Overview

Module that stores all log messages of your application as Mendix objects in the database, enabling you to view and search the log in the Mendix web client. Can be used in addition to the normal logging options (logging to file or the Mendix console) and has its own independent log level setting.

Documentation

Logging Module

Description

This module stores your application's log messages as Mendix objects in the database, allowing you to view and search logs directly in the Mendix web client.

It runs alongside your normal logging options (like server file or console logging) and has its own independent log level setting. It also features a scheduled event to clean up old messages, and a powerful PreFilter Rule Engine to strictly control what gets saved to the database.

Typical Usage Scenarios

• Giving application administrators access to logs directly from the Mendix interface.
• Quickly searching logs for specific errors without downloading or parsing text files.
• Filtering out noisy log messages (like specific node chatter or stack traces) before they ever reach the database to save space.

Features and Limitations

• Independent Configuration: Choose which log levels to record (e.g., INFO and higher) independently from your server's base logging.
• PreFilter Rule Engine: A flexible engine that evaluates incoming logs before they are saved. You can create rules to accept or drop messages based on regex matches against the log level, node, message text, or stack trace presence.
• Log Management: Admins can manually delete log messages.
• Automated Cleanup: The CleanupDataLogging scheduled event periodically removes old logs. Configure how many days to keep them using the LogHistoryDays constant.
• Performance Note: Writing every log to the database can slow down your app. In a production environment, we highly recommend either logging only WARNING and higher, or heavily utilizing the PreFilter engine to drop unnecessary background noise.

PreFilter Rule Engine

The PreFilter intercepts every log message right before it gets saved. It runs the message through a prioritized list of rules to decide if it should be kept or thrown away.

How Evaluation Works (First-Match-Wins)

• Rules are evaluated in order of their Priority number, from lowest (0) to highest.
• The engine checks the rule's regex pattern against your chosen log field.
• As soon as a rule matches, the engine applies the rule's Action (either keep or discard) and immediately stops evaluating the rest of the rules.
• If a log message doesn't match any active rules, the system keeps it by default.

Creating Rules When setting up a rule, you will configure the following fields:

• Action: Choose ACCEPT to keep the log or DROP to discard it.
• Target: Select which part of the log the regex should check: Level, Node, Message, or HasStackTrace.
• Regex: Write a standard Java regular expression to match the text (uses partial match logic).
• Priority: Use numbers (like 0, 1, 2) to sort the rules. Lower numbers run first.
• IsActive: A toggle to easily turn rules on or off.

Note: If a rule is marked inactive, is missing a required field, or has invalid regex syntax, the engine safely skips it without breaking your logging.

Dependencies

• Mendix 10.24 Environment
• No further dependencies

Installation & Configuration

1. Microflows: In your project settings, set your After Startup and Before Shutdown microflows to point to AfterStartup (in the Start folder) and BeforeShutdown (in the Stop folder) from the Logging module.
2. UI: Place the Message_Overview_Content snippet somewhere in your app for users to view logs.
3. Roles: Assign the Admin and/or ReadOnly module roles. Both can view logs, but only Admins can delete them.
4. Base Log Level: Set the Logging.Level constant to the desired value (defaults to INFO).
5. Automated Cleanup (Optional): Enable the Logging.CleanupDataLogging scheduled event and set the Logging.LogHistoryDays constant (defaults to -1, which means cleanup is disabled).
6. PreFilter Rules (Optional): Open the PreFilter configuration page in your Mendix app to set up your rule list. Ensure every rule you create has a valid Action, Target, and Priority.