CloudWatch Insights — how to find context of multiple requests?

Recently I was searching through our application logs. The task was to extract extra context for a group of requests (ex. errors in the external provider system with the original request). For our app, we are using CloudWatch to store the logs. I have used CloudWatch Insights as out of the box tool to analyze them.

Our logs have a format like below, with each console output in a separate line:

2021-02-06T13:38:31.730Z info [some request id 1; some user id 1] Some external provider error message
2021-02-06T14:21:00.000Z info [some request id 2; some user id 2] Some external provider error message

We can use Cloudwatch Insights to extract all the information related to that requests:

filter @message like "Some context to error message log"
| parse @message "* * [* *] *" as timestamp,type,requestId, user, textMessage
| filter requestId in ["some request id 1;", "some request id 2"]
| sort @ingestionTime desc

If the field you are searching for is a JSON array, you can search it like:

filter @message like "Some context to error message log {
    "someInfo": [
        some1,
        some2
    ]
}"
| parse @message "* * [* *] *" as timestamp,type,requestId, user, textMessage
| parse textMessage '"someInfo":[*]' as someInfo
| filter requestId in ["some request id 1;", "some request id 2"]
| sort @ingestionTime desc

You can then export the data that you need or build some stats around it.

Let me know in the comments if you found CloudWatch Insights useful too and how you are using them.

Originally published at https://brightinventions.pl on May 5, 2021.

By Rafał Hofman, Fullstack developer @ Bright Inventions