We Keep Coding

Issue WSL commands and read returned value from C#

I am writing a code to execute some commands against wsl, parsing and reading the returned value is important.
Project is a .net core console app 3.1
wsl2 is enabled on the system
for example, listing all the available wsl images on my local machine i am using a snippet found in an answer provided in another "kind of related" SO post.
using (var proc = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = #"cmd.exe",
UseShellExecute = false,
RedirectStandardOutput = true,
RedirectStandardInput = true,
CreateNoWindow = true,
}
})
{
proc.Start();
proc.StandardInput.WriteLine("wsl --list");
System.Threading.Thread.Sleep(500);
proc.StandardInput.Flush();
proc.StandardInput.Close();
proc.WaitForExit(5000);
var c = proc.StandardOutput.ReadToEnd();
Console.WriteLine(c);
Console.ReadLine();
}
now the expected output should be
what i am getting is
if i inspect using breakpoint i get this in "var c"
Ideally i want to be able to have a list that contains the 2 dockers items inside C#, changing the wait time didn't help.

in the ProcessStartInfo you have to set
StandardOutputEncoding = Encoding.Unicode;
StandardErrorEncoding = Encoding.Unicode;
for direct call of wsl use additionally:
FileName = #"wsl.exe";
Arguments = #"-l -v";

Not getting correct error code for process

I´m trying to get the return code of a batch script, which intern calls a couple other batch and exe files. When I execute the script in a CMD window and print the errorlevel, I get the correct error code, however when I do the same in C# with a process, I always get 0 as the error code.
This is my C# code
private Process ExecuteBatchFile(string batchFile)
{
Process process = new Process
{
StartInfo = new ProcessStartInfo
{
RedirectStandardOutput = false,
RedirectStandardError = false,
UseShellExecute = true,
FileName = "CMD.exe",
WorkingDirectory = Constants.ToolsPath,
Arguments = $"/c \"{batchFile} & pause\""
}
};
process.Start();
return process;
}
batchFile = $"testScript.bat -tns {Project.TnsName} & echo Error: %errorlevel%";
The output I get for the echo is Error: 0 and the process.ExitCode value is 0
If I open a CMD window and enter
cmd.exe /c "testScript.bat -tns MYTNS & echo Error: %errorlevel% & pause"
I get the correct errorlevel value.
I´m guessing it has something to do with the batch script but I don´t understand why it works in a CMD window but not in a C# Process, especially since I´m using the same method to connect a network drive and to execute an exe file.
Edit: Code without using CMD:
private Process ExecuteBatchFile(string batchFile, string args)
{
Process process = new Process
{
StartInfo = new ProcessStartInfo
{
RedirectStandardOutput = false,
RedirectStandardError = false,
UseShellExecute = true,
FileName = batchfile,
WorkingDirectory = Constants.ToolsPath,
Arguments = args
}
};
process.Start();
return process;
}
batchFile = "testScript.bat";
args = $"-tns {Project.TnsName}";

I suspect your .bat file has a line somewhere like exit /b 1. When running this .bat file from a cmd instance, the /b flag allows the .bat file to exit without closing the parent cmd process (great for running manually!).
Unfortunately, that means that when you do Process.Start("testScript.bat");, under the hood C# uses cmd to run your bat. The .bat file exits with the /b flag, signaling to the parent cmd process it shouldn't crash and therefore it exits "successfully" (exit code 0).
You have two options:
Remove the /b flag (which will correctly return the exit code .bat > cmd > process.ExitCode) - though this will mean that executing the .bat manually via a cmd instance will terminate the parent cmd upon exit
Add to your C# code to write a wrapper .bat that will pipe all args to your bat file and properly return %exitcode%:
private int ExecuteBatWithWrapper(string batFile, string args){
string runnerPath = Path.Combine(Path.GetDirectoryName(batFile), "runner.bat");
File.WriteAllText(runnerPath, $"call {batFile} %*\nexit %ERRORLEVEL%");
Process process = Process.Start(runnerPath, args); //Alternatively construct with ProcessStartInfo
File.Delete(runnerPath);
return process.ExitCode;
}
(of course, if this is used in any sort of important environment, you should incorporate that into some sort of using statement that upon disposal deletes the runner, but this is just proof-of-concept)
See https://bytes.com/topic/c-sharp/answers/511381-system-diagnostics-process-bat-file-always-returns-exit-code-0-a#post1989782 for a similar post

