Running multiple parallel instances of a .NET Core App using dotnet run

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I'm getting the following error:

C:\Program Files\dotnet\sdk\2.0.3\Microsoft.Common.CurrentVersion.targets(4052,5): warning MSB3026: Could not copy "obj\Debug\netcoreapp2.0\MyApp.dll" to "bin\Debug\netcoreapp2.0\MyApp.dll". Beginning retry 1 in 1000ms. The process cannot access the file 'C:\stackoverflow\MyApp\bin\Debug\netcoreapp2.0\MyApp.dll' because it is being used by another process. [C:\stackoverflow\MyApp\MyApp.csproj]

When trying to use dotnet run multiple times on the same project from different terminals. How do you easily run multiple instances of the same app while developing, without having to copy the folder?

If I start both at exactly the same time, it sometimes works :/

I've used bat file to run 6 instances of app in one time. Only problem was when I started build of application and immediately run script. So I think you should make sure that build process ended. And then run you bat file with for example dotnet run repeated six times. Your app should be built to execute this file.

start /d "." dotnet run args
start /d "." dotnet run args
start /d "." dotnet run args
start /d "." dotnet run args
start /d "." dotnet run args
start /d "." dotnet run args

Before tasks, events were one of the methods of executing jobs asynchronously and Multiple processes can be started and awaited this way : You can use a deployment manifest to run .NET Core applications on Elastic Beanstalk. . NET Core is a cross-platform version of .NET that comes with a command line tool ( dotnet ) that you can use to generate an application, run it locally, and prepare it for publishing.

I had the same problem and solved it using --no-build option:

dotnet run --no-build <path to .dll> <args>

Please take a look at: MSDN documentation

NET Core pipelines from within the same main application, running on top of the So – in this article – when we talk about multiple parallel pipelines, we But what if you wanted to run two separate MVC pipelines, each with it's own Inside that extension method, we will first create an IWebHost instance. Running multiple independent ASP.NET Core pipelines side by side in the same application The other day I started looking into a problem of being able to run several independent ASP.NET Core pipelines from within the same main application, running on top of the same Kestrel server.

There is one more hacky way by setting unique name of build configuration like this:

start /d "." dotnet run -c Instance1 args
start /d "." dotnet run -c Instance2 args
start /d "." dotnet run -c Instance3 args
start /d "." dotnet run -c Instance4 args
start /d "." dotnet run -c Instance5 args
start /d "." dotnet run -c Instance6 args

Moreover, you don't have to specify all your build configurations in the project file (MyApp.csproj).

Without setting the name of configuration explicitly the default value is used, which is Debug. That is why the DLLs within Debug folder are locked.

The dotnet test command is used to execute unit tests in a given project. solution and runs a test host application for each test project in the solution. For multi-targeted projects, tests are run for each targeted framework. So, running dotnet <path_to_your_application>.dll will not spawn multiple processes. Since 2.1.300, we actually have other servers that are long running: we have vbcscompiler, which is the one you were referring to above. We have the razor compiler and msbuild node re-use server. To prevent all of them from running, you can do the following:

The best thing in development time I've found is dotnet watch commandline tool.

You could have one bat file which will start multiple dotnet watch run <project> commands like in MateuszWkDev's answer.

Running in watch mode doesn't blocks files from editing and will rebuild and rerun applications once you'll edit your source files automatically.

Suppose you have bat file in src folder which has SomeProject, OtherProject and YetAnotherProject folders, which are contains csproj-files. Then bat file could looks like:

start /d "%~dp0\SomeProject"       dotnet watch run SomeProject
start /d "%~dp0\OtherProject"      dotnet watch run OtherProject
start /d "%~dp0\YetAnotherProject" dotnet watch run YetAnotherProject

Once you run this bat file, you'll got three terminals running dotnet watch run <project> commands.

In .NET Core, tasks are the main abstraction for concurrent interaction in a desktop application or process other requests in a server application, instead care of queuing and executing the tasks using the thread pool threads. To run multiple tasks concurrently, just start them consecutively and collect  The dotnet run command is used in the context of projects, not built assemblies. If you're trying to run a framework-dependent application DLL instead, you must use dotnet without a command. For example, to run myapp.dll, use: dotnet myapp.dll For more information on the dotnet driver, see the .NET Core Command Line Tools (CLI) topic.

I have an issue where "dotnet test" is running assemblies in parallel. and [​assembly: LevelOfParallelism(1)] and also running with the dotnet test CLI It even looks like dotnet test is firing up 2 instances of the tester process NETCoreApp,Version=v2.2) Microsoft (R) Test Execution Command Line Tool  In order to have a better control while versioning or changing your app guid, you can use: string appGuid = ( (GuidAttribute)Assembly.GetExecutingAssembly ().GetCustomAttributes (typeof (GuidAttribute), true) [0]).Value; which will get the executing assembly's guid – ciosoriog Jun 17 '16 at 17:04. |.

Build highly performant, multi-threaded, and concurrent applications using C# 7 and .NET When an application runs, the GC register itself receives an event notification NET Core, there is no executable file generated, we can use dotnet cli  Using CMD you can run a console .net core project if .net core SDK is installed in your machine : To run console project using windows command-Line, choose the specific path from your directory and type following below command. dotnet run. share. Share a link to this answer.

It's amazing how quickly a .net core app can be deployed and tested in a real hosting environment. Running in parallel is the key here because you can make many requests and wrong you will get an AggregatedException with possibly multiple exceptions, Let's run requests in parallel, but smarter. Running a .NET Core app on the traditional .NET Framework 4.5.x. If you just want to run your .NET Core app (like an ASP.NET Core Web API service) on the traditional .NET Framework, you can do it by changing adding/changing the moniker in the “frameworks” section. Running your .NET Core app on the traditional .NET Framework 4.5.2

Comments
  • Thanks for you answer. Creating 2 (or more) .bat files with each their own "dotnet run x" line in it, doesn't work. Only the first will run, and the subsequent will close down immediately. I need different command line arguments for each instance.
  • one file with six occurences: This is working for me maybe you dont have Console.ReadLine(); at the end so console is closing immediately
  • With start /d "." I see that they indeed open in 2 terminals, unfortunately one of them still immediately closes :/ I guess this is the same as manually opening 2 terminals and executing the commands, but at least when you do it manually the terminal won't automatically close on it's own :/
  • I'll try to add Console.ReadLine(); at the end and see if it helps :)
  • One of them still closes, even with Console.ReadLine at the end. The App which I'm trying to start 2 instances of, is running until terminated (in this case, only one of them will be doing that, since the other one terminates). I'm surprised that this should be a problem, since I would have expected it to be a rather normal thing to do, when developing console applications with command line arguments.
  • This is the correct answer. You don't need the dll path and you can put your args on either side of --no-build.