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CLAUDE.md — dolphinscheduler-scheduler-plugin

Plugin family for the cron-trigger scheduler that fires workflows at their scheduled times. Only one implementation today (Quartz), but the SPI is in place so alternatives can be added.

This directory is a Maven parent POM.

Sub-modules

  • dolphinscheduler-scheduler-api — the SchedulerApi interface (start, insertOrUpdateScheduleTask, deleteScheduleTask, close) + related DTOs.
  • dolphinscheduler-scheduler-quartz — Quartz-based implementation. QuartzScheduler (SchedulerApi impl), QuartzSchedulerAutoConfiguration, QuartzSchedulerDataSourceAutoConfiguration, QuartzTriggerBuilder.
  • dolphinscheduler-scheduler-all — uber module consumed by master.

Who triggers what

  1. User defines a schedule in the UI → API persists a row.
  2. Master's leader starts the scheduler; SchedulerApi.insertOrUpdateScheduleTask registers the Quartz job.
  3. When Quartz fires, it inserts a t_ds_command row (WorkflowScheduler → CommandService). Master's command consumer picks it up and runs the workflow.

Gotchas

  • Only the master leader runs the scheduler. Non-leader masters hold SchedulerApi.close()-like quiet state. Electing a new leader must re-register all schedules.
  • Separate Quartz datasource: QuartzSchedulerDataSourceAutoConfiguration configures its own datasource pointing at the same DB as DolphinScheduler but with Quartz's own tables (QRTZ_*). Upgrades must run Quartz's own DDL as well as DolphinScheduler's.
  • Job key scheme: jobKey concatenates projectId_scheduleId. Renaming this scheme breaks in-flight scheduled tasks — avoid.
  • Cron parsing happens in two places: dolphinscheduler-service/cron uses cron-utils for display (next fire time in UI); Quartz internally uses Quartz cron syntax for firing. The two are mostly compatible but DOW conventions differ slightly — always validate with both.
  • Do not couple to Quartz types outside this module. Callers must depend on SchedulerApi, never on org.quartz.Scheduler directly.

Extension points

A new scheduler implementation would: (1) create a sibling sub-module; (2) implement SchedulerApi; (3) register via Spring Boot spring.factories / AutoConfiguration.imports; (4) add itself to scheduler-all.

Tests

Inside -quartz/src/test/java.

Related modules

  • dolphinscheduler-master — consumes scheduler-all.
  • dolphinscheduler-service — uses CronService for next-fire-time display (independent of this module's runtime).