1668474 - Make `NSPR_LOG_MODULES=printing:5` useful

Status: NEW

(Core :: Printing: Setup, task, P2)

Description

[Jonathan Watt [:jwatt]]

We have some print debug logging that is turned on using NSPR_LOG_MODULES=printing:5 (or NSPR_LOG_MODULES=printing:5,printing-layout:5 to also include the printing layout logging). This logging can be turned on, even in Release builds, but its output is currently really not very useful.

Now that we're making printing smarter and more aware of printer capabilities, we're encountering more issues with printers and print libraries such as CUPS. Given the huge number of permutations of OSs, OS versions, system libraries, CUPS versions, printers, printer drivers, connection methods, etc., it is often not possible for us to reproduce issues and debug them locally. It would therefore be very helpful to have useful NSPR_LOG_MODULES logging that could help us narrow down the issues some users are having.

A few things that come immediately to mind are:

• The initiation and success/failure of the various nsIPrinterList APIs, and the APIs of the other interfaces accessed via that interface (preferably including serializing values into the log output).
• The recieving of RecvPrintPreview, RecvExitPrintPreview and RecvPrint.
• The nsPrintJob entry points, and various key milestones (which?)

Other suggestions welcome!

Comment 1

[Jonathan Watt [:jwatt]]

Maybe best to have this as a meta bug I guess, and spin off individual bugs for logging of various pieces of code.