How to restart dotnetcore 2 C# Console app

How should I restart a dotnetcore C# console app?
I have tried suggestions found for C# console apps, but doesnt work for dotnetcore.
(This is not asp.net, which is where so many dotnetcore answers point)

OK, so im going to assume in this answer that it is ok with you if your program will start a new instance of your program and then close itself.
Here we go:
Since a dotnet console app can be started from the console, I think the best way to start a new instance of your console application would be thorugh using shell commands. To run shell commands from your program, add this helper class to your application: (If you are using windows instead of mac/linux, please see the end of this post)
using System;
using System.Diagnostics;
public static class ShellHelper
{
public static string Shell(this string cmd)
{
var escapedArgs = cmd.Replace("\"", "\\\"");
var process = new Process()
{
StartInfo = new ProcessStartInfo
{
FileName = "/bin/bash",
Arguments = $"-c \"{escapedArgs}\"",
RedirectStandardOutput = true,
UseShellExecute = false,
CreateNoWindow = true,
}
};
process.Start();
string result = process.StandardOutput.ReadToEnd();
process.WaitForExit();
return result;
}
}
Then since this is a extension method, just import it and then create a string with the command to restart your app and then use the Shell() method.
So if you are in development and you normally start your app by running dotnet run then make sure you are in the proper directory and then just use this line of code "dotnet run".Shell();
If you want to get the feedback from running the command then just assign the return value like this string result = "dotnet run".Shell();
Then once you have started the new process you just exit your current program by either returning on your main method etc.
Please Note: The above code is for mac/linux, If you are on windows, then the following two lines of the above code:
FileName = "/bin/bash",
Arguments = $"-c \"{escapedArgs}\"",
Should be replaced with:
FileName = "cmd.exe",
Arguments = $"/c \"{escapedArgs}\"",

Activating conda environment from c# code (or what is the differences between manually opening cmd and opening it from c#?)

I want to run a gpu accelerated python script on windows using conda environment (dlwin36).
I’m trying to activate dlwin36 and execute a script:
1) activate dlwin36
2) set KERAS_BACKEND=tensorflow
3) python myscript.py
If I manually open cmd on my machine and write:"activate dlwin36"
it works.
But when I try opening a cmd from c# I get:
“activate is not recognized as an internal or external command, operable program or batch file.”
I tried using the following methods:
Command chaining:
var start = new ProcessStartInfo();
start.FileName = "cmd.exe";
start.Arguments = "/c activate dlwin36&&set KERAS_BACKEND=tensorflow&&python myscript.py";
Process.Start(start).WaitForExit();
(I’ve tested several variations of UseShellExecute, LoadUserProfile and WorkingDirectory)
Redirect standard input:
var commandsList = new List<string>();
commandsList.Add("activate dlwin36");
commandsList.Add("set KERAS_BACKEND=tensorflow");
commandsList.Add("python myscript.py");
var start = new ProcessStartInfo();
start.FileName = "cmd.exe";
start.UseShellExecute = false;
start.RedirectStandardInput = true;
var proc = Process.Start(start);
commandsList.ForEach(command => proc.StandardInput.WriteLine(command));
(I’ve tested several variations of LoadUserProfile and WorkingDirectory)
In both cases, I got the same error.
It seems that there is a difference between manually opening cmd and opening it from c#.

