How to push the correct configuration data with C# worker service to swarm/kubernetes?

I have 3 configs in service:

1 - appsettings.development.json
2 - appsettings.testing.json
3 - appsettings.production.json

And i have 3 launch settings for them as well in launchsettings.json:

{
    "profiles": {
        "DevelopmentDockerProfile" {
            "commandName": "Docker",
            "environmentVariables": {
                "DOTNET_ENVIRONMENT": "development"
            }
        },
        "ProductionDockerProfile" {
            "commandName": "Docker",
            "environmentVariables": {
                "DOTNET_ENVIRONMENT": "production"
            }
        },
        "TestingDockerProfile" {
            "commandName": "Docker",
            "environmentVariables": {
                "DOTNET_ENVIRONMENT": "testing"
            }
        }
    }
}

And i can normally run service, using correct configuration only on local machine.

I can not push DOTNET_ENVIRONMENT variable with service when publishing.

Is there any way to bind environment variable to publishProfile.pubxml or whatever else, that environment variable DOTNET_ENVIRONMENT will magically appear in docker service on host machine?

Solution

Short answer

No, there is no such option.

Longer one

First of all, you can easily set environment variables using Environment.SetEnvironmentVariable("name", "value"). But that's probably not what you want.

What you might want is to configure environment variables in configs for container/orchestration tool you use, either set in docker command line (docker run -e VARIABLE_NAME=value) or in docker-compose.yml for Docker Compose or in service YAML config for k8s.