Phase 2 Completion Summary

Goal

Add cycle persistence to work_orders table with 5-second throttling

Changes Made

Modified Files

flows.json - Updated "Machine cycles" function node (ID: 0d023d87a13bf56f)

Code Modifications

Machine Cycles Function (/home/mdares/projects/Plastico/flows.json:1180)

Added throttling logic:

Added lastWorkOrderDbWrite global variable to track last DB write timestamp
Implemented 5-second throttle (5000ms) for work_orders persistence
Only sends DB update when timeSinceLastWrite >= 5000
Added debug logging for DB writes

Updated SQL query on 4th output:

UPDATE work_orders
SET cycle_count = ?,
    good_parts = ?,
    progress_percent = ?,
    updated_at = NOW()
WHERE work_order_id = ?

4th Output now sends (when throttle allows):

{
    topic: "UPDATE work_orders SET cycle_count = ?, good_parts = ?, progress_percent = ?, updated_at = NOW() WHERE work_order_id = ?",
    payload: [cycles, produced, progress, activeOrder.id]
}

Wiring Verification

✅ Output 1 (port 0): Scrap prompt → link out + debug ✅ Output 2 (port 1): Production state → multiple consumers ✅ Output 3 (port 2): KPI trigger → multiple consumers ✅ Output 4 (port 3): DB persistence → DB Guard (Cycles) → mariaDB

How It Works

Every machine cycle increments cycleCount and calculates good_parts
On every cycle, check if 5 seconds have passed since last DB write
If yes:
- Send UPDATE message on output 4
- Set lastWorkOrderDbWrite to current timestamp
- Log the DB write operation
If no:
- Send null on output 4 (no DB write)

Data Loss Prevention

Maximum data loss on crash: 5 seconds of cycles (typically 1-2 cycles depending on cycle time)
Balances between:
- Data persistence (resume work orders)
- Database load (not writing every 3-15 second cycle)
- Recovery granularity (acceptable for manufacturing use case)

Backup Created

flows.json.backup_phase2_20251129_055629

Risk Assessment

Risk Level: LOW

Only adds throttled writes to existing logic
Doesn't modify existing UI or state management
Default values (0) won't break existing work orders
DB writes use parameterized queries (SQL injection safe)

Dependencies Met

✅ Phase 1 complete (schema has cycle_count, good_parts columns) ✅ Existing 4th output wiring to DB Guard intact ✅ MariaDB node configured and connected

Next Steps

Ready for Phase 3: Implement Resume/Restart prompt on Load

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