Microservice APIs powered by Dapr

Azure Container Apps provides APIs powered by Distributed Application Runtime (Dapr) that help you write and implement simple, portable, resilient, and secured microservices. Dapr works together with Azure Container Apps as an abstraction layer to provide a low-maintenance and scalable platform. Azure Container Apps offers a selection of fully managed Dapr APIs, components, and features, catered specifically to microservice scenarios. Simply enable and configure Dapr as usual in your container app environment.

How the microservices APIs work with your container app

Configure microservices APIs for your container apps environment with a Dapr-enabled container app, a Dapr component configured for your solution, and a Dapr sidecar invoking communication between them. The following diagram demonstrates these core concepts, using the pub/sub API as an example.

Label	Dapr settings	Description
1	Container Apps with Dapr enabled	Dapr is enabled at the container app level by configuring a set of Dapr arguments. These values apply to all revisions of a given container app when running in multiple revisions mode.
2	Dapr	The fully managed Dapr APIs are exposed to each container app through a Dapr sidecar. The Dapr APIs can be invoked from your container app via HTTP or gRPC. The Dapr sidecar runs on HTTP port 3500 and gRPC port 50001.
3	Dapr component configuration	Dapr uses a modular design where functionality is delivered as a component. Dapr components can be shared across multiple container apps. The Dapr app identifiers provided in the scopes array dictate which dapr-enabled container apps load a given component at runtime.

Supported Dapr APIs, components, and tooling

Managed APIs

Azure Container Apps offers managed generally available Dapr APIs (building blocks). These APIs are fully managed and supported for use in production environments.

To learn more about using alpha Dapr APIs and features, see the Dapr FAQ.

API	Status	Description
Service-to-service invocation	GA	Discover services and perform reliable, direct service-to-service calls with automatic mTLS authentication and encryption. See known limitations for Dapr service invocation in Azure Container Apps.
State management	GA	Provides state management capabilities for transactions and CRUD operations.
Pub/sub	GA	Allows publisher and subscriber container apps to intercommunicate via an intermediary message broker. You can also create declarative subscriptions to a topic using an external component JSON file. Learn more about the declarative pub/sub API.
Bindings	GA	Trigger your applications based on events
Actors	GA	Dapr actors are message-driven, single-threaded, units of work designed to quickly scale. For example, in burst-heavy workload situations.
Observability	GA	Send tracing information to an Application Insights backend.
Secrets	GA	Access secrets from your application code or reference secure values in your Dapr components.
Configuration	GA	Retrieve and subscribe to application configuration items for supported configuration stores.

Compatible SDKs

Dapr's latest client SDK packages are compatible with Azure Container Apps. You can use any of the supported, GA Dapr APIs with the following Dapr client SDK versions:

Language	SDK version
Java	1.12.0
Go	1.11.0
Python	1.14.0
.NET	1.14.0
JavaScript	3.3.1
Rust	0.15.1

Tier 1 versus Tier 2 components

A subset of Dapr components is supported. Within that subset, Dapr components are broken into two support categories: Tier 1 or Tier 2.

• Tier 1 components: Stable components that receive immediate investigation in critical (security or serious regression) scenarios. Otherwise, Azure collaborates with open source to address in a hotfix or the next regular release.
• Tier 2 components: Components that are investigated on a lesser priority, as they're not in stable state or are with a third party provider.

Tier 1 components

API	Component	Type
State management	Azure Blob Storage v1 Azure Table Storage Microsoft SQL Server	state.azure.blobstorage state.azure.tablestorage state.sqlserver
Publish & subscribe	Azure Service Bus Queues Azure Service Bus Topics Azure Event Hubs	pubsub.azure.servicebus.queues pubsub.azure.servicebus.topics pubsub.azure.eventhubs
Binding	Azure Storage Queues Azure Service Bus Queues Azure Blob Storage Azure Event Hubs	bindings.azure.storagequeues bindings.azure.servicebusqueues bindings.azure.blobstorage bindings.azure.eventhubs
Secrets management	Azure Key Vault	secrets.azure.keyvault

Tier 2 components

API	Component	Type
State management	Azure Cosmos DB PostgreSQL MySQL & MariaDB Redis	state.azure.cosmosdb state.postgresql state.mysql state.redis
Publish & subscribe	Apache Kafka Redis Streams	pubsub.kafka pubsub.redis
Binding	Azure Event Grid Azure Cosmos DB Apache Kafka PostgreSQL Redis Cron	bindings.azure.eventgrid bindings.azure.cosmosdb bindings.kafka bindings.postgresql bindings.redis bindings.cron
Configuration	PostgreSQL Redis	configuration.postgresql configuration.redis

Tooling

Azure Container Apps ensures compatibility with Dapr open source tooling, such as SDKs and the CLI.

Limitations

• Dapr Configuration spec: Any capabilities that require use of the Dapr configuration spec.
• Any Dapr sidecar annotations not listed in the Dapr enablement guide
• APIs and components support: Only the Dapr APIs and components listed as GA, Tier 1, or Tier 2 in this article are supported in Azure Container Apps.
• Actor reminders: Require a minReplicas of 1+ to ensure reminders is always active and fires correctly.
• Jobs: Dapr isn't supported for jobs.

Next steps

• Enable Dapr in your container app.
• Learn how Dapr components work in Azure Container Apps.