On Tuesday, 15 October 2013 at 15:21:52 UTC, Johannes Pfau wrote:
I think one increasingly important point for std.log is
'structured
logging'.
Structured logging is basically not simply logging textual
messages, but
also logging additional KEY/VALUE pairs of data. The idea is
that logs
should not only be readable by humans but also easy to parse and
analyze. Structured logging often also includes UUIDs to
simplify
finding similar errors/problems in a log file.
For example: Instead of logging
logf("Couldn't login as %s on server %s : Reason: %s", user,
server,
errorCode);
we'd do:
log(LOGIN_FAILED_UUID, "Couldn't log in", ["User": user,
"Server":
server, "ErrorCode": errorCode]);
The log can then be queried for all events with
'LOGIN_FAILED_UUID'
uuid, Server="..." ErrorCode=42, etc.
+1
I like the idea of structured logging.
I really need to log some complex data, not only string. I
usually use `to!string(value)` to convert complex data to string.
About syntax - we can use something like this:
log!(user, server, errorCode)(LOGIN_FAILED_UUID, "Couldn't log
in");
user, server and errorCode is variables passed to template. We
can get variable value as usually and variable name via
`__traits(identifier, variable)`, it should work after DMD 2.064.
For example, Vide.d use this idea, see `render` function:
http://vibed.org/docs
We can store complex data as string via `to!string(value)` cast
until we can use real backend implementation like SystemDs.
