feat(job): allow passing debounce as option

docs/gitbook/SUMMARY.md

@@ -30,6 +30,7 @@
   * [LIFO](guide/jobs/lifo.md)
   * [Job Ids](guide/jobs/job-ids.md)
   * [Job Data](guide/jobs/job-data.md)
+  * [Debouncing](guide/jobs/debouncing.md)
   * [Delayed](guide/jobs/delayed.md)
   * [Repeatable](guide/jobs/repeatable.md)
   * [Prioritized](guide/jobs/prioritized.md)

docs/gitbook/guide/jobs/debouncing.md

@@ -0,0 +1,49 @@
+# Debouncing
+
+Debouncing in BullMQ is a process where job execution is delayed and deduplicated based on specific identifiers. It ensures that within a specified period, or until a specific job is completed or failed, no new jobs with the same identifier will be added to the queue. Instead, these attempts will trigger a debounced event.
+
+## Fixed Mode
+
+In the Fixed Mode, debouncing works by assigning a delay (Time to Live, TTL) to a job upon its creation. If a similar job (identified by a unique debouncer ID) is added during this delay period, it is ignored. This prevents the queue from being overwhelmed with multiple instances of the same task, thus optimizing the processing time and resource utilization.
+
+```typescript
+import { Queue } from 'bullmq';
+
+const myQueue = new Queue('Paint');
+
+// Add a job that will be debounced for 5 seconds.
+await myQueue.add(
+  'house',
+  { color: 'white' },
+  { debounce: { id: 'customValue', ttl: 5000 } },
+);
+```
+
+In this example, after adding the house painting job with the debouncing parameters (id and ttl), any subsequent job with the same debouncing ID customValue added within 5 seconds will be ignored. This is useful for scenarios where rapid, repetitive requests are made, such as multiple users or processes attempting to trigger the same job.
+
+Note that you must provide a debounce id that should represent your job. You can hash your entire job data or a subset of attributes for creating this identifier.
+
+## Extended Mode
+
+The Extended Mode takes a different approach by extending the debouncing duration until the job's completion or failure. This means as long as the job remains in an incomplete state (neither succeeded nor failed), any subsequent job with the same debouncer ID will be ignored.
+
+```typescript
+// Add a job that will be debounced as this record is not finished (completed or failed).
+await myQueue.add(
+  'house',
+  { color: 'white' },
+  { debounce: { id: 'customValue' } },
+);
+```
+
+While this job is not moved to completed or failed state, next jobs added with same **debounce id** will be ignored and a _debounced_ event will be triggered by our QueueEvent class.
+
+This mode is particularly useful for jobs that have a long running time or those that must not be duplicated until they are resolved, such as processing a file upload or performing a critical update that should not be repeated if the initial attempt is still in progress.
+
+{% hint style="warning" %}
+Any manual deletion will disable the debouncing. For example, when calling _job.remove_ method.
+{% endhint %}
+
+## Read more:
+
+- 💡 [Add Job API Reference](https://api.docs.bullmq.io/classes/v5.Queue.html#add)

src/classes/job.ts

@@ -38,6 +38,7 @@ import type { QueueEvents } from './queue-events';
 const logger = debuglog('bull');
 
 const optsDecodeMap = {
+  de: 'debounce',
   fpof: 'failParentOnFailure',
   idof: 'ignoreDependencyOnFailure',
   kl: 'keepLogs',
@@ -136,6 +137,11 @@ export class Job<
    */
   parent?: ParentKeys;
 
+  /**
+   * Debounce identifier.
+   */
+  debounceId?: string;
+
   /**
    * Base repeat job key.
    */
@@ -199,6 +205,8 @@ export class Job<
       ? { id: opts.parent.id, queueKey: opts.parent.queue }
       : undefined;
 
+    this.debounceId = opts.debounce ? opts.debounce.id : undefined;
+
     this.toKey = queue.toKey.bind(queue);
     this.setScripts();
 
@@ -322,6 +330,10 @@ export class Job<
       job.repeatJobKey = json.rjk;
     }
 
+    if (json.deid) {
+      job.debounceId = json.deid;
+    }
+
     job.failedReason = json.failedReason;
 
     job.attemptsStarted = parseInt(json.ats || '0');
@@ -445,6 +457,7 @@ export class Job<
       timestamp: this.timestamp,
       failedReason: JSON.stringify(this.failedReason),
       stacktrace: JSON.stringify(this.stacktrace),
+      debounceId: this.debounceId,
       repeatJobKey: this.repeatJobKey,
       returnvalue: JSON.stringify(this.returnvalue),
     };

src/classes/queue-events.ts

@@ -45,6 +45,13 @@ export interface QueueEventsListener extends IoredisListener {
     id: string,
   ) => void;
 
