AWS Lambda function to Slack Channel hookup

snsToSlack.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 postData = {
        "channel": "#aws-sns",
        "username": "AWS SNS via Lamda :: DevQa Cloud",
        "text": "*" + event.Records[0].Sns.Subject + "*",
        "icon_emoji": ":aws:"
    };

    var message = event.Records[0].Sns.Message;
    var severity = "good";

    var dangerMessages = [
        " but with errors",
        " to RED",
        "During an aborted deployment",
        "Failed to deploy application",
        "Failed to deploy configuration",
        "has a dependent object",
        "is not authorized to perform",
        "Pending to Degraded",
        "Stack deletion failed",
        "Unsuccessful command execution",
        "You do not have permission",
        "Your quota allows for 0 more running instance"];

    var warningMessages = [
        " aborted operation.",
        " to YELLOW",
        "Adding instance ",
        "Degraded to Info",
        "Deleting SNS topic",
        "is currently running under desired capacity",
        "Ok to Info",
        "Ok to Warning",
        "Pending Initialization",
        "Removed instance ",
        "Rollback of environment"        
        ];
    
    for(var dangerMessagesItem in dangerMessages) {
        if (message.indexOf(dangerMessages[dangerMessagesItem]) != -1) {
            severity = "danger";
            break;
        }
    }
    
    // Only check for warning messages if necessary
    if (severity == "good") {
        for(var warningMessagesItem in warningMessages) {
            if (message.indexOf(warningMessages[warningMessagesItem]) != -1) {
                severity = "warning";
                break;
            }
        }        
    }

    postData.attachments = [
        {
            "color": severity, 
            "text": message
        }
    ];

    var options = {
        method: 'POST',
        hostname: 'hooks.slack.com',
        port: 443,
        path: '/services/your-slack-webhook-url-info-goes-here'
    };

    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();
};

Thanks for this! Your newest revision removed all definitions of color, which causes the dreaded "Process exited before completing request" error.

EDIT: Actually it looks like you renamed to severity. So if you change line 65's color to severity, all is good!

Hello and thank you for this. I confirm, that line 65 was causing troubles. Replace color with severity and it should be OK.

Great , after the change of line 65 it works

Sorry for the line 65 typo. Refactor oops! I wish there were Gist notifications. If you post a response to the Medium post I can address issues faster.

Anyone have any idea of how to get it to format nicely into Slack? just comes out as a huge blob of JSON that is hardly readable :(

I had to change the request portion to:

    var payload = 'payload=' + util.format('%j', postData);
    var options = {
        method: 'POST',
        hostname: 'hooks.slack.com',
        port: 443,
        path: '/services',
        headers: {
          'Content-Type': 'application/x-www-form-urlencoded',
          'Content-Length': Buffer.byteLength(payload)
      }
    };

    var req = https.request(options, function(res) {
      res.setEncoding('utf8');
      res.on('data', function (chunk) {
        console.log(`BODY: ${chunk}`);
      });

      res.on('end', function () {
        context.done(null);
      });
    });

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

    req.write(payload);

Can anyone please help me with this script as to how to do I alert particular owners (people) in a channel where messages are posted.

Thanks in advance

@aayushKumarJarvis You can modify line 11 (text: "...") and add @channel or @here, or specific usernames.

customized this script.

• Add reaction words from Elastic Beanstalk
• Enable use mention

https://github.com/morugu/aws-lambda-function-templates/blob/master/sns/sns-to-slack.js

I guess the "message" value has changed from formatted text to json-like string recently.
I had to format the message to get human-readable text in slack:

function toText(obj) {
     var formatted = '';
     Object.keys(obj).forEach(function(key) {
       formatted += key + ': ' + obj[key] + '\n\n'
     });
     return formatted;
}

var message = event.Records[0].Sns.Message;
var messageObj = JSON.parse(message);
var message = toText(messageObj);

@makaivelli When I use your toText function the json is formatted but not all is showed. Would you be able to help with modifying it to show the full formatted json? Is there a way to select which json keys are shown and specify the title in slack message?

I'm trying to get alerts in Slack when someone login to AWS.

The JSON looks like this:

{
    "version": "x",
    "id": "x",
    "detail-type": "x",
    "source": "x",
    "account": "x",
    "time": "x",
    "region": "x",
    "resources": [],
    "detail": {
        "eventVersion": "x",
        "userIdentity": {
            "type": "x",
            "principalId": "x",
            "arn": "x",
            "accountId": "x",
            "userName": "x"
        },
        "eventTime": "x",
        "eventSource": "x",
        "eventName": "x",
        "awsRegion": "x",
        "sourceIPAddress": "x",
        "userAgent": "x",
        "requestParameters": null,
        "responseElements": {
            "ConsoleLogin": "x"
        },
        "additionalEventData": {
            "LoginTo": "x",
            "MobileVersion": "x",
            "MFAUsed": "x"
        },
        "eventID": "x",
        "eventType": "x"
    }
}

After this is parsed by toText function I only get this in Slack:

null

version: x
id: x
detail-type: x
source: x
account: x
time: x
region: x
resources:
detail: [object Object]

My knowledge of nodejs is very limited as I mostly deal with infrastructure.