kohanyirobert / asp-net-core-configuration

AspNetCoreConfiguration

Sample repo to showcase how developers could use different credentials for databases or similar services when working on projects without hard-coding and committing those to their code repository.

There are two endpoints in the sample webapp

/api/config/env

At this endpoint a simple HTML snippet is display which contains information about the environment the app runs is. The value of the ConnectionStrings:Default is displayed configuration. When run in production, development mode, or during a test, or in a Docker container this can and should be different.

/api/db/test

This is an endpoint which behind the scenes connects to an existing database based on the actual value of ConnectionStrings:Default. If you run this program and you don't have an actual database running somewhere pointed to by the configuration this endpoint will throw an exception.

Steps

1. Start the production configuration and note that no configuration settings are displayed at http://localhost:5041/api/config/env
2. Start the development configuration and note that the development connection string is displayed at http://localhost:5041/api/config/env
3. Create a user secret by running dotnet user-secrets init in the project's directory (not in the solution folder) or in your IDE's built-in feature
4. Set your local connection string with the following command dotnet user-secrets set ConnectionStrings:Default "Server=local-server;Database=local-db;User Id=local-user;Password=local-password;Encrypt=False"
5. Note: the key of the setting is ConnectionStrings with an s at the end
6. Run the production config again and note that at the previous URL still the production connection string is displayed (or nothing) since user secrets are only considered in development mode
7. Run the development config and note that this time the local connection is displayed that was set in the user secrets file
8. Now stop everything and open a terminal then navigate to the project's (not the solution's) folder
9. Set the the follow environment variable
   • Using PowerShell: $Env:CONNECTIONSTRINGS__DEFAULT = "Server=prod-server;Database=prod-db;User Id=prod-user;Password=prod-password;Encrypt=False;"
   • Using Bash: export CONNECTIONSTRINGS__DEFAULT="Server=prod-server;Database=prod-db;User Id=prod-user;Password=prod-password;Encrypt=False;"
10. Finally run the application with dotnet run and note that in the previous URL the local connection string is displayed

Note: throughout these steps you can set actual, working connection strings to connect to different database servers.

Summary

1. Set public defaults into appsettings.json (e.g. like default logging level, default temp directory, etc.)
2. Set "sane" defaults into appsettings.Development.json which could serve as a sample config for newcomers to the project
3. Use dotnet user-secrets to override settings in the above files for development on your own machine
4. Override/set required settings with environment variables in different environments (production environment, Docker, GitHub Actions Workflow, AWS, etc.)
5. Never put/commit usernames, API keys, passwords, etc. into VCS

Please also check launchSettings.json, that's where it's decided whether the app runs in a production or development environment (note the "environmentVariables" section).

Recommended reading

1. https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?view=aspnetcore-8.0#hierarchical-configuration-data It's mostly interesting up until and including the section named appsettings.json and Security and user secrets
2. https://learn.microsoft.com/en-us/aspnet/core/security/app-secrets?view=aspnetcore-8.0&tabs=windows