Using the SDK

Making requests

Use a service client to make requests to an AWS service. The AWS SDK for Kotlin provides Domain Specific Languages (DSLs) following a type-safe builder pattern to create requests. Nested structures of requests are also accessible through their DSLs.

The following example shows how to create an Amazon DynamoDB createTable operation input:

val ddb = DynamoDbClient.fromEnvironment()

val req = CreateTableRequest {
    tableName = name
    keySchema = listOf(
        KeySchemaElement {
            attributeName = "year"
            keyType = KeyType.Hash
        },
        KeySchemaElement {
            attributeName = "title"
            keyType = KeyType.Range
        }
    )

    attributeDefinitions = listOf(
        AttributeDefinition {
            attributeName = "year"
            attributeType = ScalarAttributeType.N
        },
        AttributeDefinition {
            attributeName = "title"
            attributeType = ScalarAttributeType.S
        }
    )
    
    // You can configure the `provisionedThroughput` member
    // by using the `ProvisionedThroughput.Builder` directly:
    provisionedThroughput {
        readCapacityUnits = 10
        writeCapacityUnits = 10
    }
}

val resp = ddb.createTable(req)

Service interface DSL overloads

Each non-streaming operation on the service client interface has a DSL overload such that you don’t even have to construct a request.

Example of creating a bucket using Amazon S3 using the overloaded function:

s3Client.createBucket {    // this: CreateBucketRequest.Builder
    bucket = newBucketName
}

This is equivalent to:

val request = CreateBucketRequest {    // this: CreateBucketRequest.Builder 
    bucket = newBucketName 
}

s3client.createBucket(request)

Requests with no required inputs

Operations that don't have required inputs can be called without having to pass a request object. This is often possible with list-type operations, such as the Amazon Simple Storage Service (Amazon S3) listBuckets API operation.

For example, the following three statements are equivalent:

s3Client.listBuckets(ListBucketsRequest {
  // Construct the request object directly.
})
s3Client.listBuckets {
  // DSL builder without explicitly setting any arguments.
}
s3Client.listBuckets()