Exclusive cron task lock with flock

If you need ensure to run cron task only once at time, you can use file lock with flock

Add those templates to your schedule.rb

# usage script_with_lock 'script_name', lock: 'lock_name'
job_type :script_with_lock, "cd :path && :environment_variable=:environment flock -n /var/lock/:lock.lock :bundle_command script/:task :output"
# usage runner_with_lock 'ruby code', lock: 'lock_name'
job_type :runner_with_lock, "cd :path && flock -n /var/lock/:lock.lock :bundle_command :runner_command -e :environment ':task' :output"

• Compare to the build-in templates here: https://github.com/javan/whenever/blob/master/lib/whenever/setup.rb#L27-L30
• see man flock for information about what -n means. It's likely you do not want it.