Logging

🕓 10 minutes

What you’ll learn

How to use logs of your application for monitoring, debugging, and better understanding of the process behind the code.

Logging helps you to:

• Follow the system actions and information about user.
• Reveal application problems together with the place where they occur.

Prerequisites

• Create a New Application
• Create a New Application Component
• Build your application
• Deploy your Application

Loki

CodeNow is using Grafana Loki for logs, which is a horizontally scalable log aggregation system.

• Loki comes with its own language for queries called LogQL.
• LogQL uses labels and operators for filtering.

How to find a log

1. In Logging & Tracing section of the sidebar, select Logging.
2. In order to generate a query, you need to set label filter expressions. That means choosing a label and attaching a certain value and operation to it.
   • In Loki, a label can represent the namespace, application, pod, etc.
   • Remember that you can't use a traceID for application logs.
   • You can attach multiple label filter expressions to a single query.
3. If you prefer entering a query manually, you can switch by clicking on the Code button.
4. If you get lost while generating queries, there is a Loki Cheat Sheet (❓ button) to help you with making queries.
   • For a better understanding of Loki's query language, please refer to Loki's documentation.
5. Once you have generated a query, run it by clicking on the Run query button.
6. Now you can see the results of your query, specifically:
   • Log statistics in time
   • Application logs
     • You can adjust the appearance with a menu on top of the logs.
7. Find the log you were looking for and click on it for more details.

Navigate to logging

Set labels

Switch to code mode

Loki Cheat Sheet

Run a query

View the results of your query

Expand log for further information

1 / 7

Additional settings

Time

• Set the time range on which your query will run by clicking the 🕓 button
• For live logging, click on the Live button. You can pause or stop the live monitoring by clicking on the Live button again.

Using More Queries

1. Add a new Query by clicking on the Add query button
2. You can do the following operations with queries:
   • Duplicate a query - creates a new query with the same settings as the selected one
   • Disable/enable query - query won't/will run when Run query is pressed
   • Remove query - removes the selected query
   • Drag and drop to reorder

Add a new query

Query operations

1 / 2

tip

Learn more about Loki