+  /**
+   * Listen to 'debounced' event.
+   *
+   * This event is triggered when a job is debounced because debouncedId still existed.
+   */
+  debounced: (args: { jobId: string }, id: string) => void;
+
   /**
    * Listen to 'delayed' event.
    *

src/classes/queue-keys.ts

@@ -24,6 +24,7 @@ export class QueueKeys {
       'events',
       'pc', // priority counter key
       'marker', // marker key
+      'de', // debounce key
     ].forEach(key => {
       keys[key] = this.toKey(name, key);
     });

src/classes/queue.ts

@@ -187,10 +187,10 @@ export class Queue<
    * Get global concurrency value.
    * Returns null in case no value is set.
    */
-  async getGlobalConcurrency():Promise<number|null> {
+  async getGlobalConcurrency(): Promise<number | null> {
     const client = await this.client;
     const concurrency = await client.hget(this.keys.meta, 'concurrency');
-    if(concurrency){
+    if (concurrency) {
       return Number(concurrency);
     }
     return null;
@@ -203,12 +203,11 @@ export class Queue<
    * is processed at any given time. If this limit is not defined, there will be no
    * restriction on the number of concurrent jobs.
    */
-    async setGlobalConcurrency(concurrency: number) {
-      const client = await this.client;
-      return client.hset(this.keys.meta, 'concurrency', concurrency);
-    }
-
-
+  async setGlobalConcurrency(concurrency: number) {
+    const client = await this.client;
+    return client.hset(this.keys.meta, 'concurrency', concurrency);
+  }
+
   /**
    * Adds a new job to the queue.
    *
@@ -374,6 +373,17 @@ export class Queue<
     return !removed;
   }
 
+  /**
+   * Removes a debounce key.
+   *
+   * @param id - identifier
+   */
+  async removeDebounceKey(id: string): Promise<number> {
+    const client = await this.client;
+
+    return client.del(`${this.keys.de}:${id}`);
+  }
+
   /**
    * Removes a repeatable job by its key. Note that the key is the one used
    * to store the repeatable job metadata and not one of the job iterations

src/classes/scripts.ts

@@ -183,6 +183,7 @@ export class Scripts {
       parentOpts.parentDependenciesKey || null,
       parent,
       job.repeatJobKey,
+      job.debounceId ? `${queueKeys.de}:${job.debounceId}` : null,
     ];
 
     let encodedOpts;

src/commands/addDelayedJob-6.lua

@@ -25,6 +25,7 @@
             [7]  parent dependencies key.
             [8]  parent? {id, queueKey}
             [9]  repeat job key
+            [10] debounce key
 
       ARGV[2] Json stringified job data
       ARGV[3] msgpacked options
@@ -49,12 +50,14 @@ local args = cmsgpack.unpack(ARGV[1])
 local data = ARGV[2]
 
 local parentKey = args[5]
-local repeatJobKey = args[9]
 local parent = args[8]
+local repeatJobKey = args[9]
+local debounceKey = args[10]
 local parentData
 
 -- Includes
 --- @include "includes/addDelayMarkerIfNeeded"
+--- @include "includes/debounceJob"
 --- @include "includes/getDelayedScore"
 --- @include "includes/getOrSetMaxEvents"
 --- @include "includes/handleDuplicatedJob"
@@ -73,6 +76,7 @@ local opts = cmsgpack.unpack(ARGV[3])
 
 local parentDependenciesKey = args[7]
 local timestamp = args[4]
+
 if args[2] == "" then
     jobId = jobCounter
     jobIdKey = args[1] .. jobId
@@ -86,6 +90,12 @@ else
     end
 end
 
+local debouncedJobId = debounceJob(args[1], opts['de'],
+  jobId, debounceKey, eventsKey, maxEvents)
+if debouncedJobId then
+  return debouncedJobId
+end
+
 -- Store the job.
 local delay, priority = storeJob(eventsKey, jobIdKey, jobId, args[3], ARGV[2],
                                  opts, timestamp, parentKey, parentData,

src/commands/addParentJob-4.lua

@@ -20,6 +20,7 @@
             [7]  parent dependencies key.
             [8]  parent? {id, queueKey}
             [9]  repeat job key
+            [10] debounce key
 
       ARGV[2] Json stringified job data
       ARGV[3] msgpacked options
@@ -44,11 +45,13 @@ local data = ARGV[2]
 local opts = cmsgpack.unpack(ARGV[3])
 
 local parentKey = args[5]
-local repeatJobKey = args[9]
 local parent = args[8]
+local repeatJobKey = args[9]
+local debounceKey = args[10]
 local parentData
 
 -- Includes
+--- @include "includes/debounceJob"
 --- @include "includes/getOrSetMaxEvents"
 --- @include "includes/handleDuplicatedJob"
 --- @include "includes/storeJob"
@@ -78,6 +81,12 @@ else
     end
 end
 
+local debouncedJobId = debounceJob(args[1], opts['de'],
+  jobId, debounceKey, eventsKey, maxEvents)
+if debouncedJobId then
+  return debouncedJobId
+end
+
 -- Store the job.
 storeJob(eventsKey, jobIdKey, jobId, args[3], ARGV[2], opts, timestamp,
          parentKey, parentData, repeatJobKey)

src/commands/addPrioritizedJob-8.lua

@@ -24,7 +24,8 @@
             [7]  parent dependencies key.
             [8]  parent? {id, queueKey}
             [9]  repeat job key
-
+            [10] debounce key
+
       ARGV[2] Json stringified job data
       ARGV[3] msgpacked options
 
