Adding CloudWatchEvents to AWS lambda function

Question

I have 2 AWS lambda functions belonging to the same account producer and consumer function. I want the producer to schedule the consumer to run at a specified time. When I check under CloudWatch Events the events are being created but the consumer is not being triggered. I am using this link

Producer Code

var AWS = require('aws-sdk');

var cwevents = new AWS.CloudWatchEvents({apiVersion: '2015-10-07'});

var params_for_rule = {
  Name: 'DEMO_EVENT',
  ScheduleExpression: 'cron(0/3 * * * ? *)',
  State: 'ENABLED'  
};

var params_for_target = {
  Rule: 'DEMO_EVENT',
  Targets: [
    {
      Arn: 'consumer',
      Id: 'default',
    }
  ]
};

exports.handler = async (event, context, callback) => {

  const response = {
    statusCode: 200,
    body: JSON.stringify('Hello from Lambda!'),
  };

  cwevents.putRule(params_for_rule, function(err, data){
    if(err){
      console.log("Not Working");
    }
    else{
      console.log("Working");
      cwevents.putTargets(params_for_target, function(err, data){
        if(err){
          console.log("Not Working");
        }
        else{
          console.log("Working");
        }
      });
    }
  });
};

Answer 1

You are calling callback before the function putTargets will return.
Your callback code should be done after putTargets returns with success.

cwevents.putRule(params_for_rule, function(err, data){
    if(err){
      console.log("Not Working");
    }
    else{
      console.log("Working");
      cwevents.putTargets(params_for_target, function(err, data){
        if(err){
          console.log("Not Working");
          callback(err, null);
        }
        else{
          console.log("Working");
          callback(null, response);
        }
      });
    }
  });

Answer 2

For the cloud Watch event to be added we need to add certain permissions using the addPermission method. Here is the document.

Here is the sample code.

cwevents.putRule(params_for_rule, function(err, data){
    if(err){
      console.log("Not Working",data);
    }
    else{
      console.log("Working",data);
      lambda.addPermission(lambdaPermission, function(err, data){
        if(err){
          console.log(err);
        }
        else{
          console.log(data);
          cwevents.putTargets(params_for_target, function(err, data){
            if(err){
              console.log("Not Working",data);
            }
            else{
              console.log("Working",data);
            }
          });
        }
      }); 
    }
  });