{"id":19985,"date":"2014-01-28T12:30:50","date_gmt":"2014-01-28T10:30:50","guid":{"rendered":"https:\/\/mamchenkov.net\/wordpress\/?p=19985"},"modified":"2014-01-28T12:31:05","modified_gmt":"2014-01-28T10:31:05","slug":"3-things-to-remember-when-writing-cron-jobs","status":"publish","type":"post","link":"https:\/\/mamchenkov.net\/wordpress\/2014\/01\/28\/3-things-to-remember-when-writing-cron-jobs\/","title":{"rendered":"3 things to remember when writing cron jobs"},"content":{"rendered":"\n

Here is a reminder to myself with three things to remember when writing cron jobs. \u00a0Surprisingly, even after doing it fairly frequently for years and years, I still get caught by one of these once in a while.<\/p>\n

    \n
  1. User<\/strong>. \u00a0Just because the script is working fine under your user, it doesn’t mean it will work well from crontab. \u00a0Cron jobs are often executed under a different user account. \u00a0 Check, don’t assume. \u00a0And be noisy about permissions and other possibly related issues.<\/li>\n
  2. Environment<\/strong>. \u00a0This is slightly related to the previous point. \u00a0But just because something works fine from the command line, doesn’t mean it will run smoothly as a cron task. \u00a0Anything that requires particular environment variables, user input, or being executed in a specific directory should be double checked.<\/li>\n
  3. Duration<\/strong>. \u00a0Cron executes tasks on schedule. \u00a0It doesn’t really care if the previous instances finished running. \u00a0So, either make sure the script can run several instances simultaneously, or using a locking mechanism, to make sure two instances don’t step on each other’s toes.<\/li>\n<\/ol>\n\n","protected":false},"excerpt":{"rendered":"\n

    Here is a reminder to myself with three things to remember when writing cron jobs. \u00a0Surprisingly, even after doing it fairly frequently for years and years, I still get caught by one of these once in a while. User. \u00a0Just because the script is working fine under your user, it doesn’t mean it will work … Continue reading 3 things to remember when writing cron jobs<\/span><\/a><\/p>\n\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false,"_links_to":"","_links_to_target":""},"categories":[1,6,18,133,62],"tags":[],"keyring_services":[],"class_list":["post-19985","post","type-post","status-publish","format-standard","hentry","category-general","category-linux","category-programming","category-sysadmin","category-technology"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t