7e5abd504f
Add three DBOS SDK skills with reference documentation for building reliable, fault-tolerant applications with durable workflows. Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
70 lines
2.0 KiB
Markdown
70 lines
2.0 KiB
Markdown
---
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title: Create Scheduled Workflows
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impact: MEDIUM
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impactDescription: Enables recurring tasks with exactly-once-per-interval guarantees
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tags: pattern, scheduled, cron, recurring
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---
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## Create Scheduled Workflows
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Use `dbos.WithSchedule` when registering a workflow to run it on a cron schedule. Each scheduled invocation runs exactly once per interval.
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**Incorrect (manual scheduling with goroutine):**
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```go
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// Manual scheduling is not durable and misses intervals during downtime
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go func() {
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for {
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generateReport()
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time.Sleep(60 * time.Second)
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}
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}()
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```
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**Correct (using WithSchedule):**
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```go
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// Scheduled workflow must accept time.Time as input
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func everyThirtySeconds(ctx dbos.DBOSContext, scheduledTime time.Time) (string, error) {
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fmt.Println("Running scheduled task at:", scheduledTime)
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return "done", nil
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}
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func dailyReport(ctx dbos.DBOSContext, scheduledTime time.Time) (string, error) {
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_, err := dbos.RunAsStep(ctx, func(ctx context.Context) (string, error) {
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return generateReport()
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}, dbos.WithStepName("generateReport"))
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return "report generated", err
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}
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func main() {
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ctx, _ := dbos.NewDBOSContext(context.Background(), config)
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defer dbos.Shutdown(ctx, 30*time.Second)
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dbos.RegisterWorkflow(ctx, everyThirtySeconds,
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dbos.WithSchedule("*/30 * * * * *"),
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)
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dbos.RegisterWorkflow(ctx, dailyReport,
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dbos.WithSchedule("0 0 9 * * *"), // 9 AM daily
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)
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dbos.Launch(ctx)
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select {} // Block forever
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}
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```
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Scheduled workflows must accept exactly one parameter of type `time.Time` representing the scheduled execution time.
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DBOS crontab uses 6 fields with second precision:
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```text
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┌────────────── second
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│ ┌──────────── minute
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│ │ ┌────────── hour
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│ │ │ ┌──────── day of month
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│ │ │ │ ┌────── month
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│ │ │ │ │ ┌──── day of week
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* * * * * *
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```
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Reference: [Scheduled Workflows](https://docs.dbos.dev/golang/tutorials/workflow-tutorial#scheduled-workflows)
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