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AWS Cloudformation for website uptime monitoring
Parameters:
EmailNotification:
Type: String
Description: Enter the destination email to receive the alarms.
Websiteurl:
Type: String
Description: Enter the website url.
ScheduleExpression:
Type: String
Default: "rate(5 minutes)"
Resources:
# cloudwatch alarm
uptimeAlarm:
Type: AWS::CloudWatch::Alarm
Properties:
AlarmName: !Join [ "-", [ "My-Website", !Ref Websiteurl, "is-down" ] ]
AlarmDescription: "Alarm if lambda errors out too many times"
AlarmActions: [ !Sub "arn:aws:sns:${AWS::Region}:${AWS::AccountId}:MySNSTopic" ]
Namespace: "AWS/Lambda"
MetricName: "Errors"
Dimensions:
- Name: "FunctionName"
Value: "UptimeLambdaFunction"
Statistic: "Average"
ComparisonOperator: "GreaterThanThreshold"
Threshold: 0
EvaluationPeriods: 1
Period: 300
TreatMissingData: "missing"
# sns topic
MySNSTopic:
Type: AWS::SNS::Topic
Properties:
TopicName: "MySNSTopic"
# sns subscription
MySubscription:
Type: AWS::SNS::Subscription
Properties:
Endpoint: !Ref EmailNotification
Protocol: email
TopicArn: !Ref 'MySNSTopic'
# eventRule for lambda function
ScheduledRule:
Type: AWS::Events::Rule
Properties:
Description: "ScheduledRule"
ScheduleExpression: !Ref ScheduleExpression
State: "ENABLED"
Targets:
-
Arn:
Fn::GetAtt:
- "UptimeLambdaFunction"
- "Arn"
Id: "TargetFunctionV1"
PermissionForEventsToInvokeLambda:
Type: AWS::Lambda::Permission
Properties:
FunctionName:
Ref: "UptimeLambdaFunction"
Action: "lambda:InvokeFunction"
Principal: "events.amazonaws.com"
SourceArn:
Fn::GetAtt:
- "ScheduledRule"
- "Arn"
# lambda execution role
LambdaExecutionRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Principal:
Service:
- lambda.amazonaws.com
Action:
- sts:AssumeRole
Policies:
- PolicyName: allow-logs
PolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Action:
- 'logs:*'
Resource: arn:aws:logs:*:*:*
- PolicyName: put-cw-data
PolicyDocument:
Version: '2012-10-17'
Statement:
- Effect: Allow
Action:
- 'cloudwatch:PutMetricData'
Resource: '*'
# lambda function
UptimeLambdaFunction:
Type: AWS::Lambda::Function
Properties:
FunctionName: "UptimeLambdaFunction"
Handler: "index.handler"
Runtime: nodejs10.x
Timeout: 300
Role:
Fn::GetAtt:
- "LambdaExecutionRole"
- "Arn"
Code:
ZipFile: !Sub |
'use strict';
var url = require('url');
var target = '${Websiteurl}';
exports.handler = function(event, context, callback) {
var urlObject = url.parse(target);
var mod = require(
urlObject.protocol.substring(0, urlObject.protocol.length - 1)
);
console.log('[INFO] - Checking ' + target);
var req = mod.request(urlObject, function(res) {
res.setEncoding('utf8');
res.on('data', function(chunk) {
console.log('[INFO] - Read body chunk');
});
res.on('end', function() {
console.log('[INFO] - Response end');
callback();
});
});
req.on('error', function(e) {
console.log('[ERROR] - ' + e.message);
callback(e);
});
req.end();
};
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