LambdaToNannyCheckinCheckout

gistfile1.txt

/**
 * This is a sample Lambda function that records nanny check in/out activities
 * in DynamoDB and sends SMS messages to the phone number on file.
 * 
 * This function creates a DynamoDB table 'button_nanny_checkin' the first time
 * it runs. The table uses button's DSN as hash key and timestamp as range key.
 * Each entry has an activity message.
 * 
 * If phone number is set, an SMS message about this check in/out activity will
 * be sent.
 * 
 * Permissions required for this function to run are the following:
{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt1472255738000",
            "Effect": "Allow",
            "Action": [
                "dynamodb:CreateTable",
                "dynamodb:DescribeTable",
                "dynamodb:PutItem",
                "dynamodb:Query"
            ],
            "Resource": [
                "arn:aws:dynamodb:*:*:table/button_nanny_checkin"
            ]
        },
        {
            "Sid": "Stmt1472255738001",
            "Effect": "Allow",
            "Action": [
                "sns:Publish"
            ],
            "Resource": [
                "*"
            ]
        }
    ]
}
 */

const AWS = require('aws-sdk');
const SNS = new AWS.SNS({ apiVersion: '2010-03-31' });
const dynamodb = new AWS.DynamoDB();

const TABLE_NAME = "button_nanny_checkin"; // DynamoDB table name
const PHONE_NUMBER = null; // config your phone number for SMS or null

function getButtonAttributes(event, callback) {
    Iot.describeThing({ thingName: 'IotButton_' + event.serialNumber }, callback);
}

function sendSMS(event, phoneNumber, callback) {
    if (phoneNumber !== null) {
        console.log(`Sending SMS to ${phoneNumber}`);
        const params = {
            PhoneNumber: phoneNumber,
            Message: getMessage(event)
        };
        // result will go to function callback
        SNS.publish(params, callback);
    } else {
        callback(null);
    }
}

/**
 * Checks whether the table exists and is active by calling DescribeTable.
 */
function createTableIfNeeded(tableName, callback) {
    dynamodb.describeTable({ TableName: tableName }, (err, data) => {
        if (err) {
            if (err.code === 'ResourceNotFoundException') {
                createTable(tableName, (err, data) => {
                    if (err) {
                        callback(err);
                    } else {
                        callback('Table has been created but is not ready.');
                    }
                });
            } else {
                callback(err);
            }
        } else {
            // table already created
            if (data.Table.TableStatus !== "ACTIVE") {
                callback(`Table ${tableName} is not ready with status ${data.Table.TableStatus}.`);
            } else {
                callback(null, data);
            }
        }
    });
}

/**
 * The table uses button's DSN as hash key and timestamp as range key.
 * Each entry has an activity message.
 */
function createTable(tableName, callback) {
    const param = {
        TableName: tableName,
        KeySchema: [
            { AttributeName: "dsn", KeyType: "HASH" },
            { AttributeName: "timestamp", KeyType: "RANGE" }
        ],
        AttributeDefinitions: [
            { AttributeName: "dsn", AttributeType: "S" },
            { AttributeName: "timestamp", AttributeType: "N" }
        ],
        ProvisionedThroughput: {       
            ReadCapacityUnits: 10, 
            WriteCapacityUnits: 5
        }
    };
    dynamodb.createTable(param, callback);
}

/**
 * Saves nanny check in/out activity into DynamoDB
 */
function saveEvent(event, callback) {
    const params = {
        TableName: TABLE_NAME,
        Item: {
            dsn: { S: event.serialNumber },
            timestamp: { N: new Date().getTime().toString() },
            message: { S: getMessage(event) }
        }
    };
    dynamodb.putItem(params, callback);
}

/**
 * The following JSON template shows what is sent as the payload:
{
    "serialNumber": "GXXXXXXXXXXXXXXXXX",
    "batteryVoltage": "xxmV",
    "clickType": "SINGLE" | "DOUBLE" | "LONG"
}
 *
 * A "LONG" clickType is sent if the first press lasts longer than 1.5 seconds.
 * "SINGLE" and "DOUBLE" clickType payloads are sent for short clicks.
 *
 * For more documentation, follow the link below.
 * http://docs.aws.amazon.com/iot/latest/developerguide/iot-lambda-rule.html
 */

function getMessage(event) {
    if (event.clickType === 'SINGLE') {
        return 'Your nanny checked in.';
    }
    if (event.clickType === 'DOUBLE') {
        return 'Your nanny checked out.';
    }
    if (event.clickType === 'LONG') {
        return 'Your nanny needs help!';
    }
    return 'Unknown event: ' + event.clickType;
}


exports.handler = (event, context, callback) => {
    console.log('Received event:', event.clickType);

    // checks whether the table is ready
    createTableIfNeeded(TABLE_NAME, (err, data) => {
        if (err) {
            console.log("Something wrong with table: " + TABLE_NAME, err);
            context.done("Failed to access DynamoDB table.");
            return;
        }
        // writes event into Dynamo
        saveEvent(event, (err, data) => {
            if (err) {
                console.log("Failed to save event: " + JSON.stringify(event), err);
                context.done("Failed to save event.");
            } else {
                console.log("Successfully recorded event.");
                // and sends an SMS message if configured
                sendSMS(event, PHONE_NUMBER, (err, data) => {
                    if (err) {
                        console.log("Failed to send SMS");
                        context.done(err);
                    } else {
                        context.done(null, event);
                    }
                });
            }
        });
    });
};