aspnetcore 3.1 angular project timeout on MacOS

Describe the bug

Creating a new project using dotnet new angular -o my-app does not create a working project. The project stalls on serving the angular frontend, resulting in timeouts.

To Reproduce

1. Create a new angular project using the dotnet cli on MacOS (dotnet new angular -o my-app)
2. Change folder to the new project (cd my-app)
3. Build project (dotnet build)
4. Run project (dotnet run)
5. Open the provided url

What happens: The request hangs for a while (depending on the spa.Options.StartupTimeout set) and then fails.

info: Microsoft.Hosting.Lifetime[0]
      Now listening on: https://localhost:5001
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: http://localhost:5000
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
      Content root path: /Users/stuki/Code/temp/my-app
fail: Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware[1]
      An unhandled exception has occurred while executing the request.
System.TimeoutException: The Angular CLI process did not start listening for requests within the timeout period of 0 seconds. Check the log output for error information.
   at Microsoft.AspNetCore.SpaServices.Extensions.Util.TaskTimeoutExtensions.WithTimeout[T](Task`1 task, TimeSpan timeoutDelay, String message)
   at Microsoft.AspNetCore.SpaServices.Extensions.Proxy.SpaProxy.PerformProxyRequest(HttpContext context, HttpClient httpClient, Task`1 baseUriTask, CancellationToken applicationStoppingToken, Boolean proxy404s)
   at Microsoft.AspNetCore.Builder.SpaProxyingExtensions.<>c__DisplayClass2_0.<<UseProxyToSpaDevelopmentServer>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

On closer inspection, dotnet build does not even install the packages for the angular project.

What I expect to happen: The backend should automatically start the frontend, and render the front page. dotnet build should install npm packages for the frontend project

Further technical details

.NET Core SDK (reflecting any global.json):
 Version:   3.1.100
 Commit:    cd82f021f4

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.15
 OS Platform: Darwin
 RID:         osx.10.15-x64
 Base Path:   /usr/local/share/dotnet/sdk/3.1.100/

Host (useful for support):
  Version: 3.1.0
  Commit:  65f04fb6db

.NET Core SDKs installed:
  2.1.700 [/usr/local/share/dotnet/sdk]
  2.2.301 [/usr/local/share/dotnet/sdk]
  3.0.100 [/usr/local/share/dotnet/sdk]
  3.1.100 [/usr/local/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.0 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.11 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.6 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.0.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

[dcchristopher]

Based on feedback found in the Windows side of things, try this combined approach:

In package.json, under “scripts”, update the “start” script to: echo Starting... && ng serve --host 0.0.0.0

Some folks seem to thing that adding the echo statement helps while others think that the --host attribute helps. I can attest to the first one helping at first, then the second one running with the baton when the first one quit making a difference! … and this is what happens when you involve Microsoft …

UPDATE: Worked once like a champ and then back to normal … I’m thinking @David-Ben-Mesecke is on to something! 😂

[David-Ben-Mesecke]

@David-Ben-Mesecke have you found any solution? I have the same problem…

Sorry for the late reply. I ended up with a workaround that worked for me, simply save a ts file so that the compiler has to recompile the ts code and it works. Given it isn’t a problem that translates into the release, I have not bothered to find out why, yet I suspect that the second time around, it is using the ivy compiler while visual studio is trying to use the old compiler somehow. What is important for me is that this way I get it working and I really do not restart my debug sessions often enough for me to bother about the few extra seconds it takes to compile the code a second time.