Loggingand why it’s the shit.

You are going to love logging!

Ever had to debug a live issue and had no information to go on?

The aim of logging is to tell the story of what the application is doing

You tell the story to ILog

private static readonly ILog _log = LogManager.GetLogger(typeof(Foo));

There are 4 different log levels

Info

High level user activity

_log.InfoFormat( "User {0} has just logged in", user.Id);

Debug

Details of the internal logic of a method

_log.DebugFormat( "User {0} needs to pay {2} bills", user.Id, user.Bills.Count);

Warn

Something suspicious has happened from which we have recovered but...

if this happens a lot, we need to investigate

_log.WarnFormat( "User {0} tried to hack our servers", user.Id);

Error

Something went seriously wrong - this requires investigation because it means we have a bug.

_log.ErrorFormat( "Could not find User {0}’s bills", user.Id);

Where the hell are the logs aand how do we use them?

tail -f is your friend

Adding an identifier (e.g. user id) to your logs makes it easier to grep

Some do’s & don’ts

DO create a logger in every class you use

DON’T be afraid of doing LOTS of

logging

Questions?

Thanks to

Ed Devlin (Who initially came up with these guidelines)David Padbury (Who I stole these slides from)

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