CODEWITHSUNDEEP
amazon-web-servicesgrepamazon-cloudwatch
Costa Michailidis
Costa Michailidis

Reputation: 8178

How to filter AWS logs for Lambda to see just console.logs

I'm currently using aws logs filter-log-events --log-group-name /aws/lambda/lambda-name --region us-east-1 to get logs from a lambda, but the logs that come back are quite.... extensive. For example:

{
  "ingestionTime": *, 
  "timestamp": *, 
  "message": "START RequestId: * Version: $LATEST\n", 
  "eventId": "*", 
  "logStreamName": "2018/10/26/[$LATEST]*"
}...

Can I get just the messages out with only a bash command that fits in the npm script? Maybe with grep or find.

Upvotes: 2

Views: 1749

Answers (1)

jmp
jmp

Reputation: 2375

To get the specific attributes in the logs returned by the filter-log-events command you can use jq. Here is an example that I did in windows powershell.

aws logs filter-log-events --log-group-name <yourLogGroup> --region <yourRegion> | jq '.events[].message'

There is also a --filter-pattern parameter which there are some examples for here

If the command needs to get the last few days it can use the --start-time and --end-time parameters of the filter-log-events command.

To have a real time subscription of the CloudWatch logs, the project can use the put-subscription-filter command to write the logs to another Lambda function to process them. Here is an example function in nodejs:

https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/SubscriptionFilters.html#LambdaFunctionExample

var zlib = require('zlib');
exports.handler = function(input, context) {
    var payload = new Buffer(input.awslogs.data, 'base64');
    zlib.gunzip(payload, function(e, result) {
        if (e) { 
            context.fail(e);
        } else {
            result = JSON.parse(result.toString('ascii'));
            console.log("Event Data:", JSON.stringify(result, null, 2));
            context.succeed();
        }
    });
};

Upvotes: 3

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