How to share a logger between processes?

[ruipacheco]

My application needs to fork an unknown number of processes but I want them all to log to the same file at runtime. Is it possible and advisable to share an instance of shared_ptr between all processes?

[gabime]

The library does not support this. It could work, but it was not intended to be used this way.

[ruipacheco]

Do you think it's possible to add ZeroMQ as a sink? Or should I just write a message to a ZeroMQ socket and have a thread/process read from it and have that thread/process then write to spdlog?

[gabime]

Both options seem reasonable. Simpler option would be send thru a named pipe to a reading process that would write to the file

[ruipacheco]

I'm concerned about the second option because of timestamps - there will be a difference.

If spdlog were to write to 0MQ what would be sent? The string I just wrote or some sort of data structure with more than just the message?

[gabime]

I would just send the final formatted string to a named pipe which in turn would be consumed by a simple process that writes to file using spdlog ro directly. 0MQ is overkill for this.

This process can use spdlog to write to the actual file without reformatting the (already formatted) messages (set_formatter("%v")). This way the original timestamp would be preserved

[ruipacheco]

And then from 0MQ I'd have to write it to the file...

Ok, thanks, closing the issue.