refactor: move the imap backoff keys to installation configs

app/models/channel/email.rb

@@ -39,8 +39,6 @@ class Channel::Email < ApplicationRecord
   include Reauthorizable
 
   AUTHORIZATION_ERROR_THRESHOLD = 10
-  IMAP_BACKOFF_MAX_INTERVAL_MINUTES = 5
-  IMAP_BACKOFF_MAX_INTERVAL_COUNT = 5
 
   # TODO: Remove guard once encryption keys become mandatory (target 3-4 releases out).
   if Chatwoot.encryption_configured?
@@ -85,17 +83,14 @@ class Channel::Email < ApplicationRecord
 
   def apply_imap_backoff!
     new_count = imap_retry_count + 1
-    max_retries = (IMAP_BACKOFF_MAX_INTERVAL_MINUTES - 1) + IMAP_BACKOFF_MAX_INTERVAL_COUNT
+    max_retries = imap_backoff_max_retries
 
     if new_count > max_retries
       Rails.logger.warn "Error for email channel - #{inbox.id} exhausted backoff (#{new_count} failures), prompting reauthorization"
       clear_imap_backoff!
       prompt_reauthorization!
     else
-      wait_minutes = [new_count, IMAP_BACKOFF_MAX_INTERVAL_MINUTES].min
-      ::Redis::Alfred.set(imap_retry_count_key, new_count.to_s)
-      ::Redis::Alfred.set(imap_retry_after_key, wait_minutes.minutes.from_now.to_f.to_s)
-      Rails.logger.warn "Error for email channel - #{inbox.id} backoff retry #{new_count}/#{max_retries}, next attempt in #{wait_minutes}m"
+      schedule_imap_retry(new_count, max_retries)
     end
   end
 
@@ -110,6 +105,20 @@ class Channel::Email < ApplicationRecord
     self.forward_to_email ||= "#{SecureRandom.hex}@#{account.inbound_email_domain}"
   end
 
+  def imap_backoff_max_retries
+    max_interval = GlobalConfigService.load('IMAP_BACKOFF_MAX_INTERVAL_MINUTES', 5).to_i
+    max_count = GlobalConfigService.load('IMAP_BACKOFF_MAX_INTERVAL_COUNT', 10).to_i
+    (max_interval - 1) + max_count
+  end
+
+  def schedule_imap_retry(new_count, max_retries)
+    max_interval = GlobalConfigService.load('IMAP_BACKOFF_MAX_INTERVAL_MINUTES', 5).to_i
+    wait_minutes = [new_count, max_interval].min
+    ::Redis::Alfred.set(imap_retry_count_key, new_count.to_s)
+    ::Redis::Alfred.set(imap_retry_after_key, wait_minutes.minutes.from_now.to_f.to_s)
+    Rails.logger.warn "Error for email channel - #{inbox.id} backoff retry #{new_count}/#{max_retries}, next attempt in #{wait_minutes}m"
+  end
+
   def imap_retry_count_key
     format(::Redis::Alfred::IMAP_BACKOFF_RETRY_COUNT, channel_id: id)
   end

app/services/imap/authentication_error.rb

@@ -0,0 +1 @@
+class Imap::AuthenticationError < StandardError; end

config/installation_config.yml

@@ -96,6 +96,19 @@
   locked: false
 # ------- End of Account Related Config ------- #
 
+# ------- IMAP Backoff Related Config ------- #
+- name: IMAP_BACKOFF_MAX_INTERVAL_MINUTES
+  display_title: 'IMAP Backoff Max Interval (minutes)'
+  description: 'Maximum wait time in minutes between IMAP retry attempts before the backoff plateaus'
+  value: 5
+  locked: false
+- name: IMAP_BACKOFF_MAX_INTERVAL_COUNT
+  display_title: 'IMAP Backoff Max Retry Count'
+  description: 'Number of additional retries at the maximum interval before prompting reauthorization'
+  value: 10
+  locked: false
+# ------- End of IMAP Backoff Related Config ------- #
+
 # ------- Email Related Config ------- #
 - name: MAILER_INBOUND_EMAIL_DOMAIN
   display_title: 'Inbound Email Domain'

lib/exception_list.rb

@@ -1,7 +1,5 @@
 require 'net/imap'
 
-class Imap::AuthenticationError < StandardError; end
-
 module ExceptionList
   REST_CLIENT_EXCEPTIONS = [RestClient::NotFound, RestClient::GatewayTimeout, RestClient::BadRequest,
                             RestClient::MethodNotAllowed, RestClient::Forbidden, RestClient::InternalServerError,