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AppHost configuration

The AppHost project configures and starts your distributed application (DistributedApplication). When a DistributedApplication runs it reads configuration from the AppHost. Configuration is loaded from environment variables that are set on the AppHost and DistributedApplicationOptions.

Configuration includes:

  • Settings for hosting the resource service, such as the address and authentication options.
  • Settings used to start the .NET Aspire dashboard, such the dashboard's frontend and OpenTelemetry Protocol (OTLP) addresses.
  • Internal settings that .NET Aspire uses to run the AppHost. These are set internally but can be accessed by integrations that extend .NET Aspire.

AppHost configuration is provided by the AppHost launch profile. The AppHost has a launch settings file call launchSettings.json which has a list of launch profiles. Each launch profile is a collection of related options which defines how you would like dotnet to start your application.

{
  "$schema": "https://json.schemastore.org/launchsettings.json",
  "profiles": {
    "https": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "https://localhost:17134;http://localhost:15170",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development",
        "DOTNET_ENVIRONMENT": "Development",
        "ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL": "https://localhost:21030",
        "ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL": "https://localhost:22057"
      }
    }
  }
}

The preceding launch settings file:

  • Has one launch profile named https.
  • Configures an .NET Aspire AppHost project:
    • The applicationUrl property configures the dashboard launch address (ASPNETCORE_URLS).
    • Environment variables such as ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL and ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL are set on the AppHost.

For more information, see .NET Aspire and launch profiles.

Note

Configuration described on this page is for .NET Aspire AppHost project. To configure the standalone dashboard, see dashboard configuration.

Common configuration

Option Default value Description
ASPIRE_ALLOW_UNSECURED_TRANSPORT false Allows communication with the AppHost without https. ASPNETCORE_URLS (dashboard address) and ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL (AppHost resource service address) must be secured with HTTPS unless true.
ASPIRE_CONTAINER_RUNTIME docker Allows the user of alternative container runtimes for resources backed by containers. Possible values are docker (default) or podman. See Setup and tooling overview for more details.
ASPIRE_VERSION_CHECK_DISABLED false When set to true, .NET Aspire doesn't check for newer versions on startup.

Resource service

A resource service is hosted by the AppHost. The resource service is used by the dashboard to fetch information about resources which are being orchestrated by .NET Aspire.

Option Default value Description
ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL null Configures the address of the resource service hosted by the AppHost. Automatically generated with launchSettings.json to have a random port on localhost. For example, https://localhost:17037.
ASPIRE_DASHBOARD_RESOURCESERVICE_APIKEY Automatically generated 128-bit entropy token. The API key used to authenticate requests made to the AppHost's resource service. The API key is required if the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS.

Dashboard

By default, the dashboard is automatically started by the AppHost. The dashboard supports its own set of configuration, and some settings can be configured from the AppHost.

Option Default value Description
ASPNETCORE_URLS null Dashboard address. Must be https unless ASPIRE_ALLOW_UNSECURED_TRANSPORT or DistributedApplicationOptions.AllowUnsecuredTransport is true. Automatically generated with launchSettings.json to have a random port on localhost. The value in launch settings is set on the applicationUrls property.
ASPNETCORE_ENVIRONMENT Production Configures the environment the dashboard runs as. For more information, see Use multiple environments in ASP.NET Core.
ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL http://localhost:18889 if no gRPC endpoint is configured. Configures the dashboard OTLP gRPC address. Used by the dashboard to receive telemetry over OTLP. Set on resources as the OTEL_EXPORTER_OTLP_ENDPOINT env var. The OTEL_EXPORTER_OTLP_PROTOCOL env var is grpc. Automatically generated with launchSettings.json to have a random port on localhost.
ASPIRE_DASHBOARD_OTLP_HTTP_ENDPOINT_URL null Configures the dashboard OTLP HTTP address. Used by the dashboard to receive telemetry over OTLP. If only ASPIRE_DASHBOARD_OTLP_HTTP_ENDPOINT_URL is configured then it is set on resources as the OTEL_EXPORTER_OTLP_ENDPOINT env var. The OTEL_EXPORTER_OTLP_PROTOCOL env var is http/protobuf.
ASPIRE_DASHBOARD_CORS_ALLOWED_ORIGINS null Overrides the CORS allowed origins configured in the dashboard. This setting replaces the default behavior of calculating allowed origins based on resource endpoints.
ASPIRE_DASHBOARD_FRONTEND_BROWSERTOKEN Automatically generated 128-bit entropy token. Configures the frontend browser token. This is the value that must be entered to access the dashboard when the auth mode is BrowserToken. If no browser token is specified then a new token is generated each time the AppHost is launched.
ASPIRE_DASHBOARD_TELEMETRY_OPTOUT false Configures the dashboard to never send usage telemetry.
ASPIRE_DASHBOARD_AI_DISABLED false GitHub Copilot in the dashboard is available when the AppHost is launched by a supported IDE. When set to true Copilot is disabled in the dashboard and no Copilot UI is visible.

Internal

Internal settings are used by the AppHost and integrations. Internal settings aren't designed to be configured directly.

Option Default value Description
AppHost:Directory The content root if there's no project. Directory of the project where the AppHost is located. Accessible from the IDistributedApplicationBuilder.AppHostDirectory.
AppHost:Path The directory combined with the application name. The path to the AppHost. It combines the directory with the application name.
AppHost:Sha256 It is created from the AppHost name when the AppHost is in publish mode. Otherwise it is created from the AppHost path. Hex encoded hash for the current application. The hash is based on the location of the app on the current machine so it is stable between launches of the AppHost.
AppHost:OtlpApiKey Automatically generated 128-bit entropy token. The API key used to authenticate requests sent to the dashboard OTLP service. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS.
AppHost:BrowserToken Automatically generated 128-bit entropy token. The browser token used to authenticate browsing to the dashboard when it is launched by the AppHost. The browser token can be set by ASPIRE_DASHBOARD_FRONTEND_BROWSERTOKEN. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS.
AppHost:ResourceService:AuthMode ApiKey. If ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS is true then the value is Unsecured. The authentication mode used to access the resource service. The value is present if needed: the AppHost is in run mode and the dashboard isn't disabled.
AppHost:ResourceService:ApiKey Automatically generated 128-bit entropy token. The API key used to authenticate requests made to the AppHost's resource service. The API key can be set by ASPIRE_DASHBOARD_RESOURCESERVICE_APIKEY. The value is present if needed: the AppHost is in run mode, the dashboard isn't disabled, and the dashboard isn't configured to allow anonymous access with ASPIRE_DASHBOARD_UNSECURED_ALLOW_ANONYMOUS.