AWS CloudWatch Event isn't triggering

Question

I tried creating a cloudwatch event rule with the below code. However, it doesn't seem to be working. I checked AWS CloudWatch Events, and the rule is there with my attached lambda function. However, the event never gets triggered as it should. How can I fix this problem?

async function createCloudWatchEvent(zip){
    if(zip){
        try{
            await putRule(zip);
            await putTarget(zip);
        } catch (e) {
            console.log(`Can't create [${zip}] cloudwatch event`);
        }
    }
}

function putRule (ruleName) {
    let cloudWatchParams = {
      Name: ruleName, // required
      ScheduleExpression: 'rate(1 minute)',
      State: 'ENABLED'
    };

    return new Promise(resolve => {
        cloudwatchevent.putRule(cloudWatchParams, async function(err, data) {
          if(err){
            console.log(err);
            resolve(err);
          }else{
            console.log('Successfully created rule: ' + ruleName);
            resolve();
          }
        });
    });
}

function putTarget (ruleName) {
    let cloudWatchParams = {
      Rule: ruleName, // required
      Targets: [ // required
        {
          Arn: 'xxxxxxxxxx',
          Id: 'Determine_State',
          Input: JSON.stringify({zip: ruleName})
        }
      ]
    };

    return new Promise(resolve => {
        // Attach "Determine_State" target to cloudwatch event
        cloudwatchevent.putTargets(cloudWatchParams, function(err, data) {
          if(err){
            console.log(err);
            resolve(err);
          }else{
            console.log('Successfully attached target [' + cloudWatchParams.Targets[0].Id + '] to rule: ' + ruleName);
            resolve();
          }
        });
    });
}

Arun Kamalanathan · Answer 1 · 2020-01-22T05:30:18.900

0

I am not sure if you know t already, the cron schedule that you set to your lambda functions are in UTC time. For e.g, if you specify 5 pm, it is 5 pm UTC time. Maybe you are checking the logs before it executes.

Lambda permissions to log to cloudwatch

the lambda should have permission to log to cloudwatch. otherwise the lambda function will not add logs to cloudwatch. here is a policy that you can refer.

{
    "Statement": [
        {
            "Action": [
                "logs:CreateLogGroup",
                 "logs:CreateLogStream",
                 "logs:PutLogEvents"
            ],
            "Effect": "Allow",
            "Resource": "arn:aws:logs:*:*:*"
        }
    ]
}

Reference:

Can't get AWS Lambda function to log (text output) to CloudWatch

hope this helps.

edited Jan 22 '20 at 05:30

answered Jan 22 '20 at 05:25

Arun Kamalanathan

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I commented out the cron expression and changed it to 'rate(1 minute)' for testing. – Alex Feng Jan 22 '20 at 05:27
does your lambda got permission to push logs to cloudwatch – Arun Kamalanathan Jan 22 '20 at 05:30
I just did a test and works for me with the policy above. – Arun Kamalanathan Jan 22 '20 at 05:35
Once I add the permissions to my lambda's execution role, I had to redeploy the lambda for the log group to be created. good luck – Arun Kamalanathan Jan 22 '20 at 05:38
I added this policy to lambda execution role. How do I redeploy the lambda to create the log group?{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "logs:CreateLogGroup", "logs:CreateLogStream", "logs:PutLogEvents" ], "Resource": "arn:aws:logs:*:*:*" } ] } – Alex Feng Jan 22 '20 at 05:55
you can get your ci/cd to do it, for testing I have deployed from lambda console (Actions => publish new version) – Arun Kamalanathan Jan 22 '20 at 06:00
It still doesn't work. I even tried creating a new lambda function, but it didn't make a difference. I do see the log group though. – Alex Feng Jan 22 '20 at 06:08
Can you edit the cloudwatch event to see whether it shows you the next 10 occurrences of the schedule – Arun Kamalanathan Jan 22 '20 at 06:19
When I manually create the event by hand, the event rule works. However, the code doesn't work. Do you know why that might be? – Alex Feng Jan 22 '20 at 06:46
The event also only works once I manually update the event after it's been created by the code. – Alex Feng Jan 22 '20 at 07:31
sorry I dont have an answer. I suggest you raise an AWS support ticket – Arun Kamalanathan Jan 23 '20 at 07:48

score 0 · Answer 2 · answered Jan 22 '20 at 09:48

I believe you need to give permission to invoke your lambda function from the CloudWatch events (your rule). Have a look at this tutorial.

You have to either do it via CLI or from the language's AWS API. Eg:

aws lambda add-permission \
--function-name LogScheduledEvent \
--statement-id my-scheduled-event \
--action 'lambda:InvokeFunction' \
--principal events.amazonaws.com \
--source-arn arn:aws:events:us-east-1:123456789012:rule/my-scheduled-rule

AWS CloudWatch Event isn't triggering

2 Answers2

Lambda permissions to log to cloudwatch