G. Pape
socklog

socklog - log events notification

The service socklog-notify provides instant notification of log events. There is an interval in seconds for the creation of notifications to prevent a flood.

Set up the socklog-notify service as described in Configuration to ensure that the named pipe /var/log/socklog/.notify exists. Do not delete this file after creation.

Read disable notifications before stopping the socklog-notify service once it is started.

socklog-notify is handled by the uncat program.

How to configure log events

Choose a log controlled by svlogd to be watched for log events, say /var/log/socklog/main/.

Make sure the account running this log service is member of the socklog group adm. If it isn't, change it now. Make sure that the socklog-notify service is running.

Redirect the standard error output of svlogd to the named pipe socklog-notify is reading from. To do so, insert exec 2> /var/log/socklog/.notify as second line into /var/service/socklog-unix/log/run:

#!/bin/sh
exec 2> /var/log/socklog/.notify
exec setuidgid log svlogd \
  main/main main/auth main/cron main/daemon main/debug main/ftp \
  main/kern main/local main/mail main/news main/syslog main/user

svlogd's error messages are always log events.

To configure additional log events in /var/log/socklog/main/, use the e instruction in the config file of this log, see the svlogd man page. For example, if you want to be notified about all log messages of the priority alert, add a corresponding e instruction to the config file /var/log/socklog/main/config like this:

s999999
n10
e*.alert: *

Then tell the log service to re-read the config files:

sv hup socklog-unix/log

How to configure the notification

Per default, socklog-notify injects a mail to a specified address containing the log events, but the behavior is configurable, so you can change it to use instant or short messaging service for example.

To configure the kind of notification, edit /etc/sv/socklog-notify/run and change the prog argument of uncat to your needs. This example uses sms_client to notify:

#!/bin/sh -e
PIPE=/var/log/socklog/.notify
if [ ! -p "$PIPE" ]; then mkfifo -m0620 "$PIPE"; chown log:adm "$PIPE"; fi
exec <> "$PIPE"
exec setuidgid log uncat -s49999 -t90 \
  sh -c 'head -c140 | sms_client pager'

Then restart the service:

sv restart socklog-notify

Another example using wall:

exec setuidgid log uncat -vs49999 -t180 sh -c 'head | wall'

Disable log event notifications

You need to disable all log event notifications before stopping the socklog-notify service. To check which services are configured for sending log events, run:

grep -F /var/log/socklog/.notify /var/service/*/log/run

For each of these services, edit the corresponding log/run script to remove the exec 2>/var/log/socklog/.notify line and the configured log event(s) and restart its log service:

sv restart <service>/log

Now it is safe to stop the socklog-notify service.

Gerrit Pape <pape@smarden.org>