Logging from multiple processes to same file using Enterprise Library 4.1

Question

I have several processes running concurrently that I want to log to the same file.

We have been using Enterprise Library 4.1 Logging Application Block (with a Roll

Answer 1

EntLib locks the log file when it writes to it. Therefore, 2 processes cannot write to the same log file.

When we have had this problem, that we needed to log from many difference places, to the same place, we have used database logging.

If you are 100% stuck logging to a text file, then you could log to individual log files, and then write a program to merge these files.

Answer 2

The problem occurs when the App Pool Recycles and allows for Overlapping Threads. The closing thread has it still open, and the new thread gets the error. Try disabling the overlapping recycling behavior in IIS, or create your own version of the text writer.

Answer 3

Sorry to say but the answer is no. The File TraceListeners lock the output file so only one TraceListener can log to a file.

You can try other Trace Listeners that are not file based (e.g. Database, Event Log).

Another option I can think of would be to write your own logging service (out of process) that would log to the file and accepts LogEntries. Then create a custom trace listener that sends a message to your service.

It might not be a good idea since you would have a bit of custom development plus it could impact performance since it is an out of process call. Basically you are setting up your own simplified-pseudo-distributor-service.

Answer 4

I know this is old, but if you are still curious. log4net supports this:

http://logging.apache.org/log4net/release/faq.html#How do I get multiple process to log to the same file?