cosmosdb-springboot-kotlin-sample

Copy of Microsoft azure cosmosdb spring data example app converted to kotlin and spring boot http api added.

Content

Small example how to use azure cosmosdb spring data SQL API (3.5.1) with spring boot (2.4.3).

Additionally presents how to use open api 3.0.3 to generate base API and model classes for spring boot rest controller.

Original article

See original article for detailed cosmos db setup information

https://docs.microsoft.com/en-us/azure/cosmos-db/create-sql-api-spring-data

Slides

Small presentation about this experiment

https://nikkijuk.github.io/cosmosdb/

Prerequisites

Kotlin
Maven
An active Azure account.
- If you don't have one, you can sign up for a free account.
Cosmos db configured
- Use sql api

App

Properties

Get keys from cosmos db accounts keys section and fill application.properties or set environment variables so that proper keys are used

application.properties

cosmos.uri=${ACCOUNT_HOST}
cosmos.key=${ACCOUNT_KEY}
cosmos.secondaryKey=${SECONDARY_ACCOUNT_KEY}

Role of application

Application loads some test data to cosmosdb

Role of controller

Controller takes requests in
Converts request parameters from api model to entities if needed
Executes database operations using injected spring data cosmosdb repository
Converts responses from entities to api model if needed
Returns response

Code for controller

  @RestController
  class SampleAppController @Autowired constructor(
  val userRepository: UserRepository
  ) : UsersApi {

      private val logger: Logger = LoggerFactory.getLogger(SampleApplication::class.java)
  
      override fun createUser(@RequestBody user: User): ResponseEntity<User> {
          val user = userRepository.save(user.toEntity())
          logger.info("saved user: $user")
          return ResponseEntity(user.toApi(), HttpStatus.OK)
      }
  
      override fun findUsers(): ResponseEntity<List<User>> {
          val users = userRepository.findAll()
          logger.info("found users: $users")
          return ResponseEntity(users.map { it.toApi() }, HttpStatus.OK)
      }
  
      override fun getUserById(@PathVariable("id") id: kotlin.String
      ): ResponseEntity<User> {
          val user = userRepository.findById(id)
          logger.info("found with id '$id' user: $user")
          return user
                  .map { ResponseEntity(it.toApi(), HttpStatus.OK) }
                  .orElse(ResponseEntity(HttpStatus.NOT_FOUND))
      }
  }