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Open the Aspire glossary, or follow a definition below.
Core concepts
- AppHost
The executable application model that declares your services, resources, connections, and local orchestration.
- Distributed application
An application whose parts communicate across process or network boundaries, rather than running as a single unit.
- Polyglot
Describes an application or toolchain that uses multiple programming languages, with Aspire coordinating its resources.
- Resource
A building block in the Aspire application model, such as a service, container, executable, cloud resource, or parameter.
- Service defaults
Shared .NET application setup for telemetry, health checks, service discovery, and HTTP resilience that you explicitly opt into.
APIs and patterns
- WaitFor
Delays a resource's startup until a dependency is running and its configured health checks pass.
- WaitForCompletion
Delays startup until a dependency exits with the expected exit code, rather than only waiting for it to run.
- WaitForStart
Delays startup until a dependency reaches the running state, without waiting for its health checks.
- WithReference
Supplies a consuming resource with connection strings or service endpoint configuration from another resource.
Key terms
- Connection string
A formatted value containing the address and options a client needs to connect to a database, cache, or similar service.
- Environment variable
A process-level name and value used to pass configuration, endpoints, and connection information to an application.
- Health check
A probe that reports whether a service or dependency is functioning, with separate roles for orchestration and application endpoints.
- Service discovery
Resolves logical service names to configured endpoints so clients do not need hard-coded network addresses.
Resource types
- Client integration
An integration used inside an application to configure a service client, often with dependency injection, health checks, and telemetry.
- Hosting and client relationship
The division between modeling a dependency in the AppHost and connecting to that dependency inside an application.
- Hosting integration
An Aspire integration that adds and configures resources in the AppHost application model.
Execution modes
- Publish mode
The AppHost execution mode that produces deployment artifacts from the application model using configured deployment integrations.
- Run mode
The AppHost execution mode used to orchestrate an application's resources during local development.
Dashboard and observability
- Aspire dashboard
A web interface for exploring resource status, console output, structured logs, distributed traces, and metrics.
- OpenTelemetry
A standard and ecosystem for collecting and exporting logs, traces, and metrics from instrumented applications.
Common patterns
- Emulator pattern
Replaces a supported cloud resource with a local emulator for development while keeping the resource in the application model.
- Existing resource pattern
Connects an application to a dependency that already exists instead of creating and managing a new instance.
API reference terms
- DAG
A directed acyclic graph: nodes connected by directional edges, with no path that loops back to its starting node.
- Deferred evaluation
Resolving or computing a value only when the information needed to produce it is available.
- Heterogeneous DAG
A dependency graph containing different kinds of nodes, such as application projects, containers, cloud resources, and parameters.
- Hoisting
In resource publishing, preserving an unresolved value for substitution at a later deployment or runtime stage.
- IResourceAnnotation
The .NET interface for typed metadata attached to an Aspire resource to describe configuration or behavior.
- Lifecycle events
Signals emitted at application or resource lifecycle stages so handlers can participate in orchestration.
- Publisher
A component that interprets the application model and emits deployment artifacts for a particular target or format.
- ReferenceExpression
A structured expression that combines text and resource value references without resolving those references too early.
- ResourceNotificationService
An AppHost service that publishes resource state snapshots for observers such as the dashboard and orchestration.
- WithAnnotation
A C# resource-builder extension method that attaches typed annotation metadata to a resource.