Cron

Work with five-field cron expressions (minute hour day-of-month month day-of-week): read single fields, build and normalise expressions, convert between the string form and a map with one key per field, describe a schedule in words, and check that an expression is valid.

Reference

Functions

cronDescribe

cronDescribe describes a cron expression in words, for display: “Every 5 minutes”, “At 02:00 on Monday through Friday”. Expressions it cannot put into words come back as “Cron: <expression>”; “Invalid cron expression” when expr is not a five-field expression or a macro.

{{ cronDescribe "0 2 * * 1-5" }}  → "At 02:00 on Monday through Friday"
{{ cronDescribe "*/15 * * * *" }}  → "Every 15 minutes"

See also: cronValid, nextCron

cronDom

cronDom returns the day-of-month field of a cron expression; “*” for an empty expression, and an error when it does not have five fields.

{{ cronDom "0 0 15 * *" }}  → "15"

cronDow

cronDow returns the day-of-week field of a cron expression; “*” for an empty expression, and an error when it does not have five fields.

{{ cronDow "0 0 * * 1" }}  → "1"

cronExpr

cronExpr builds a five-field cron expression from five explicit string parts. Empty parts default to *.

{{ cronExpr "*/15" "" "" "" "1-5" }}  → "*/15 * * * 1-5"

cronField

cronField extracts a field by index (0–4). The general form of the five named extractors above.

{{ cronField "*/5 2 * * 1" 1 }}  → "2"

cronFromAny

cronFromAny converts a schedule value to a five-field cron string. Accepts either shape:

{{ cronFromAny .spec.schedule }}  → "*/5 0 * * 1"
{{ cronFromAny "0 2 * * *" }}    → "0 2 * * *"

cronFromMap

cronFromMap converts a schedule map to a five-field cron string. Reads keys minute, hour, dayOfMonth, month, dayOfWeek; absent keys default to *. Errors if the input is not a map — use cronFromAny when the input may be a string.

{{ cronFromMap .spec.schedule }}  → "*/5 0 * * 1"

cronHour

cronHour returns the hour field of a cron expression; “*” for an empty expression, and an error when it does not have five fields.

{{ cronHour "*/5 2 * * 1" }}  → "2"

cronMinute

cronMinute returns the minute field of a cron expression; “*” for an empty expression, and an error when it does not have five fields.

{{ cronMinute "*/5 2 * * 1" }}  → "*/5"

cronMonth

cronMonth returns the month field of a cron expression; “*” for an empty expression, and an error when it does not have five fields.

{{ cronMonth "0 0 1 6 *" }}  → "6"

cronNormalize

cronNormalize normalizes a cron string: expand @-macros, trim whitespace, ensure exactly five fields. Returns "* * * * *" for empty or malformed input.

{{ cronNormalize "@daily" }}  → "0 0 * * *"

cronToMap

cronToMap converts a cron string to the structured map shape. For use in conversion path specs only — the result is a nested map, not a plain string.

{{ (cronToMap "*/5 0 * * 1").minute }}  → "*/5"

cronValid

cronValid reports whether expr is a valid five-field cron expression, with every field in range. Macros (@daily), steps, ranges and lists are accepted.

{{ cronValid "0 2 * * 1-5" }}  → true
{{ cronValid "0 25 * * *" }}   → false