Using Excel as log reader. How to write to log file if Excel has it open?

Question

I've come into a position where all the existing scheduled applications write their logs to .CSV files, so that people can open them in Excel. The problem comes when someone opens a log file and just leaves it open. The applications then can't write to their logs, and by rule, they die.

So the options are:

somehow get the users to open the files in Excel in a non-exclusive manner;
somehow be able to write to the log despite the users' rudeness;
write a kinder, gentler log reader (nope, the company runs on Excel and .csv files and they won't change);
???????

Or am I just missing a totally brainless way to deal with this?

Most of the apps are currently VBScript, but I've already managed to convert many of them to C# console apps, so answers in both styles are welcome.

Use NTFS permissions to only allow read access by your users. — Phylogenesis, Apr 17 '15 at 15:47
i would not let the users touch my precious log files, instead you might provide a way for indirect access — Michael Sander, Apr 17 '15 at 15:48
i agree with @MichaelSander I'd never let users touch my actual log files. Instead I'd probably make back up copies some where for them to view. — Dom, Apr 17 '15 at 16:10

score 4 · Accepted Answer · answered Apr 17 '15 at 16:11

4

If you set NTFS permissions on the folder containing the CSV files appropriately so that your users only have read access whilst the user your scheduled tasks are running as has full access, then Excel will open the files in Read Only mode.

This will prevent Excel from holding a lock on the files and allow your logging to continue unhindered.

answered Apr 17 '15 at 16:11

Phylogenesis

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Of course... I do have some additional complications, but that puts me on the right track. I think I'll also write to a hidden directory and have a file system watcher copy them to the standard directory. – royatl Apr 17 '15 at 16:38

score 0 · Answer 2 · answered Apr 17 '15 at 16:03

You could potentially make use of a logging framework like Serilog.

When you configure Serilog, you can define multiple outputs (Serilog calls them Sinks). So, for example, you could configure your applications to write to a Windows Event Log as well as a CSV file. Your applications could continue to log to the Event Log even if someone has a CSV file open.

An example configuration could be:

var log = new LoggerConfiguration()
   .WriteTo.File("log.csv")
   .WriteTo.EventLog("My App")
   .CreateLogger();

Then, to write to the log, you simply need:

log.Information("This is a sample log entry");

There are some other elements which need to be set up, but the documentation on their website is great and will get you started.

Serilog is very lightweight and quick to configure so it wouldn't take too much effort to update your applications to use it.

Here is the Serilog homepage: https://github.com/serilog/serilog/wiki

I'd highly recommend it as a logging framework.

(I am not involved in the project - just a big fan having used it multiple times in projects I've worked on).

Thanks. That won't solve my immediate problem, but I do need to move these apps toward a more sophisticated framework. — royatl, Apr 17 '15 at 16:40

Using Excel as log reader. How to write to log file if Excel has it open?

2 Answers2