Triggers

To configure a once an hour schedule, you specify a single time with the minute attribute.

For example, the following hourly schedule triggers at minute 30 every hour-- 12:30, 13:30, 14:30, and so on.

{
  ...

  "trigger" : {
    "schedule" : {
      "hourly" : { "minute" : 30 }
    }
  }
  ...
}

To configure an hourly schedule that triggers at multiple times during the hour, you specify an array of minutes. For example, the following schedule triggers every 15 minutes every hour--12:00, 12:15, 12:30, 12:45, 1:00, 1:15, and so on.

{
  ...
  "trigger" : {
    "schedule" : {
      "hourly" : { "minute" : [ 0, 15, 30, 45 ] }
    }
  }
  ...
}

To configure a once a day schedule, you specify a single time with the at attribute. For example, the following daily schedule triggers once every day at 5:00 PM.

{
  ...
  "trigger" : {
    "schedule" : {
      "daily" : { "at" : "17:00" }
    }
  }
  ...
}

To configure a daily schedule that triggers at multiple times during the day, you specify an array of times. For example, the following daily schedule triggers at 00:00, 12:00, and 17:00 every day.

{
  ...
  "trigger" : {
    "schedule" : {
      "daily" : { "at" : [ "midnight", "noon", "17:00" ] }
    }
  }
  ...
}

In addition to using the HH:mm string syntax to specify times, you can specify a time as an object that has hour and minute attributes.

For example, the following daily schedule triggers once every day at 5:00 PM.

{
  ...
  "trigger" : {
    "schedule" : {
      "daily" : {
        "at" {
          "hour" : 17,
          "minute" : 0
        }
      }
    }
  }
  ...
}

To specify multiple times using the object notation, you specify multiple hours or minutes as an array. For example, following daily schedule triggers at 00:00, 00:30, 12:00, 12:30, 17:00 and 17:30 every day.

{
  ...
  "trigger" : {
    "schedule" : {
      "daily" : {
        "at" {
          "hour" : [ 0, 12, 17 ],
          "minute" : [0, 30]
        }
      }
    }
  }
  ...
}

To configure a once a week schedule, you specify the day with the on attribute and the time with the at attribute. For example, the following weekly schedule triggers once a week on Friday at 5:00 PM.

{
  ...
  "trigger" : {
    "schedule" : {
      "weekly" : { "on" : "friday", "at" : "17:00" }
    }
  }
  ...
}

To configure a weekly schedule that triggers multiple times a week, you can specify an array of day and time values. For example, the following weekly schedule triggers every Tuesday at 12:00 PM and every Friday at 5:00 PM.

{
  ...
  "trigger" : {
    "schedule" : {
      "weekly" : [
          { "on" : "tuesday", "at" : "noon" },
          { "on" : "friday", "at" : "17:00" }
      ]
    }
  }
  ...
}

Alternatively, you can specify days and times in an object that has on and minute attributes that contain an array of values. For example, the following weekly schedule triggers every Tuesday and Friday at 12:00 PM and 17:00 PM.

{
  ...
  "trigger" : {
    "schedule" : {
      "weekly" : {
        "on" : [ "tuesday", "friday" ],
        "at" : [ "noon", "17:00" ]
      }
    }
  }
  ...
}

To configure a once a month schedule, you specify a single day and time with the on and at attributes. For example, the following monthly schedule triggers on the 10th of each month at noon.

{
  ...
  "trigger" : {
    "schedule" : {
      "monthly" : { "on" : 10, "at" : "noon" }
    }
  }
  ...
}

To configure a monthly schedule that triggers multiple times a month, you can specify an array of day and time values. For example, the following monthly schedule triggers at 12:00 PM on the 10th of each month and at 5:00 PM on the 20th of each month.

{
  ...
  "trigger" : {
    "schedule" : {
      "monthly" : [
          { "on" : 10, "at" : "noon" },
          { "on" : 20, "at" : "17:00" }
      ]
    }
  }
  ...
}

Alternatively, you can specify days and times in an object that has on and at attributes that contain an array of values. For example, the following monthly schedule triggers at 12:00 AM and 12:00 PM on the 10th and 20th of each month.

{
  ...
  "trigger" : {
    "schedule" : {
      "monthly" : {
        "on" : [ 10, 20 ],
        "at" : [ "midnight", "noon" ]
      }
    }
  }
  ...
}

To configure a once a year schedule, you specify the month with the in attribute, the day with the on attribute, and the time with the at attribute. For example, the following yearly schedule triggers once a year at noon on January 10th.

{
  ...
  "trigger" : {
    "schedule" : {
      "yearly" : { "in" : "january", "on" : 10, "at" : "noon" }
    }
  }
  ...
}

To configure a yearly schedule that triggers multiple times a year, you can specify an array of month, day, and time values. For example, the following yearly schedule triggers twice a year: at noon on January 10th, and at 5:00 PM on July 20th.

{
  ...
  "trigger" : {
    "schedule" : {
      "yearly" : [
          { "in" : "january", "on" : 10, "at" : "noon" },
          { "in" : "july", "on" : 20, "at" : "17:00" }
      ]
    }
  }
  ...
}

Alternatively, you can specify the months, days, and times in an object that has in, on, and minute attributes that contain an array of values. For example, the following yearly schedule triggers at 12:00 AM and 12:00 PM on January 10th, January 20th, December 10th, and December 20th.

{
  ...
  "trigger" : {
    "schedule" : {
      "yearly" : {
        "in: : [ "jan", "dec" ],
        "on" : [ 10, 20 ],
        "at" : [ "midnight", "noon" ]
      }
    }
  }
  ...
}

A cron expression is a string of the following form:

<seconds> <minutes> <hours> <day_of_month> <month> <day_of_week> [year]

All elements are required except for year. Table 4, “Cron Expression Elements” shows the valid values for each element in a cron expression.

The special characters you can use in a cron expression are described in Table 5, “Cron Special Characters”. The names of months and days of the week are not case sensitive. For example, MON and mon are equivalent.

Be careful when setting trigger times between midnight and 1:00 AM as daylight savings time changes can cause a watch to skip or a repeat depending on whether the time moves back or jumps forward.

To configure a cron schedule, you simply specify the cron expression as a string value. For example, the following snippet configures a cron schedule that triggers every day at noon:

{
  ...
  "trigger" : {
    "schedule" : {
      "cron" : "0 0 12 * * ?"
    }
  }
  ...
}

Watcher ships with a croneval command line tool that you can use to verify that your cron expressions are valid and produce the expected results. This tool is provided in the $ES_HOME/bin/watcher directory.

To verify a cron expression, simply pass it in as a string to croneval:

bin/watcher/croneval "0 0/1 * * * ?"

If the cron expression is valid, croneval displays the next 10 times that the schedule will be triggered.

You can specify the -c option to control how many future trigger times are displayed. For example, the following command displays the next 20 trigger times.

bin/watcher/croneval "0 0/1 * * * ?" -c 20

To configure an interval schedule, you simply specify a string value that represents the interval. If you omit the unit of time (s,m, h, d, or w), it defaults to seconds.

For example, the following interval schedule triggers every five minutes.

Hourly Schedule.

{
  ...
  "trigger" : {
    "schedule" : {
      "interval" : "5m"
    }
  }
  ...
}