Re: application logging strategy - advice - C# Discussion Boards

25-Oct-12 4:22

In my applications (generally WinForms) I am currently using Log4Net to allow me to use application logging.

my question is that currently I log at exception levels, but I feel that this level of logging is not enough.

what I am asking is advice / help or even pointers to a good logging strategy.

Thanks
Simon

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Richard MacCutchan25-Oct-12 6:23

Richard MacCutchan

25-Oct-12 6:23

As with most things: it depends. I have worked on systems which can log just about everything that happens in the program to those that do not properly log (or catch) exceptions. One of the options you could try is to add code that will log every method call, entry and exit, including parameters and return values, but make it optional, so you only enable it when trying to locate a problem. You can also try logging particular types of activity based on flags or debug levels etc.

One of these days I'm going to think of a really clever signature.

R. Giskard Reventlov25-Oct-12 6:37

R. Giskard Reventlov

25-Oct-12 6:37

Good advice.

It might also depend upon what the application is doing. For instance, on a windows service, I tend to log everything because it might be useful to have a record of what is going on each time the application carries out its tasks and to check that it has done so properly.

All according to need. I also use log4Net: pretty good piece of kit.

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Simon_Whale25-Oct-12 11:50

25-Oct-12 11:50

Thanks Richard,

what you have suggested makes a lot of sense.

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Eddy Vluggen25-Oct-12 8:41

Eddy Vluggen

25-Oct-12 8:41

Simon_Whale wrote:
my question is that currently I log at exception levels, but I feel that this level of logging is not enough.

Can you objectively point out where you lack logging and which part needs additional tracing?

You could trace every sql-statement on the database-server, log a lot of actions and events, and even log the information on the network. You could "always" run the app in debug-mode, using a custom debugger to log everything.

If you're hunting exceptions in the wild, you might want to make minidumps[^]. That's not logging, but might still be what you're after.

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Simon_Whale25-Oct-12 12:01

25-Oct-12 12:01

Thanks Eddy

The application is a complete back office for an insurance underwriters which I work for, at present I felt with just capturing the exception and the data that caused the issue it gave me a wild goose chase to find the area that caused the problem, as not all the time does the user give you a full picture of what they were doing.

but with information from yourself and Richard I now have a lot of things that I can do to make logging a good debugging tool.

Thanks
Simon

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jschell25-Oct-12 10:43

jschell

25-Oct-12 10:43

Simon_Whale wrote:
what I am asking is advice / help or even pointers to a good logging strategy.

There are several definitions for logging. I have taken to using the following definitions.
1. Audit logging. This involves tracking what 'users' are doing on the system. For example if a user deletes a record then a 'audit log' is created. This can be driven 'users' that are not actually people such as a 3rd party application.
2. Operations logging. This is information collected specifically to assist operations staff in diagnosing expected error conditions. For example if a third party web service goes down then operations needs to know about it.
3. Trace logging. This is logging that assist a developer in determining why a system failed due to unexpected problems. It will often require familiarity with the code base to understand everything.

Audit logging is defined by business requirements.
Operations logging is defined mostly by operations but can be guessed at by development.
Trace logging is solely dependent on development making educated guesses about failure points.

Specifically for trace logging...

Trace logging does NOT work if it does not exist in the production system. Thus trace logging is NOT a tool that is used during development. That doesn't mean you can't add logging to figure out some obscure problem while you are writing code but it does mean that the logging statements that are left in must be manageable in production.

It also means that logging must exist in the production system. It is not turned off nor turned down.

Trace logging can be used by operations but operations does not dictate, control nor otherwise own it. Operations can make suggestions for improvements but consideration should be given that operations has their own log and thus most times what they want should be in there and not in the trace log.

In general logging (trace logging) cannot use a off box repository (database,etc) because both of those can fail. And with such failures there must be some way to log that.

Trace logging must not stop the real application from running. Compare this to audit logging which one might code such that the application stops working if it can no longer do audit logging.

With smaller systems it often seems possible and desirable to do things like log the entry and exit from every major method. However that is impossible in systems will larger volumes. Both because the log files can become large very quickly (think 10 of gigs daily or larger) and because finding anything when there is a lot of data becomes a problem.

