helloworldless / aws-cheatsheet

Cheatsheet for all things AWS

AWS Cheatsheet

Cheatsheet for all things AWS

Basic

1. SDKs paramters are case sensitive

DynamoDB

1. Beware of discrepancies between SDKs and documents, for example, put vs. putItem
2. Primary Key is referred to as the HASH
3. Sort key is referred to as the RANGE
4. DynamoDB is schemaless, so at table creation time, you only need to define the HASH parameter and optionally the RANGE parameter

// TODO - add notes about unique constraints across HASH and RANGE

Example

Create Table (Serverless Framework)

Type: AWS::DynamoDB::Table
Properties:
  TableName: ${self:custom.dynamoTableName}
  AttributeDefinitions:
    - AttributeName: userId
      AttributeType: S
    - AttributeName: createdAt
      AttributeType: S
  KeySchema:
    - AttributeName: userId
      KeyType: HASH
    - AttributeName: createdAt
      KeyType: RANGE
  ProvisionedThroughput:
    ReadCapacityUnits: 1
    WriteCapacityUnits: 1

Initialize JavaScript SDK

const AWS = require('aws-sdk');
AWS.config.update({ region: 'us-east-1' });
const dynamo = new AWS.DynamoDB.DocumentClient();

Query Operation

const params = {
    TableName: 'notes',
    KeyConditionExpression: 'userId = :userId',
    ExpressionAttributeValues: {
        ':userId': '037f49db-c102-4f02-b7f1-99b254655171',
    },
};
const result = await dynamo.query(params).promise();

API Gateway

1. REST API is the most common
2. To integrate with a Lambda, there are two types:
3. LAMBDA_PROXY 1. A lot of documentation assumes you're using this if you're routing to a Lambda 1. Gives up some control in favor of ease of use and conventions like indicating statusCode via the returned object: {statusCode: 500, body: 'Internal Server Error'}
4. LAMBDA 1. Gives the most control, allows some logic to be built into the API Gateway rather than in client code, for example

Lambda

Example LAMBDA_PROXY Event

Click to expand

{
    "resource": "/activities",
    "path": "/activities",
    "httpMethod": "POST",
    "headers": {
        "Accept": "*/*",
        "Accept-Encoding": "gzip, deflate, br",
        "Authorization": "<REMOVED>",
        "Cache-Control": "no-cache",
        "CloudFront-Forwarded-Proto": "https",
        "CloudFront-Is-Desktop-Viewer": "true",
        "CloudFront-Is-Mobile-Viewer": "false",
        "CloudFront-Is-SmartTV-Viewer": "false",
        "CloudFront-Is-Tablet-Viewer": "false",
        "CloudFront-Viewer-Country": "US",
        "Content-Type": "text/plain",
        "Host": "<REMOVED>.execute-api.us-east-1.amazonaws.com",
        "Postman-Token": "<REMOVED>",
        "User-Agent": "PostmanRuntime/7.25.0",
        "Via": "1.1 ede80d7a8b8f3860f5bfc65271bbce47.cloudfront.net (CloudFront)",
        "X-Amz-Cf-Id": "<REMOVED>",
        "X-Amzn-Trace-Id": "<REMOVED>",
        "X-Forwarded-For": "<REMOVED>",
        "X-Forwarded-Port": "443",
        "X-Forwarded-Proto": "https"
    },
    "multiValueHeaders": {
        "Accept": [
            "*/*"
        ],
        "Accept-Encoding": [
            "gzip, deflate, br"
        ],
        "Authorization": [
            "<REMOVED>"
        ],
        "Cache-Control": [
            "no-cache"
        ],
        "CloudFront-Forwarded-Proto": [
            "https"
        ],
        "CloudFront-Is-Desktop-Viewer": [
            "true"
        ],
        "CloudFront-Is-Mobile-Viewer": [
            "false"
        ],
        "CloudFront-Is-SmartTV-Viewer": [
            "false"
        ],
        "CloudFront-Is-Tablet-Viewer": [
            "false"
        ],
        "CloudFront-Viewer-Country": [
            "US"
        ],
        "Content-Type": [
            "text/plain"
        ],
        "Host": [
            "<REMOVED>.execute-api.us-east-1.amazonaws.com"
        ],
        "Postman-Token": [
            "<REMOVED>"
        ],
        "User-Agent": [
            "PostmanRuntime/7.25.0"
        ],
        "Via": [
            "<REMOVED>"
        ],
        "X-Amz-Cf-Id": [
            "<REMOVED>"
        ],
        "X-Amzn-Trace-Id": [
            "<REMOVED>"
        ],
        "X-Forwarded-For": [
            "<REMOVED>"
        ],
        "X-Forwarded-Port": [
            "443"
        ],
        "X-Forwarded-Proto": [
            "https"
        ]
    },
    "queryStringParameters": null,
    "multiValueQueryStringParameters": null,
    "pathParameters": null,
    "stageVariables": null,
    "requestContext": {
        "resourceId": "ohbrd5",
        "authorizer": {
            "claims": {
                "at_hash": "<REMOVED>",
                "sub": "<REMOVED>",
                "aud": "<REMOVED>",
                "email_verified": "true",
                "event_id": "<REMOVED>",
                "token_use": "id",
                "auth_time": "1592265376",
                "iss": "https://cognito-idp.us-east-1.amazonaws.com/<REMOVED>",
                "cognito:username": "<REMOVED>",
                "exp": "Tue Jun 16 00:56:16 UTC 2020",
                "iat": "Mon Jun 15 23:56:16 UTC 2020",
                "email": "<REMOVED>"
            }
        },
        "resourcePath": "/activities",
        "httpMethod": "POST",
        "extendedRequestId": "<REMOVED>",
        "requestTime": "16/Jun/2020:00:30:22 +0000",
        "path": "/dev/activities",
        "accountId": "<REMOVED>",
        "protocol": "HTTP/1.1",
        "stage": "dev",
        "domainPrefix": "<REMOVED>",
        "requestTimeEpoch": 1592267422277,
        "requestId": "<REMOVED>",
        "identity": {
            "cognitoIdentityPoolId": null,
            "accountId": null,
            "cognitoIdentityId": null,
            "caller": null,
            "sourceIp": "<REMOVED>",
            "principalOrgId": null,
            "accessKey": null,
            "cognitoAuthenticationType": null,
            "cognitoAuthenticationProvider": null,
            "userArn": null,
            "userAgent": "PostmanRuntime/7.25.0",
            "user": null
        },
        "domainName": "<REMOVED>.execute-api.us-east-1.amazonaws.com",
        "apiId": "<REMOVED>"
    },
    "body": "{\r\n    \"createdAt\": \"2020-06-15T23:56:39.724Z\",\r\n    \"type\": \"EAT\"\r\n}",
    "isBase64Encoded": false
}

Example LAMBDA Integration Request Mapping

Uses DSL to construct even which is sent to the Lambda

Where this lives: Resources > Choose Resource > Integration Request

Mapping Templates > Select a Content Type

#set($inputRoot = $input.path('$'))
{
  "operation": "put",
  "params": {
      "TableName" : "notes",
      "Item" : {
          "userId" : "$context.authorizer.claims.sub",
          "noteId" : "$inputRoot.noteId",
          "note" : "$inputRoot.note"
       }
  }
}