.NET 8.0 support for API using Sqlite3 database in App_Data folder

[ganeshan]

Hi, I am using Sqlite3 database in App_Data folder. The project is a Blazor project based on .NET 8.0
x new blazor MyApp
I can use dotnet publish to create a docker image. However, when I run the app, I am getting an error that complains about not able to open database from /app/App_Data. Do I need to make changes to Dockerfile or add additional code? Is there a way to run dotnet run --AppTasks=migrate to create and populate the sqlite database?
As per one of the videos posted by ServiceStack, .NET 8.0 has build in support for Docker using dotnet publish, however, the blazor template uses Dockerfile, can you please explain why it is so? Thanks in advance

[Layoric]

The App_Data folder when running under docker is setup with GitHub Actions as somewhere your application can write to. The configured GitHub Actions also runs the dotnet run --AppTasks=migrate within the container. The GitHub actions do this via docker compose using the command docker compose up app-migration --exit-code-from app-migration.

This creates the database, and runs any outstanding migrations for your application. Locally, when you run dotnet publish, it will create the application container and push it to your local Docker repository, usually Docker Desktop. So before you run your newly created container, you want to run the AppTasks=migrate first, also ensuring that both are using the same volume mounting/pointing to the same file path on your file system.

One way you can do this is to use docker compose, you could create your own copy of the docker-compose.yml file that comes with the template, but pointing locally since that version always points to GitHub Container Registry. If you create a .env file to populate the all the options you have locally to more easily rerun.

If you create a docker-compose.yml file like below to work locally:

version: "3.9"
services:
    app:
        image: {IMAGE_NAME}
        restart: always                               
        ports:                                         
            - "8080"                                     
        container_name: ${APP_NAME}_app                
        environment:
            LC_ALL: "en_US.UTF-8"
            LANG: "en_US.UTF-8"
        volumes:
            - ./App_Data:/app/App_Data  

    app-migration:
        image: ghcr.io/${IMAGE_REPO}:${RELEASE_VERSION} 
        restart: "no"                                  
        container_name: ${APP_NAME}_app_migration       
        profiles:                                      
            - migration                                
        command: --AppTasks=migrate                     
        volumes:
            - ./App_Data:/app/App_Data                                        

Along with a .env file like:

IMAGE_NAME=<your app name, default is `myapp`>
RELEASE_VERSION=latest
APP_NAME=<your app name, default is `myapp`>

Then with the command line you can run:

docker compose up app-migration

And then run your app:

docker compose up app -d

Let us know how you go.