DynamoDB
This example is composed of 3 parts:
- Provisioning DynamoDB table/GSI with CDK;
- Use high level APIs to build data access layer (DAO) for DynamoDB table;
- Provisioning lambda to use the DAO to do CRUD operations on the DynamoDB table
DynamoDB CDK
To define a DynamoDB table:
private createSnsTopicTable(tableName: string) {
const snsTopicTable = new Table(this, tableName, {
tableName: tableName,
partitionKey: {
name: 'taskId',
type: AttributeType.STRING
},
sortKey: {
name: 'userId',
type: AttributeType.STRING
},
timeToLiveAttribute: 'ttl',
billingMode: BillingMode.PAY_PER_REQUEST
});
snsTopicTable.addGlobalSecondaryIndex({
indexName: `activityByGroupIndex`,
partitionKey: {
name: "groupId",
type: AttributeType.STRING
},
sortKey: {
name: 'eventTime',
type: AttributeType.NUMBER
},
projectionType: ProjectionType.ALL
});
}
to define role and lambda to access DynamoDB table:
private createSnsTopicIngestionLambda(lambdaName: string,
lamdbaHandler: string,
snsTopicQueue: sqs.Queue,
snsTopicTable: Table) {
const snsTopicIngestionLambdaRole = new Role(this, `${lambdaName}Role`, {
roleName: `${lambdaName}IngestionRole`,
assumedBy: new ServicePrincipal('lambda.amazonaws.com'),
managedPolicies: [ManagedPolicy.fromAwsManagedPolicyName('service-role/AWSLambdaBasicExecutionRole')],
inlinePolicies: {
'SnsTopicQueueAccessPolicy': new PolicyDocument({
statements: [
new PolicyStatement({
actions: ['sqs:receieveMessage'],
effect: Effect.ALLOW,
resources: [snsTopicQueue.queueArn]
})
]
}),
'SnsTopicTableAccessPolicy': new PolicyDocument({
statements: [
new PolicyStatement({
actions: [
'dynamodb:ConditionCheckItem',
'dynamodb:PutItem',
'dynamodb:UpdateItem',
'dynamodb:DeleteItem',
'dynamodb:GetItem'
],
effect: Effect.ALLOW,
resources: [snsTopicTable.tableArn]
})
]
})
}
});
const snsTopicIngestionLambda = new Function(this, lambdaName, {
functionName: lambdaName,
runtime: Runtime.JAVA_8,
handler: lamdbaHandler,
code: lambda.Code.asset("path/to/artifact"),
timeout: Duration.seconds(30),
memorySize: 256,
role: snsTopicIngestionLambdaRole,
events: [new SqsEventSource(snsTopicQueue, { batchSize: 10 })],
environment: {
'SNS_TOPIC_TABLE': snsTopicTable.tableName
}
});
return snsTopicIngestionLambda;
}
DynamoDB Data Access
Here is an overview of DynamoDB APIs:
