CodeDeploy notifications to Slack (AWS Lambda via SNS)

codedeploy-to-slack.js

var https = require('https');
var util = require('util');

exports.handler = function (event, context) {
    console.log(JSON.stringify(event, null, 2));
    console.log('From SNS:', event.Records[0].Sns.Message);

    var severity = "good";
    var message = event.Records[0].Sns.Message;
    var messageJSON = JSON.parse(message);
    var subject = event.Records[0].Sns.Subject;

    var postData = {
        channel: "#channel",
        username: "CodeDeploy",
        icon_emoji: ":codedeploy:"
    };

    if (messageJSON.status == "FAILED") {
        severity = "danger"
    }
    if (messageJSON.status == "STOPPED") {
        severity = "warning"
    }

    var fields = [];
    for (var key in messageJSON) {
        if (key == 'deploymentOverview') {
            var value = [];
            var deploymentOverview = JSON.parse(messageJSON[key]);
            for (var status in deploymentOverview) {
                value.push(status + ': ' + deploymentOverview[status]);
            }
            fields.push({
                "title": key
                    .replace(/([A-Z])/g, ' $1')
                    .replace(/^./, function (str) {
                        return str.toUpperCase();
                    }),
                "value": value.join(', '),
            });
        } else {
            fields.push({
                "title": key
                    .replace(/([A-Z])/g, ' $1')
                    .replace(/^./, function (str) {
                        return str.toUpperCase();
                    }),
                "value": messageJSON[key],
                "short": true
            });
        }
    }

    postData.attachments = [
        {
            "color": severity,
            "fallback": message,
            "title": subject,
            "title_link": "https://console.aws.amazon.com/codedeploy/home?region=" + messageJSON.region + "#/deployments/" + messageJSON.deploymentId,
            "fields": fields
        }
    ];

    var options = {
        method: 'POST',
        hostname: 'hooks.slack.com',
        port: 443,
        path: '/services/yourservicehookhere'
    };

    var req = https.request(options, function (res) {
        res.setEncoding('utf8');
        res.on('data', function (chunk) {
            context.done(null);
        });
    });

    req.on('error', function (e) {
        console.log('problem with request: ' + e.message);
    });

    req.write(util.format("%j", postData));
    req.end();
};

error

{
"errorType": "SyntaxError",
"errorMessage": "Unexpected token e in JSON at position 0",
"trace": [
"SyntaxError: Unexpected token e in JSON at position 0",
" at JSON.parse ()",
" at Runtime.exports.handler (/var/task/index.js:10:28)",
" at Runtime.handleOnce (/var/runtime/Runtime.js:66:25)"
]
}