The key is to run activate.bat in your cmd.exe before doing anything else.
// Set working directory and create process
var workingDirectory = Path.GetFullPath("Scripts");
var process = new Process
{
StartInfo = new ProcessStartInfo
{
FileName = "cmd.exe",
RedirectStandardInput = true,
UseShellExecute = false,
RedirectStandardOutput = true,
WorkingDirectory = workingDirectory
}
};
process.Start();
// Pass multiple commands to cmd.exe
using (var sw = process.StandardInput)
{
if (sw.BaseStream.CanWrite)
{
// Vital to activate Anaconda
sw.WriteLine("C:\\PathToAnaconda\\anaconda3\\Scripts\\activate.bat");
// Activate your environment
sw.WriteLine("activate your-environment");
// Any other commands you want to run
sw.WriteLine("set KERAS_BACKEND=tensorflow");
// run your script. You can also pass in arguments
sw.WriteLine("python YourScript.py");
}
}
// read multiple output lines
while (!process.StandardOutput.EndOfStream)
{
var line = process.StandardOutput.ReadLine();
Console.WriteLine(line);
}

You need to use the python.exe from your environment. For example:
Process proc = new Process();
proc.StartInfo.FileName = #"C:\path-to-Anaconda3\envs\tensorflow-gpu\python.exe";
or in your case:
start.Arguments = "/c activate dlwin36&&set KERAS_BACKEND=tensorflow&&\"path-to-Anaconda3\envs\tensorflow-gpu\python.exe\" myscript.py";

I spent a bit of time working on this and here's the only thing that works for me: run a batch file that will activate the conda environment and then issue the commands in python, like so. Let's call this run_script.bat:
call C:\Path-to-Anaconda\Scripts\activate.bat myenv
set KERAS_BACKEND=tensorflow
python YourScript.py
exit
(Note the use of the call keyword before we invoke the activate batch file.)
After that you can run it from C# more or less as shown above.
ProcessStartInfo start = new ProcessStartInfo();
start.FileName = "cmd.exe";
start.Arguments = "/K c:\\path_to_batch\\run_script.bat";
start.UseShellExecute = false;
start.RedirectStandardOutput = true;
start.RedirectStandardError = true;
start.WorkingDirectory = "c:\\path_to_batch";
string stdout, stderr;
using (Process process = Process.Start(start))
{
using (StreamReader reader = process.StandardOutput)
{
stdout = reader.ReadToEnd();
}
using (StreamReader reader = process.StandardError)
{
stderr = reader.ReadToEnd();
}
process.WaitForExit();
}
I am generating the batch file on the fly in C# to set the necessary parameters.

If this is gonna help anyone in the future. I found that you must run the activation from C:\ drive.

Unable to run python script in c# which runs scrapy spider

I followed this_link and I was able to run a dummy python file from my c# code like this...
public JsonResult FetchscrapyDataUrl(String website)
{
ProcessStartInfo start = new ProcessStartInfo();
start.FileName = #"C:\ProgramData\Anaconda3\python.exe";
start.Arguments = #"C:\Users\PycharmProjects\scraping_web\scrape_info\main.py";
//this is path to .py file from scrapy project
start.CreateNoWindow = false; // We don't need new window
start.UseShellExecute = false; // Do not use OS shell
//start.RedirectStandardOutput = true;// Any output, generated by application will be redirected back
start.RedirectStandardError = true; // Any error in standard output will be redirected back (for example exceptions)
Console.WriteLine("Python Starting");
start.RedirectStandardOutput = true;
using (Process process = Process.Start(start))
{
using (StreamReader reader = process.StandardOutput)
{
string stderr = process.StandardError.ReadToEnd(); // Here are the exceptions from our Python script
string result = reader.ReadToEnd(); // Here is the result of StdOut(for example: print "test")
Console.Write(result);
}
}
}
Now I know that I can run scrapy spider from a single file main.py like this...
from scrapy import cmdline
cmdline.execute("scrapy crawl text".split())
When I run main.py file from cmd in windows it works fine but it does not work when I run it from C# code .Net framework. The error is ...
"Scrapy 1.4.0 - no active project\r\n\r\nUnknown command: crawl\r\n\r\nUse \"scrapy\" to see available commands\r\n"
Any Idea how to run this...Or am i missing some path setting in windows ??
Or should I run my spider from C# in some other way??

You need to set the WorkingDirectory property
start.WorkingDirectory = #"C:\Users\PycharmProjects\scraping_web\scrape_info\"
Or you need to cd to that directory to make it work