Tag Archives: macOS

Debug an F# .NET Core app in VS Code on macOS

Press ‘F5’

The F5 button is the magic button to start debugging. However, if you start debugging the first time, you need to set up VisualStudio Code first. You need to setup a launch.json file to start debugging and a tasks.json file to first run the process.

Setup

  • Press F5
  • Select .NET Core
Initial setup for debugging: Press 'F5' and select '.NET Core'
Initial setup for debugging: Press ‘F5’ and select ‘.NET Core’
  • VS Code generates the launch.json file in the .vscode folder and opens it.
VS Code generates 'launch.json' in the '.vscode' folder
VS Code generates ‘launch.json’ in the ‘.vscode’ folder
  • Edit the launch.json file
  • Insert the configuration entry within the selected square brackets of the ‘configuration’ section
    • Press Ctrl + Space Bar
    • Select .NET: Launch .NET Core Console App
    • Enter the path to the application .dll file in the program attribute:
      "${workspaceFolder}/src/MailBoxTransformer/bin/Debug/netcoreapp3.1/MailBoxTransformer.dll"
    • The path differs from the original template because the project is within the src sub-folder.
Insert configuration entry by pressing 'Ctrl' + 'Space Bar' '.NET: Launch .NET Core Console App'
Insert configuration entry by pressing ‘Ctrl’ + ‘Space Bar’ ‘.NET: Launch .NET Core Console App’
Enter the path of the application '.dll' file in the 'program' attribute
Enter the path of the application ‘.dll’ file in the ‘program’ attribute
  • Press F5 again
  • VS Code now complains that it does not find the build task defined in the preLaunchTask attribute of the launch.json file
  • Select Configure Task
VS Code does not find the 'preLaunchTask' called 'build' and suggests to configure the task.
VS Code does not find the ‘preLaunchTask’ called ‘build’ and suggests to configure the task.
  • Select Create tasks.json file from template
Configure Task: Create 'tasks.json'
Configure Task: Create ‘tasks.json’
  • Choose the .NET Core Executes .NET core build command template
Select Task Template '.NET Core Executes .NET Core build command'
Select Task Template ‘.NET Core Executes .NET Core build command’
  • VS Code generates the tasks.json file in the .vscode folder and opens it.
  • Edit the tasks.json file
  • If the .fsproj file is not in the main folder
  • Insert the path of the directory containing the .fsproj file as an additional argument for dotnet build.
    • "${workspaceFolder}/src/MailBoxTransformer",
  • To see the logs of the build task in the console (optional):
    • Change the presentation attribute in the tasks.json file
      from "silent" to "always"
  • Press F5 again
  • VS Code runs
    • The dotnet build process
    • The app
  • Add the launch.json and the tasks.json files located in the .vscode folder to your source control system (e.g. git).
Console output of the app
Console output of the app

You are now able to start the build process and the app itself from within VS Code. Now you can set break points and debug your app. I have included the complete launch.json and the tasks.json files below. Have fun!

launch.json

  • Located in the .vscode folder
{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": ".NET Core Launch (console)",
            "type": "coreclr",
            "request": "launch",
            "preLaunchTask": "build",
            "program": "${workspaceFolder}/src/MailBoxTransformer/bin/Debug/netcoreapp3.1/MailBoxTransformer.dll",
            "args": [],
            "cwd": "${workspaceFolder}",
            "stopAtEntry": false,
            "console": "internalConsole"
        }
    ]
}

tasks.json

  • Located in the .vscode folder
{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "command": "dotnet",
            "type": "shell",
            "args": [
                "build",
                "${workspaceFolder}/src/MailBoxTransformer",
                // Ask dotnet build to generate full paths for file names.
                "/property:GenerateFullPaths=true",
                // Do not generate summary otherwise it leads to duplicate errors in Problems panel
                "/consoleloggerparameters:NoSummary"
            ],
            "group": "build",
            "presentation": {
                "reveal": "always"
            },
            "problemMatcher": "$msCompile"
        }
    ]
}

References

Create an F# .NET Core app on macOS

Create a console app with the CLI

dotnet new console -lang "F#" -o src/MyConsoleApp

Run the app in the terminal

The easy way: Move first to the folder with the .fsproj file and then use dotnet run without any arguments:

cd src/MyConsoleApp
dotnet run

If you want to start the app from a location different than the one containing the .fsproj file, you need to enter the argument --project with the path to the .fsproj file.

dotnet run --project src/MyConsoleApp/MyConsoleApp.fsproj 

References

Coding F# on macOS

Lately, I wanted to code some F# scripts. I started up Visual Studio Code on my MacBook and created an fsx file. Then I noticed that intellisense was not working anymore despite active code highlighting. That was the start for a long journey. I ended up on installing (again):

Intellisense was now working in F# projects and somehow/sometimes in fsx files within the context of an F# project. Then I tried it out in a stand-alone fsx file. Intellisense was not working again… Then I found some notes about the ‘FSharp.useSdkScripts’ option of the ionide-fsharp extension of Visual Studio Code. I activated the setting:

Visual Studio Code settings: Activate “Fsharp: Use Sdk Scripts: Use ‘dotnet fsi’ instead of ‘fsi.exe’/’fsharpi'”.

