feat: schedule scan based on queue events

lib/scan.js

@@ -1,6 +1,7 @@
 import { logger } from './logger.js'
 import { options } from './args.js'
 import { queue as parseQueue} from './parse.js'
+import { cargoQueue } from './cargo.js'
 import { serializeError } from 'serialize-error'
 import fg from 'fast-glob'
 import lineByLine from 'n-readlines'
@@ -11,11 +12,37 @@ const component = 'scan'
 const historySet = new Set() // in memory history set
 let isWriteScheduled = false // flag to indicate if there is pending files to write to the history file
 let timeoutId // id of the active setTimeout
+let isParseQueueActive = false
+let isCargoQueueActive = false
+
+function testScheduleNextScan() {
+  if (!isParseQueueActive && !isCargoQueueActive && !options.oneShot) {
+    scheduleNextScan()
+  }
+}
 
 /**
  * Utility function that calls initHistory() and startScanner()
  */
 function initScanner() {
+  parseQueue.on('task_queued', () => {
+    logger.info({ component, message: `parse_queue_task_queued` })
+    isParseQueueActive = true
+  })
+  parseQueue.on('drain', () => {
+    logger.info({ component, message: `parse_queue_drained` })
+    isParseQueueActive = false
+    testScheduleNextScan()
+  })
+  cargoQueue.on('task_queued', () => {
+    logger.info({ component, message: `cargo_queue_task_queued` })
+    isCargoQueueActive = true
+  })
+  cargoQueue.on('drain', () => {
+    logger.info({ component, message: `cargo_queue_drained` })
+    isCargoQueueActive = false
+    testScheduleNextScan()
+  })
   initHistory()
   startScanner()
   Alarm.on('alarmRaised', onAlarmRaised)
@@ -53,18 +80,11 @@ async function startScanner() {
       //Remove stale files: those in historySet but not found in the current scan
       removeStaleFiles(discoveredFiles)
       logger.info({ component, message: `scan ended`, path: options.path })
+      testScheduleNextScan()
   } 
   catch (e) {
       logger.error({ component, error: serializeError(e) })
   } 
-  finally {
-    if (!options.oneShot) {
-        scheduleNextScan()
-    } 
-    else {
-        logger.info({ component, message: `one-shot scan completed`, path: options.path })
-    }
-  }
 }
 
 /**