`syslog` support

[Mathieu-Lala]

vSMTP will support logging to standard operating system.

syslog and tracing_journald can be used for that.

In some context, you might not want to have these feature enabled. Should I wrap them under --features syslog and --features journald ?

[paguardiolle]

Imho syslog behavior must be included in the vsmtp.toml file. Do not forget that vSMTP is a daemon and not a "command line" application.

Syslog requires:

On | Off Level Format Socket (done ?) Category "mail" hardcoded (done)

... and the corresponding vBook chapter must be rewrite.

[Mathieu-Lala]

[server.syslog] # if the table is not specified, syslog is disabled
min_level = "info"
format = "3164" | "5424"
unix = "/dev/log"
# or
tcp = "127.0.0.1:601"
# or
udp = "127.0.0.1:514"

[paguardiolle]

Ok. But do not forget IPv6.

In a more concise (and Posix...) way:

socket = unix:/dev/log 
# or 
socket = inet:IPv4:port/proto
# or (mandatory)
socket = inet6:[IPv6]:port/proto