Snippets code from my daily experience

July 28, 2008

Komodo logging facilities

Filed under: extension,komodo,xul — dafi @ 7:04 pm

Any programmer needs an easy way to log messages to trace bugs or to simplify problem diagnostic.

Mozilla extensions developers have two way to log messages; the dump function and the nsIConsoleService interface, both are invaluable developer friends.

Who lands on Komodo extension development finds a very rich set of methods to make log, so rich the dump and nsIConsoleService lose their value.

The namespace ko.logging wraps the koILoggingService methods and more over.

The code shown below print a warning and an error message


The getLogger works like a singleton, it uses a map to store requested loggers, this minimize the memory allocated reusing already-instantiated logger objects.

I use the practice to pass a string in “” form. This naming technique simplify searching into log and splits komodo from thirdy parts (extensions) log messages.

There are two important caveats:

  • How to use ko.logging namespace
  • Where output goes

How to use ko.logging namespace

ko.logging is available to all elements overlaying komodo.xul (menus, tab panels, and  so on) but if you need it inside your xul dialog you need to use a ugly syntax like opener.ko.logging or opener.opener.ko.logging (when you call from a dialog open from a parent dialog).

Lucky a better solution consists to include javascript files and use the clean ko.logging syntax.

Add the line shown below to your xul dialog and all will work fine

<script type=”application/x-javascript” src=”chrome://komodo/content/library/logging.js” />

Where output goes

Output is visible when you start komodo with the verbose flag.

I use the script shown below in my Ubuntu box to always log messages, the script deletes the komodo.log file when its size is greater than 500000 bytes.

CURR_SIZE=` ls -l ~/komodo.log | awk ‘{print $5}’`
if [ $CURR_SIZE -gt 500000 ];
rm ~/komodo.log

/opt/devel/mozilla/Komodo-Edit-4/bin/komodo 2>>~/komodo.log -v

Under Windows Komodo opens an annoyng dos window where output is displayed and I was unable to write it to file 😦


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