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I Made a Viewer for cognosserver.log Files

December 11, 2020 by Steven Ng

I had to go through a cognosserver.log file recently, and boy was it painful.

There is so much work to separate the wheat from the chaff, and looking at the log file even in a good text editor can make any person's head explode.

I've made a static web application (here: that lets you either load a cognosserver.log file, or paste a snippet from a log file into it.

Once you've loaded the log in, it shows you a cleaner view of the log file, and you can filter by keyword, or flag log entries to make filtering even easier.

Note that this app only reads cognosserver.log files. At some point I may make a separate app that reads audit logs, but I was focused at solving the pain point I had at the moment.

In terms of data storage, none of the log files you load are stored on any server. I use the browser's built in data store (works similar to a cookie), and I've provided a mechanism for you to wipe the database.

In terms of performance, since everything is running in a browser, the bigger the file, the slower it will be to load and process. Also, I've only tested it with Cognos 11.1.x logs. No guarantees it will work on older logs.

This app wasn't written to be sold or anything, so I only did a minimal amount of testing and trapping. Keep the old adage of "garbage in, garbage out" in mind when using it.

You can report issues here: but there's no guarantee I'll address them, as this was only designed for my specific needs and not be some huge do-it-all application.