@@ -51,12 +52,14 @@ local data = ARGV[2]
 local opts = cmsgpack.unpack(ARGV[3])
 
 local parentKey = args[5]
-local repeatJobKey = args[9]
 local parent = args[8]
+local repeatJobKey = args[9]
+local debounceKey = args[10]
 local parentData
 
 -- Includes
 --- @include "includes/addJobWithPriority"
+--- @include "includes/debounceJob"
 --- @include "includes/storeJob"
 --- @include "includes/getOrSetMaxEvents"
 --- @include "includes/handleDuplicatedJob"
@@ -87,6 +90,12 @@ else
     end
 end
 
+local debouncedJobId = debounceJob(args[1], opts['de'],
+  jobId, debounceKey, eventsKey, maxEvents)
+if debouncedJobId then
+  return debouncedJobId
+end
+
 -- Store the job.
 local delay, priority = storeJob(eventsKey, jobIdKey, jobId, args[3], ARGV[2],
                                  opts, timestamp, parentKey, parentData,

src/commands/addStandardJob-8.lua

@@ -34,7 +34,8 @@
             [7]  parent dependencies key.
             [8]  parent? {id, queueKey}
             [9]  repeat job key
-
+            [10] debounce key
+
       ARGV[2] Json stringified job data
       ARGV[3] msgpacked options
 
@@ -54,12 +55,14 @@ local data = ARGV[2]
 local opts = cmsgpack.unpack(ARGV[3])
 
 local parentKey = args[5]
-local repeatJobKey = args[9]
 local parent = args[8]
+local repeatJobKey = args[9]
+local debounceKey = args[10]
 local parentData
 
 -- Includes
 --- @include "includes/addJobInTargetList"
+--- @include "includes/debounceJob"
 --- @include "includes/getOrSetMaxEvents"
 --- @include "includes/getTargetQueueList"
 --- @include "includes/handleDuplicatedJob"
@@ -91,6 +94,12 @@ else
     end
 end
 
+local debouncedJobId = debounceJob(args[1], opts['de'],
+  jobId, debounceKey, eventsKey, maxEvents)
+if debouncedJobId then
+  return debouncedJobId
+end
+
 -- Store the job.
 storeJob(eventsKey, jobIdKey, jobId, args[3], ARGV[2], opts, timestamp,
          parentKey, parentData, repeatJobKey)

src/commands/includes/cleanList.lua

@@ -34,7 +34,7 @@ local function cleanList(listKey, jobKeyPrefix, rangeStart, rangeEnd,
         -- replace the entry with a deletion marker; the actual deletion will
         -- occur at the end of the script
         rcall("LSET", listKey, rangeEnd - jobIdsLen + i, deletionMarker)
-        removeJob(job, true, jobKeyPrefix)
+        removeJob(job, true, jobKeyPrefix, true --[[remove debounce key]])
         deletedCount = deletedCount + 1
         table.insert(deleted, job)
       end

src/commands/includes/cleanSet.lua

@@ -21,14 +21,14 @@ local function cleanSet(setKey, jobKeyPrefix, rangeEnd, timestamp, limit, attrib
 
     local jobKey = jobKeyPrefix .. job
     if isFinished then
-      removeJob(job, true, jobKeyPrefix)
+      removeJob(job, true, jobKeyPrefix, true --[[remove debounce key]])
       deletedCount = deletedCount + 1
       table.insert(deleted, job)
     else
       -- * finishedOn says when the job was completed, but it isn't set unless the job has actually completed
       jobTS = getTimestamp(jobKey, attributes)
       if (not jobTS or jobTS <= timestamp) then
-        removeJob(job, true, jobKeyPrefix)
+        removeJob(job, true, jobKeyPrefix, true --[[remove debounce key]])
         deletedCount = deletedCount + 1
         table.insert(deleted, job)
       end

src/commands/includes/debounceJob.lua

@@ -0,0 +1,23 @@
+--[[
+  Function to debounce a job.
+]]
+
+local function debounceJob(prefixKey, debounceOpts, jobId, debounceKey, eventsKey, maxEvents)
+  local debounceId = debounceOpts and debounceOpts['id']
+  if debounceId then
+    local ttl = debounceOpts['ttl']
+    local debounceKeyExists
+    if ttl then
+      debounceKeyExists = not rcall('SET', debounceKey, jobId, 'PX', ttl, 'NX')
+    else
+      debounceKeyExists = not rcall('SET', debounceKey, jobId, 'NX')
+    end
+    if debounceKeyExists then
+      local currentDebounceJobId = rcall('GET', debounceKey)
+      rcall("XADD", eventsKey, "MAXLEN", "~", maxEvents, "*", "event",
+        "debounced", "jobId", currentDebounceJobId)
+      return currentDebounceJobId
+    end
+  end
+end
+