feat(logging): added log format option, #4590

conf/sample.ini

@@ -230,19 +230,26 @@ check_for_updates = true
 #################################### Logging ##########################
 [log]
 # Either "console", "file", "syslog". Default is console and  file
-# Use comma to separate multiple modes, e.g. "console, file"
+# Use space to separate multiple modes, e.g. "console file"
 ;mode = console, file
 
-# Either "Trace", "Debug", "Info", "Warn", "Error", "Critical", default is "Info"
-;level = Info
+# Either "trace", "debug", "info", "warn", "error", "critical", default is "info"
+;level = info
 
 # For "console" mode only
 [log.console]
 ;level =
 
+# log line format, valid options are text, console and json
+;format = console
+
 # For "file" mode only
 [log.file]
 ;level =
+
+# log line format, valid options are text, console and json
+;format = text
+
 # This enables automated log rotate(switch of following options), default is true
 ;log_rotate = true
 
@@ -258,6 +265,23 @@ check_for_updates = true
 # Expired days of log file(delete after max days), default is 7
 ;max_days = 7
 
+[log.syslog]
+;level =
+
+# log line format, valid options are text, console and json
+;format = text
+
+# Syslog network type and address. This can be udp, tcp, or unix. If left blank, the default unix endpoints will be used.
+;network =
+;address =
+
+# Syslog facility. user, daemon and local0 through local7 are valid.
+;facility =
+
+# Syslog tag. By default, the process' argv[0] is used.
+;tag =
+
+
 #################################### AMQP Event Publisher ##########################
 [event_publisher]
 ;enabled = false