "name": "DevToolsPlugin",
        "enabled": true,
        "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
        "configSection": "devTools"
      },

Dev Proxy Version

0.17.1

Operating system (environment)

Windows

Shell

PowerShell

Configuration file

{
  "$schema": "https://raw.githubusercontent.com/microsoft/dev-proxy/main/schemas/v0.17.1/rc.schema.json",
  "plugins": [
      {
        "name": "DevToolsPlugin",
        "enabled": true,
        "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
        "configSection": "devTools"
      },
    {
      "name": "GraphSelectGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll"
    },
    {
      "name": "GraphBetaSupportGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
      "urlsToWatch": [
        "https://graph.microsoft.com/beta/*",
        "https://graph.microsoft.us/beta/*",
        "https://dod-graph.microsoft.us/beta/*",
        "https://microsoftgraph.chinacloudapi.cn/beta/*"
      ]
    },
    {
      "name": "GraphConnectorGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
      "urlsToWatch": [
        "https://graph.microsoft.com/*/external/connections/*/schema",
        "https://graph.microsoft.us/*/external/connections/*/schema",
        "https://dod-graph.microsoft.us/*/external/connections/*/schema",
        "https://microsoftgraph.chinacloudapi.cn/*/external/connections/*/schema"
      ]
    },
    {
      "name": "GraphSdkGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll"
    },
    {
      "name": "ODataPagingGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll"
    },
    {
      "name": "GraphClientRequestIdGuidancePlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll"
    },
    {
      "name": "GraphRandomErrorPlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
      "configSection": "graphRandomErrorsPlugin"
    },
    {
      "name": "ExecutionSummaryPlugin",
      "enabled": true,
      "pluginPath": "~appFolder/plugins/dev-proxy-plugins.dll",
      "configSection": "executionSummaryPlugin"
    }
  ],
  "urlsToWatch": [
    "https://graph.microsoft.com/v1.0/*",
    "https://graph.microsoft.com/beta/*",
    "https://graph.microsoft.us/v1.0/*",
    "https://graph.microsoft.us/beta/*",
    "https://dod-graph.microsoft.us/v1.0/*",
    "https://dod-graph.microsoft.us/beta/*",
    "https://microsoftgraph.chinacloudapi.cn/v1.0/*",
    "https://microsoftgraph.chinacloudapi.cn/beta/*"
  ],
  "graphRandomErrorsPlugin": {
    "allowedErrors": [ 429, 500, 502, 503, 504, 507 ]
  },
  "executionSummaryPlugin": {
    "groupBy": "url"
  },
  "devTools": {
    "preferredBrowser": "Chrome"
  },
  "rate": 50,
  "labelMode": "text",
  "logLevel": "information"
}

Additional Info

Log output:

PS C:\Users\piotrkarpala> devproxy -c "C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\presets\microsoft-graph.json" --record --log-level Trace
Loading plugin DevToolsPlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin DevToolsPlugin...
DevTools available at http://localhost:9222/devtools/inspector.html?ws=localhost:62690
Plugin DevToolsPlugin registered.
Loading plugin GraphSelectGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphSelectGuidancePlugin...
Plugin GraphSelectGuidancePlugin registered.
Loading plugin GraphBetaSupportGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphBetaSupportGuidancePlugin...
Plugin GraphBetaSupportGuidancePlugin registered.
Loading plugin GraphConnectorGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphConnectorGuidancePlugin...
Plugin GraphConnectorGuidancePlugin registered.
Loading plugin GraphSdkGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphSdkGuidancePlugin...
Plugin GraphSdkGuidancePlugin registered.
Loading plugin ODataPagingGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin ODataPagingGuidancePlugin...
Plugin ODataPagingGuidancePlugin registered.
Loading plugin GraphClientRequestIdGuidancePlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphClientRequestIdGuidancePlugin...
Plugin GraphClientRequestIdGuidancePlugin registered.
Loading plugin GraphRandomErrorPlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin GraphRandomErrorPlugin...
Plugin GraphRandomErrorPlugin registered.
Loading plugin ExecutionSummaryPlugin from: C:\Users\piotrkarpala\AppData\Local\Programs\Dev Proxy\plugins\dev-proxy-plugins.dll
Registering plugin ExecutionSummaryPlugin...
Plugin ExecutionSummaryPlugin registered.
Listening on 127.0.0.1:8000...
Set endpoint at Ip 127.0.0.1 and port: 8000 as System HTTP Proxy
Set endpoint at Ip 127.0.0.1 and port: 8000 as System HTTPS Proxy
Hotkeys: issue (w)eb request, (r)ecord, (s)top recording, (c)lear screen
Press CTRL+C to stop Dev Proxy

◉ Recording...
 request     GET https://graph.microsoft.com/v1.0/users
 warning   ╭ To help Microsoft investigate errors, to each request to Microsoft Graph
           │ add the client-request-id header with a unique GUID.
           │ More info at https://aka.ms/devproxy/guidance/client-request-id
           ╰ GET https://graph.microsoft.com/v1.0/users

[waldekmastykarz]

Thank you for reaching out @karpikpl and sorry to hear you're having trouble. Before starting Dev Proxy, have you closed all instances of Chrome (including all processes)? If there's a Chrome process active before you start Dev Proxy, Proxy won't be able to start Dev Tools with Chrome.

[karpikpl]

I think that was it. I was expecting that even if the browser did not open - the service would still be there, listening on 9222.

Is there a way to capture this issue and throw an error?
I could PR it if you point me in the right direction :)

[waldekmastykarz]

Cool! We'd appreciate your help! Here, we're resolving browser to its x-plat process name:

dev-proxy/dev-proxy-plugins/Inspection/DevToolsPlugin.cs

Lines 63 to 74 in 2a6ca02

	return configuration.PreferredBrowser switch
	{
	PreferredBrowser.Chrome => RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
	? Environment.ExpandEnvironmentVariables(@"%ProgramFiles%\Google\Chrome\Application\chrome.exe")
	: "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
	PreferredBrowser.EdgeDev => RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
	? Environment.ExpandEnvironmentVariables(@"%ProgramFiles(x86)%\Microsoft\Edge Dev\Application\msedge.exe")
	: "/Applications/Microsoft Edge Dev.app/Contents/MacOS/Microsoft Edge Dev",
	_ => RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
	? Environment.ExpandEnvironmentVariables(@"%ProgramFiles(x86)%\Microsoft\Edge\Application\msedge.exe")
	: "/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge"
	};

.

We'd need to extend the InitInspector method (

dev-proxy/dev-proxy-plugins/Inspection/DevToolsPlugin.cs

Line 77 in 2a6ca02

private void InitInspector()

) to check for any instances of the process and show a warning when we find one. Let's keep in mind that the code we write for this needs to work at least on macOS and Windows.