What a wonder, intellisense is working for F# fsx script files! With this setting enabled, I am no longer working with mono but with the .NET Core version of fsi (FSharp Interactive). With that, I think I don’t actually need mono.

References

Connect to a Raspberry Pi from macOS

TLDR

In the macOS Terminal preferences, uncheck ‘Set locale environment variables on startup’ in the ‘Advanced’ tab of the ‘Profiles’ section.

Issue

Weird things happen when connecting with the macOS Terminal to a Raspberry Pi. For example running the command ‘curl -fsSL get.docker.com -o get-docker.sh && sh get-docker.sh‘ for installing Docker throws errors. The script struggles because Perl has a problem with the localization. So I started digging in the dirt. When running the command ‘locale‘ to check the localization, I encountered an error message containing the phrase ‘Cannot set LC_CTYPE to default locale: No such file or directory‘.

pi@raspberrypi:~ $ locale
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE=UTF-8
LC_NUMERIC="en_GB.UTF-8"
LC_TIME="en_GB.UTF-8"
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY="en_GB.UTF-8"
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER="en_GB.UTF-8"
LC_NAME="en_GB.UTF-8"
LC_ADDRESS="en_GB.UTF-8"
LC_TELEPHONE="en_GB.UTF-8"
LC_MEASUREMENT="en_GB.UTF-8"
LC_IDENTIFICATION="en_GB.UTF-8"
LC_ALL=
pi@raspberrypi:~ $ 

or

pi@raspberrypi:~ $ locale -a
locale: Cannot set LC_CTYPE to default locale: No such file or directory
C
C.UTF-8
de_CH.utf8
en_GB.utf8
POSIX
pi@raspberrypi:~ $ 

Solution

Trying to set localization with ‘sudo raspi-config‘, ‘sudo dpkg-reconfigure locales‘ or by editing ‘/etc/locale.gen‘ and subsequently running ‘sudo locale-gen‘ did not lead to success. Finally, I found that a difference in the locale settings on the client (macOS) and the host Raspberry Pi causes conflicts and the observed issues.

Host (macOS) locale

Naiad:~ rolf$ locale
LANG=
LC_COLLATE="C"
LC_CTYPE="UTF-8"
LC_MESSAGES="C"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_ALL=

Client (Raspberry Pi) locale

pi@raspberrypi:~ $ locale
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE=UTF-8
LC_NUMERIC="en_GB.UTF-8"
LC_TIME="en_GB.UTF-8"
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY="en_GB.UTF-8"
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER="en_GB.UTF-8"
LC_NAME="en_GB.UTF-8"
LC_ADDRESS="en_GB.UTF-8"
LC_TELEPHONE="en_GB.UTF-8"
LC_MEASUREMENT="en_GB.UTF-8"
LC_IDENTIFICATION="en_GB.UTF-8"
LC_ALL=

Trick

The trick is now to not send the locale over SSH. This may be achieved by removing the ‘SendEnv LANG LC_*‘ in the ‘/etc/ssh/ssh_config‘ file.

An even easier way is to change the preferences of the macOS Terminal. To that end, uncheck ‘Set locale environment variables on startup’ in the ‘Advanced’ tab of the ‘Profiles’ section.

macOS Terminal settings: Uncheck ‘Set locale environment variables on startup’

Client (Raspberry Pi) locale after change

pi@raspberrypi:~ $ locale
LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE="en_GB.UTF-8"
LC_NUMERIC="en_GB.UTF-8"
LC_TIME="en_GB.UTF-8"
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY="en_GB.UTF-8"
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER="en_GB.UTF-8"
LC_NAME="en_GB.UTF-8"
LC_ADDRESS="en_GB.UTF-8"
LC_TELEPHONE="en_GB.UTF-8"
LC_MEASUREMENT="en_GB.UTF-8"
LC_IDENTIFICATION="en_GB.UTF-8"
LC_ALL=

References