.Net Core Configuration Provider that allows developers to use Google Cloud Firestore as a Configuration Source in their applications.

  public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureAppConfiguration((hostContext, config) =>
            {
              config.AddFirestoreConfiguration();
            })            
            .ConfigureWebHostDefaults(webBuilder =>
            {
              webBuilder.UseStartup<Startup>();
            });
  }

For the first time, automatically load the appsettings.json file into a Firestore Document named as the application and also a Stages collection will be created with an empty Document named as the current environment.

The provider will be listening for changes in these documents:

1. ApplicationSettings/{applicationName}
2. ApplicationSettings/{applicationName}/Stages/{stageName}
3. ApplicationSettings/{applicationName}/Stages/{stageName}/Machines/{machineName}
4. ApplicationSettings/{applicationName}/Stages/{stageName}/Tags/{tag}

When a change is made in any document, the provider reload the configuration in order from general to particular (Application -> Stage -> Machine -> Tag).

Machines and Tags collections are at stage level so when you configure both the tag configuration overrides the machine configuration.

Since the settings are loaded from Firestore into the Application Configuration they will be available through the IConfiguration interface at Startup, just like the settings declared in environment variables or appsettings.json file.