Dapr Quick Start

Introduction to the Distributed Application Runtime

Dapr는 클라우드나 엣지에서 실행 가능하여, 간단하게 마이크로서비스 애플리케이션을 구축할 수 있게 해 준다.
분산 애플리케이션에 내재된 큰 어려움 중 하나인 복잡성을 해결해 준다.
다양한 언어를 지원한다.

 

Microservice building blocks for cloud and edge

Building Block을 제공하여 마이크로서비스 애플리케이션을 구축할 때 공통 기능에 대한 표준적인 방법을 제공한다.

 

Building Block	Endpoint	Description
Service-to-service invocation	/v1.0/invoke	Resilient service-to-service invocation enables method calls, including retries, on remote services, wherever they are located in the supported hosting environment.
State management	/v1.0/state	With state management for storing and querying key/value pairs, long-running, highly available, stateful services can be easily written alongside stateless services in your application. The state store is pluggable and examples include AWS DynamoDB, Azure Cosmos DB, Azure SQL Server, GCP Firebase, PostgreSQL or Redis, among others.
Publish and subscribe	/v1.0/publish /v1.0/subscrive	Publishing events and subscribing to topics between services enables event-driven architectures to simplify horizontal scalability and make them resilient to failure. Dapr provides at-least-once message delivery guarantee, message TTL, consumer groups and other advance features.
Resource bindings	/v1.0/bindings	Resource bindings with triggers builds further on event-driven architectures for scale and resiliency by receiving and sending events to and from any external source such as databases, queues, file systems, etc.
Actors	/v1.0/actors	A pattern for stateful and stateless objects that makes concurrency simple, with method and state encapsulation. Dapr provides many capabilities in its actor runtime, including concurrency, state, and life-cycle management for actor activation/deactivation, and timers and reminders to wake up actors.
Secrets	/v1.0/srcrets	The secrets management API integrates with public cloud and local secret stores to retrieve the secrets for use in application code.
Configuration	/v1.0/configuration	The configuration API enables you to retrieve and subscribe to application configuration items from configuration stores.
Distributed lock	/v1.0-alpha1/lock	The distributed lock API enables your application to acquire a lock for any resource that gives it exclusive access until either the lock is released by the application, or a lease timeout occurs.
Workflows	/v1.0-alpha1/workflow	The workflow API can be combined with other Dapr building blocks to define long running, persistent processes or data flows that span multiple microservices using Dapr workflows or workflow components.
Cryptography		The cryptography API provides an abstraction layer on top of security infrastructure such as key vaults. It contains APIs that allow you to perform cryptographic operations, such as encrypting and decrypting messages, without exposing keys to your applications.

 

Sidecar architecture

Dapr는 애클리케이션 코드에 Dapr 런타임 코드를 포함할 필요 없이 HTTP/gRPC API를 사이드카 아키텍처로 제공한다.

 

Hosting environments

Self-hosted local development

Dapr CLI를 사용하면 로컬 PC에서 Dapr 지원 애플리케이션을 실행 가능하다.

 

Kubernetes

Dapr는 애플리케이션에 컨테이너가 있는  동일한 Pod에 사이드카 컨테이너로 실행된다.

 

Clusters of physical or virtual machines

Dapr Control plan 서비스는 물리 또는 가상 머신에 HA모드로 구성할 수도 있다.

 

Getting started

Install Dapr CLI

설치방법 : https://docs.dapr.io/getting-started/install-dapr-cli/

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Distributed Application Runtime

Usage:
  dapr [command]

Available Commands:
  completion     Generates shell completion scripts
  components     List all Dapr components. Supported platforms: Kubernetes
  configurations List all Dapr configurations. Supported platforms: Kubernetes
  dashboard      Start Dapr dashboard. Supported platforms: Kubernetes and self-hosted
  help           Help about any command
  init           Install Dapr on supported hosting platforms. Supported platforms: Kubernetes and self-hosted
  invoke         Invoke a method on a given Dapr application. Supported platforms: Self-hosted
  list           List all Dapr instances. Supported platforms: Kubernetes and self-hosted
  logs           Get Dapr sidecar logs for an application. Supported platforms: Kubernetes
  mtls           Check if mTLS is enabled. Supported platforms: Kubernetes
  publish        Publish a pub-sub event. Supported platforms: Self-hosted
  run            Run Dapr and (optionally) your application side by side. Supported platforms: Self-hosted
  status         Show the health status of Dapr services. Supported platforms: Kubernetes
  stop           Stop Dapr instances and their associated apps. . Supported platforms: Self-hosted
  uninstall      Uninstall Dapr runtime. Supported platforms: Kubernetes and self-hosted
  upgrade        Upgrades a Dapr control plane installation in a cluster. Supported platforms: Kubernetes
  version        Print the Dapr runtime and CLI version

Flags:
  -h, --help      help for dapr
  -v, --version   version for dapr

Use "dapr [command] --help" for more information about a command.

 

Init Dapr locally

CLI를 사용해서 로컬 PC에 Dapr를 초기화한다.

• 로컬에서 Dapr 사이드카 바이너리를 가져와서 설치한다.
• Dapr로 애플리케이션 개발환경을 구축한다.

권장 개발환경은 Docker가 필요하지만 Docker 없이도 개발환경 구성은 가능하다.

참고 : https://docs.dapr.io/operations/hosting/self-hosted/self-hosted-no-docker/

 

Use the Dapr API

# Run the Dapr sidecar
$ dapr run --app-id myapp - -dapr-http-port 3500

# Save state
$ curl -X POST -H "Content-Type: application/json" -d '[f "key": "name", "value": "test"}]' http://localhost:3500/v1.0/state/statestore

# Get state
$ curl http://localhost:3500/v1.0/state/statestore/name
›› test

# See how the state is sotred in Redis
hgetall
"myapp | | name"

# Delete state
$ curl -V -X DELETE -H "Content-Type: application/json" http://localhost:3500/v1.0/state/statestore/name

 

 

Java SDK

https://docs.dapr.io/developing-applications/sdks/java/

Spring Framework과 쉽게 연동 가능하며, SDK 내부적으로는 gRPC를 사용하여 Dapr 사이드카와 통신한다.

참고

https://docs.dapr.io/concepts/overview/