Usage Output

Table of Contents

Logged data

Have look into the directory after your first job was run.

/var/tmp/cronlogs/

The wrapper stores 3 information in different files

  • The output of the last execution of a job
  • a flagfile with a timestamp in it (0 byte)
  • a daily log file with all executions of all jobs and their returncodes

The filenames contain the hostname (taken from hostname -f) and the label of the job (which is generated or given as 3rd param).

Logfile

The created output of a cronjob look like this:

cat /var/tmp/cronlogs/[your-logfile]*.log

REM --------------------------------------------------------------------------------
REM CRON WRAPPER - www.example.com
REM --------------------------------------------------------------------------------
SCRIPTNAME=[Commandline of executed job]
SCRIPTTTL=30
SCRIPTSTARTTIME=2022-09-22 09:48:58, 1663832938
SCRIPTLABEL=testjob
SCRIPTPROCESS=32396
REM --------------------------------------------------------------------------------
REM OK, executing job the first time
JOBEXPIRE=1663837438
REM --------------------------------------------------------------------------------
SCRIPTENDTIME=2022-09-22 09:48:12, 1663832938
SCRIPTEXECTIME=14 s
SCRIPTRC=0
REM --------------------------------------------------------------------------------
SCRIPTOUT=[OUTPUT LINE 1]
SCRIPTOUT=[OUTPUT LINE 2]
SCRIPTOUT=...
SCRIPTOUT=[OUTPUT LINE N]
REM --------------------------------------------------------------------------------
REM /opt/cronwrapper/cronwrapper.sh finished at Do 22 Sep 2022 09:48:58 CEST

Syntax

You see lines with

  • REM - comment lines (to make the output file more readable)
  • [VARIABLE] = [Output]

This simple syntax was chosen to use a normal grep command to scan for a specific information.

To search for a specific information, i.e. the return code (SCRIPTRC) of your script

grep "^SCRIPTRC" /var/tmp/cronlogs/[your-logfile]*.log

… or all last execution resultcode of each job on the machine:

grep "^SCRIPTRC" /var/tmp/cronlogs/*.log

The last command tests the returncode only.

Variables

To detect outdated jobs see section for cronstatus.sh on the next page.

value type description
SCRIPTNAME string commandline of executed job; The value is taken from 1st parameter of cronwrapper commandline
SCRIPTTTL integer TTL value: in how many minutes this cronjob wust be repeated? The value is taken from 2nd parameter of cronwrapper commandline
SCRIPTSTARTTIME datetime starting time of the cronjob as time and (after comma) as unix timestamp; eg. 2022-09-22 09:48:58, 1663832938
SCRIPTLABEL string label that will be part of the flag file and the log file name in the output directory. By default it is generated but you can override it with a 3rd parameter in cronwrapper commandline
SCRIPTPROCESS integer process id
JOBEXPIRE integer Unix timestamp when the job is expired. t is calculated by starttime plus TTL
SCRIPTENDTIME datetime ending time of the cronjob as time and (after comma) as unix timestamp; eg. 2022-09-22 09:48:12, 1663832938
SCRIPTEXECTIME string Needed time for execution in seconds as human readable time; the delta of endtime - starttime; the time for execution of hooks is excluded
SCRIPTRC integer returncode of the executed commandline
SCRIPTOUT string Output of the executed command. This value can be repeated in the log on multiline outputs

flagfile

The flagfile is a zero byte file with a generated filename from label, expiration time and hostname. The label correspondents to a log file.

The flagfile will be touched if a cronjob was finished.

joblog

The daily joblog exists for jobs that run several / many times per day. It stores the Label of a job, the starting time and a result code.

You have the results and exectime for all started jobs of the last 6 weekdays in the log diectory. The log of the 7th day automatically will be removed.

axel@linux-pc /v/t/cronlogs> pwd
/var/tmp/cronlogs

axel@linux-pc /v/t/cronlogs> ls -1 *joblog*
linux-pc_joblog_20240317-Sun.done*
linux-pc_joblog_20240318-Mon.done*
linux-pc_joblog_20240319-Tue.done*
linux-pc_joblog_20240320-Wed.done*
linux-pc_joblog_20240321-Thu.done*
linux-pc_joblog_20240322-Fri.done*
linux-pc_joblog_20240323-Sat.done*
linux-pc_joblog_20240324-Sun.done*
linux-pc_joblog_20240325-Mon.done*
linux-pc_joblog_20240326-Tue.done*
linux-pc_joblog_20240327-Wed.done*
linux-pc_joblog_20240328-Thu.done*
linux-pc_joblog_20240329-Fri.done*
linux-pc_joblog_20240330-Sat.done*
linux-pc_joblog_20240331-Sun.done*
linux-pc_joblog_20240401-Mon.done*

Let’s have look to it:

axel@linux-pc /v/t/cronlogs> head -3 linux-pc_joblog_20240401-Mon.done
job=restic-backup:host=linux-pc:start=1711922820:end=1711922937:exectime=117:ttl=60:rc=0
job=restic-backup:host=linux-pc:start=1711926420:end=1711926532:exectime=112:ttl=60:rc=0
job=restic-backup:host=linux-pc:start=1711973220:end=1711973399:exectime=179:ttl=60:rc=0

With a delimter : you see these data (values like in the job logs)

  • job - label of the job
  • host - hostname
  • start - starttime as unix timestamp
  • end - endtime as unix timestamp
  • exectime - execution time of the job in sec
  • ttl - the ttl value
  • rc - return code
  • blockedbypid - optional: when using option SINGLEJOB=1 and a 2nd job will be executed you get the pid that blocked its execution.