fix: Add delay to instagram/messenger echo events to prevent duplicate messages (#12032)

- Add 2-second delay to Facebook Messenger echo event processing to
prevent race condition
- Add 2-second delay to Instagram echo event processing for consistency
- Prevent duplicate messages when echo events arrive before send message
API completes processing

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/controllers/webhooks/instagram_controller.rb

@@ -4,7 +4,16 @@ class Webhooks::InstagramController < ActionController::API
   def events
     Rails.logger.info('Instagram webhook received events')
     if params['object'].casecmp('instagram').zero?
-      ::Webhooks::InstagramEventsJob.perform_later(params.to_unsafe_hash[:entry])
+      entry_params = params.to_unsafe_hash[:entry]
+
+      if contains_echo_event?(entry_params)
+        # Add delay to prevent race condition where echo arrives before send message API completes
+        # This avoids duplicate messages when echo comes early during API processing
+        ::Webhooks::InstagramEventsJob.set(wait: 2.seconds).perform_later(entry_params)
+      else
+        ::Webhooks::InstagramEventsJob.perform_later(entry_params)
+      end
+
       render json: :ok
     else
       Rails.logger.warn("Message is not received from the instagram webhook event: #{params['object']}")
@@ -14,6 +23,16 @@ class Webhooks::InstagramController < ActionController::API
 
   private
 
+  def contains_echo_event?(entry_params)
+    return false unless entry_params.is_a?(Array)
+
+    entry_params.any? do |entry|
+      # Check messaging array for echo events
+      messaging_events = entry[:messaging] || []
+      messaging_events.any? { |messaging| messaging.dig(:message, :is_echo).present? }
+    end
+  end
+
   def valid_token?(token)
     # Validates against both IG_VERIFY_TOKEN (Instagram channel via Facebook page) and
     # INSTAGRAM_VERIFY_TOKEN (Instagram channel via direct Instagram login)

config/initializers/facebook_messenger.rb

@@ -39,6 +39,8 @@ Rails.application.reloader.to_prepare do
   end
 
   Facebook::Messenger::Bot.on :message_echo do |message|
-    Webhooks::FacebookEventsJob.perform_later(message.to_json)
+    # Add delay to prevent race condition where echo arrives before send message API completes
+    # This avoids duplicate messages when echo comes early during API processing
+    Webhooks::FacebookEventsJob.set(wait: 2.seconds).perform_later(message.to_json)
   end
 end

spec/controllers/webhooks/instagram_controller_spec.rb

@@ -33,5 +33,21 @@ RSpec.describe 'Webhooks::InstagramController', type: :request do
       post '/webhooks/instagram', params: instagram_params
       expect(response).to have_http_status(:success)
     end
+
+    context 'when processing echo events' do
+      let!(:echo_params) { build(:instagram_story_mention_event_with_echo).with_indifferent_access }
+
+      it 'delays processing for echo events by 2 seconds' do
+        job_double = class_double(Webhooks::InstagramEventsJob)
+        allow(Webhooks::InstagramEventsJob).to receive(:set).with(wait: 2.seconds).and_return(job_double)
+        allow(job_double).to receive(:perform_later)
+
+        instagram_params = echo_params.merge(object: 'instagram')
+        post '/webhooks/instagram', params: instagram_params
+        expect(response).to have_http_status(:success)
+        expect(Webhooks::InstagramEventsJob).to have_received(:set).with(wait: 2.seconds)
+        expect(job_double).to have_received(:perform_later)
+      end
+    end
   end
 end