Timers and Scheduled Jobs: Patterns and Best Practices

In Service Studio, click the Processes tab (right panel — the stopwatch icon). You see 'Timers' in the tree. Right-click Timers → 'Add Timer'. Name it 'SendDailyDigestEmail'. In the Properties Panel for the new Timer: - Action: click the dropdown → select the Server Action to run (e.g., 'ProcessDailyDigest'). If the Server Action does not exist yet, create it first in Logic tab → Server Actions. - Schedule: the cron-like schedule (set in the next step) - Default Schedule Timeout: 20 minutes (platform default; increase for long-running jobs) If the Server Action does not yet exist: Logic tab → Server Actions → right-click → Add Server Action → name it 'ProcessDailyDigest'. You will fill in the logic in a later step.

Select the Timer in the Processes tab. In the Properties Panel, find the Schedule property. Click the expression field → the Schedule editor opens. OutSystems schedule syntax: - '00 00 8 * * *' — every day at 8:00 AM - '00 00 * * * *' — every hour at minute 0 - '00 */30 * * * *' — every 30 minutes - '00 00 8 * * 1' — every Monday at 8:00 AM (1=Monday, 7=Sunday) - '00 00 8 1 * *' — first day of every month at 8:00 AM Schedule field format: 'SS MM HH DD MO WD' (Seconds Minutes Hours DayOfMonth Month WeekDay) For a daily digest at 7 AM: Schedule = '00 00 7 * * *' For processing that runs every 15 minutes: Schedule = '00 */15 * * * *' All schedule times are in the server's local timezone. In ODC, all times are UTC — factor this into your schedule.

1/* Timer schedule examples */
2"00 00 7 * * *"    /* Every day at 07:00 */
3"00 00 8 * * 1"    /* Every Monday at 08:00 */
4"00 */15 * * * *"  /* Every 15 minutes */
5"00 00 2 1 * *"    /* First of each month at 02:00 */
6"00 30 17 * * 5"   /* Every Friday at 17:30 */

Open the ProcessDailyDigest Server Action. Timer Server Actions must be self-contained — they have no input parameters (timers start with no context) and typically no output parameters. Action flow for a batch email digest: Start → GetUsersForDigest Aggregate (filter: User.WantsDigest = True) → If: GetUsersForDigest.List.Empty → [True] End (nothing to process) → For Each User in GetUsersForDigest.List → SendDigestEmail Server Action (UserId = User.Id) → End Always add an AllExceptions handler to the Timer Server Action: Exception Handler (AllExceptions) → LogError('HRModule', 'ProcessDailyDigest', ExceptionMessage) → End (do NOT re-raise — let the timer complete without crashing) If you re-raise the exception inside a timer, OutSystems logs it as a timer failure in Service Center but the next scheduled run still fires. Catching and logging gives you more control over partial failure behavior.

1/* Server Action: ProcessDailyDigest */
2Start
3  --> Aggregate: GetUsersForDigest
4        Filter: User.WantsDigest = True and User.IsActive = True
5  --> If: GetUsersForDigest.List.Empty
6       [True] --> End
7  --> For Each: User in GetUsersForDigest.List
8       --> SendDigestEmail:
9               UserId = GetUsersForDigest.List.Current.User.Id
10  --> End
11
12Exception Handler (AllExceptions)
13  --> LogError:
14        ModuleName = "HRModule"
15        Source     = "ProcessDailyDigest"
16        Message    = "Timer failed: " + ExceptionMessage
17  --> End

Sometimes you need to run a timer immediately rather than waiting for its scheduled time — for example, after a bulk import completes, trigger the processing timer right away. The Wake<TimerName> system action schedules the timer for immediate execution. It is available in Logic tab → System → Timer. To use: in any Server Action where you want to trigger the timer, drag WakeSendDailyDigestEmail (the system action named Wake + your Timer name) from the Toolbox or Logic tab → System into the action flow. Important behaviors: - WakeTimer does NOT run the timer synchronously. It queues it for the platform's timer execution engine. - If the timer is already running, WakeTimer queues a second run after the current one completes. - WakeTimer can be called from Server Actions only (not Client Actions directly — use a Client Action → Server Action → Wake pattern). Example: after bulk data import completes → WakeSendDailyDigestEmail → user sees 'Digest will be sent shortly'

1/* Server Action: TriggerDigestNow */
2Start
3  --> WakeSendDailyDigestEmail  /* System action from Logic tab → System */
4  --> End
5
6/* Client Action that calls it */
7Start
8  --> TriggerDigestNow (Server Action)
9  --> Message: "Digest email has been queued" (Info)
10  --> End

After publishing, navigate to Service Center → Monitoring → Timers. You see: - Timer Name: the timer you created - Next Run: the next scheduled execution time - Last Run: timestamp of the last execution - Status: Success, Error, or Running - Duration: how long the last run took in seconds - Error Message: populated if the last run failed For detailed logs, click the Timer name → History tab. Each execution row is expandable to show the full error stack trace if it failed. For errors in detail: Service Center → Monitoring → Error Logs — timer LogError entries appear here with full context. Performance tuning: if Duration is close to or exceeds the Default Schedule Timeout (20 min default), increase the timeout in the Timer's Properties Panel or optimize the action. Timers that exceed the timeout are killed by the platform.