Use globally defined log attribute key names across all services and packages

[pbleser-oc]

Description

Due to the lack of top-level definitions of constants for common (and possibly not-quite-so-common) log attribute key names across all packages and services, we are at risk of using different names for attributes.

That, in turn, can be detrimental when logs are ingested by log aggregation systems, since they prevent effectively performing search queries across those attributes (for example a userid).

Having different names of such attributes would require performing a query such as

http_response_code:500 AND (username:alan OR userid:alan OR userID:alan)

instead of just using

http_response_code:500 AND username:alan

Recommendation

Recommendation would be to implement a top-level package, or use pkg/log to define such constants that can be reused across all services.

For example, having a pkg/log/logconst.go file:

package log

const (
 UserId = "userid" // the internal user identifier
 UserName = "username" // the short name of the user
)

Then those could be reused across services when logging:

  logger.Error().Err(err).Str(log.UserId, ...).Str(log.UserName, ...).Msg("failed to find user in LDAP")

cc @rhafer @aduffeck would love to have your input on this