
Ask HN: How do you monitor your background jobs? - kostarelo
When you have many background jobs, that take either a few seconds or lots of minutes&#x2F;hours, how do you monitor them?<p>How do you know when they started and when they finished, their outcome, etc. Do others, non-tenchical folks, need access to that or is it just the developers?
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simonblack
Most background jobs are run by cron.

Cron has the capability to set environment variables. The scripts/programs can
check those variables and then have the ability to adjust the type and
quantity of logging according to whether they are run as cron jobs or from the
command-line.

The logging of these jobs goes to a specific log file which is rotated daily.
The daily logs are kept for 10 days before being discarded.

For instance this is a cron entry. Note the logfile argument as $1.

    
    
         # update BAK_MONTHLY on 2nd of the month only
         24 09 2 * *         /home/jvs/binscripts/rsync.bak.monthly.xpz /var/log/cronlog_jvs
    
    

This is cron setting variables in the crontab file

    
    
         # DO NOT EDIT THIS FILE - edit the master and reinstall.
         # tell cronjobs that they are running under cron
         CRONJOB=CRONJOB
         # specify the logfile for cronjobs output
         LOGFILE=/var/log/cronlog_jvs
         # expand the path
         PATH=/usr/sbin:/sbin:/usr/local/sbin:/usr/bin:/bin:/usr/local/bin:/home/jvs/binscripts
         #
         # m h  dom mon dow   command
    
    

and this is a cronjob template

    
    
         #!/bin/bash
         #jvs script
         #
         # DATE WRITTEN ......
         #
         # This crontab item does ........
         #
     
         #Set variables
         TARGET=
         NOW=$(date +%y%m%d)
         DAY=$(date +%d)
         LOGFILE="/tmp/${HOSTNAME}.crontab-item.log"
     
         if [ "$1" != "" ]; then
            LOGFILE="$1"
         fi
     
         touch "$LOGFILE"
         chmod 666 "$LOGFILE"
     
         echo -e "#######################################################\n " >>"$LOGFILE"
         /bin/date +"%F %H%M" >>"$LOGFILE" 2>&1
         echo "$0" >>"$LOGFILE"
     
     
         ### ***************************************************
         ### *******   Guts of crontab item goes here   ********
         ### ***************************************************
     
         # Say when this item completed
         echo -e "\n$0 Completed at $(date)" >>"$LOGFILE"

