No path formats supported

[LarsWesselius]

It seems the extension WriteTo.File does not support path formats like the 'old' RollingFile does. I see Specifier.cs from serilog-sinks-rollingfile and TemplatedPathRoller which is very similar to the PathRoller found in this project.

It seems easy to support path templating here (since the code is very similar and can be transferred), but maybe I'm missing something here; was not templating in this project intentional? If so, why?

Thanks!

[amoerie]

At first glance, it would appear that these formats are now hardcoded into https://github.com/serilog/serilog-sinks-file/blob/dev/src/Serilog.Sinks.File/RollingInterval.cs

[LarsWesselius]

Correct, as a result you end up with a hardcoded filename as per the README. My format is log-{Hour}.txt and the file ended up as log-{Hour}201710241211.txt

[nblumhardt]

@LarsWesselius thanks for the note; yes, the decision was intentional - the original design of RollingFile, though I really like it aesthetically, doesn't work the way people expect it to:

• Custom :xxx formats aren't supported, and are unlikely to be, because they'd require translation to equivalent regular expressions in order for precise file set detection to work
• Arbitrary properties from log events can't appear in the path, even though the syntax is identical to the output template syntax used elsewhere
• Template placeholders can't appear in directories in the path, only files
• Multiple templates can't appear in the same path, e.g. /{Year}/{Month} etc.

File's rolling is making a clean break - it'd be great to implement all of these things in RollingFile someday, but for a stable, core package, I think the simpler approach in File is the better one for now.

@amoerie the formats are hard-coded in Serilog.Sinks.RollingFile as well - https://github.com/serilog/serilog-sinks-rollingfile/blob/dev/src/Serilog.Sinks.RollingFile/Sinks/RollingFile/Specifier.cs#L22 :-)

[LarsWesselius]

@nblumhardt Fair points, thanks. It is a shame though that the yyyMMddHHmm format is not editable. I don't like how it looks personally. Might fork it and use my own format for a bit.

One additional question based on your comment; you mention you'd like to implement all of those things into RollingFile but I was under the impression the File package was the new 'standard' if you will. How are these packages going to co-exist in the future?

Thanks again!

[nblumhardt]

Hi Lars,

It is a shame though that the yyyMMddHHmm format is not editable.

I think a customizable format is a fair feature to add, I definitely wouldn't rule it out in the future, but doing a good job of it seems like it will be non-trivial. Needs a lot of careful analysis around filename parsing, anyway - having the sink delete files that it didn't create is something of a doomsday scenario :-) It would also be necessary to ensure that whatever format is used can be reliably parsed to the right resolution - yyyy is never going to work for a monthly rolling file, for example, and that locale doesn't cause anything crazy to happen. Need to figure out the constraints and how we might detect problems.

How are these packages going to co-exist in the future?

Serilog.Sinks.RollingFile is so widely-used I don't think it'll become "legacy" in the near future - we'll encourage people to use the File package, but if someone took the lead on RollingFile there's room for it to continue evolving. (Having the more conservative File implementation actually takes some of the pressure off of RollingFile - perhaps it can even move a bit faster now! :-))

[LarsWesselius]

Hey,

Thanks for the explanation :)
I'll keep a close eye on the projects going forward.