MQL5 Log Handlers: Per-Handler Formatters, Caching, and File Rotation

Summary

This installment in a logging-library series describes changes intended to make file logging more flexible and efficient. It moves formatting responsibility from a single shared formatter to each handler, allowing destinations such as a console and a file to use different output formats. The article then develops file-handler improvements centered on caching log records before writing and rotating files, with the aim of reducing frequent disk operations and managing log-file growth.

The material is implementation-focused: it discusses the handler architecture, formatter ownership, and related MQL5 code, with a test program serving as a practical example. It also situates these features within a larger library that supports log levels and multiple destinations. The article does not establish quantified performance gains or evaluate trading performance; the described techniques improve EA diagnostics and maintenance rather than provide a market signal.

Key ideas

• Giving each log handler its own formatter allows output formats to differ by destination.
• Caching batches log records before file writes to reduce repeated write operations.
• File rotation provides a way to manage the growth of persistent logs.
• Logging infrastructure helps developers inspect and maintain Expert Advisors but does not itself create a trading edge.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.