So addressing large system only one can come up with the following
- Log exceptions but insure that they only log once. In practice this means that if you catch an exception and log it you do NOT re-throw it.
- Log entry and exit (including success/failure) from major functional areas.
- Provide a trace id for every message in the application and even better in the system. When logging relevant to message processing then always log with that id.
- Log off box request/response attempts. This includes success and failure. Especially when going to a 3rd party.
- Avoiding logging in looping structures. This is to reduce noise. Logging at the beginning and the end is sufficient.
- Avoid duplicate logging. If you load configuration information don't log it every time you access the configuration information, but only the first time.
- Log messages must contain relevant information. Thus don't log "x=3" but instead "result of order query=3"
- Log messages are not a dumping ground for development. Developers must keep in mind that the log file is not an infinite resource and also keep in mind that although they will need to use it to debut problems that unnecessary log lines can multiply hundreds of thousands of times in production and thus make it that much harder to determine problems. The log file provides assistance but not solutions to unknown problems.

Another trick that I have found valuable works in some scenarios with exception handling.
- This is often a boundary layer system.
- I catch an exception, log it along with an id (GUID).
- I throw another exception with a message that is appropriate for the boundary layer and I include the id as part of the message.

The advantage of the above is that upstream, perhaps a user or a third party system gets an error message that means something to them. And questions about that can be address in the context of finding the exception cause in the log file with the id if that becomes necessary.

Simon_Whale25-Oct-12 12:02

25-Oct-12 12:02

Thanks jschell

that has given me great things to read and use Big Grin | :-D

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applicatin developing in c#

V.25-Oct-12 21:10

25-Oct-12 21:10

I've done some fair logging and mostly the needs depend a little on the application.
There are several questions that need to answering:

1. What
Despite the actual text you might want to log off course, the datetimestamp (go millisecond or smaller!), but also who was the user at the time, what machine, which application, module, class, method and finally you'll need a log type (error, warning, information,...) and severity.

2. When
Concerning the actual log message I usually log every exception and the SQL statements.  Then mostly I add logging at key points eg when receiving information from a webservice call or when we send an email succesfully, ...

3. Where
Mostly one logs to a txt file or something like that.  I find that horrible personally.  If you have one application, no problem, but if you have a system, log to the database.  It will be easier to trace the sequence instead of going through five log files at the same time comparing datetime stamps.  It is always possible to catch a db down and write to txt file as backup.

4. How
Prevent in using a method inside each class, create an assembly that can be used by all applications.  Built in a debug level setting that will prevent logging too verbose when not required.

Hope this helps.

V.

(MQOTD Rules and previous Solutions )

krishnaveni_g24-Oct-12 23:29

krishnaveni_g

24-Oct-12 23:29

sample application developing in c#

Eddy Vluggen24-Oct-12 23:35

Eddy Vluggen

24-Oct-12 23:35

You can find samples in various books, and even on Microsofts' website. There's samples on this website too.

Start here[^].

Bastard Programmer from Hell Suspicious | :suss:

if you can't read my code, try converting it here[^]

Sivaraman Dhamodharan24-Oct-12 23:47

Sivaraman Dhamodharan

24-Oct-12 23:47

You can refer here also.

Programming Article

My vote of 1

Keith Barrow25-Oct-12 2:49

Keith Barrow

25-Oct-12 2:49

This isn't even a question. You want a sample application (bad enough - why should we do your work for you) but don't describe what it is that you want (which could range from a "hello world" application to modelling the universe).

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

Vasudevan Deepak Kumar25-Oct-12 8:54

Vasudevan Deepak Kumar

25-Oct-12 8:54

If you are still a sophomore, you can be pardoned and I would suggest a read of Some guidelines for posting questions in the forums[^]

But if you are working in some organization, I would seriously need to know the management of the organization and shoot down the CEO mercilessly because you are just one sample of the whole bunch of rotten apples waiting to spoil the face of entire developer fraternity.

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V.26-Oct-12 2:39

26-Oct-12 2:39

countered downvote Thumbs Up | :thumbsup:

V.

(MQOTD Rules and previous Solutions )

gopal pradhan8-Nov-12 23:33

gopal pradhan

8-Nov-12 23:33

Try this link

Some Best Practices for C# Application Development (Explained)[^] Smile | :)