Sendinblue email balancing using interceptor

Signed-off-by: Chaïb Martinez <chaibax@gmail.com>

app/models/dynamic_smtp_settings_interceptor.rb

@@ -0,0 +1,16 @@
+class DynamicSmtpSettingsInterceptor
+  def self.delivering_email(message)
+    if ENV['SENDINBLUE_BALANCING'] == 'enabled'
+      if rand(0..99) < ENV['SENDINBLUE_BALANCING_VALUE'].to_i
+        message.delivery_method.settings = {
+          user_name: ENV['SENDINBLUE_USER_NAME'],
+          password: ENV['SENDINBLUE_CLIENT_KEY'],
+          address: 'smtp-relay.sendinblue.com',
+          domain: 'smtp-relay.sendinblue.com',
+          port: '587',
+          authentication: :cram_md5
+        }
+      end
+    end
+  end
+end

config/env.example

@@ -46,8 +46,13 @@ SENTRY_DSN_JS=""
 MATOMO_ENABLED="disabled"
 MATOMO_ID="73"
 
-SENDINBLUE_ENABLED="disabled"
+SENDINBLUE_BALANCING=""
+SENDINBLUE_BALANCING_VALUE=""
+SENDINBLUE_ENABLED=""
 SENDINBLUE_CLIENT_KEY=""
+SENDINBLUE_USER_NAME=""
+
+
 CRISP_ENABLED="disabled"
 CRISP_CLIENT_KEY=""
 

config/environments/development.rb

@@ -45,14 +45,26 @@ Rails.application.configure do
   config.assets.raise_runtime_errors = true
 
   # Action Mailer settings
-  config.action_mailer.delivery_method = :letter_opener_web
+
-  # Configure default root URL for generating URLs to routes
+  if ENV['SENDINBLUE_ENABLED'] == 'enabled'
-  config.action_mailer.default_url_options = {
+    config.action_mailer.delivery_method = :smtp
-    host: 'localhost',
+    config.action_mailer.smtp_settings = {
-    port: 3000
+      user_name: Rails.application.secrets.sendinblue[:username],
-  }
+      password: Rails.application.secrets.sendinblue[:client_key],
-  # Configure default root URL for email assets
+      address: 'smtp-relay.sendinblue.com',
-  config.action_mailer.asset_host = "http://" + ENV['APP_HOST']
+      domain: 'smtp-relay.sendinblue.com',
+      port: '587',
+      authentication: :cram_md5
+    }
+  else
+    config.action_mailer.delivery_method = :letter_opener_web
+    config.action_mailer.default_url_options = {
+      host: 'localhost',
+      port: 3000
+    }
+
+    config.action_mailer.asset_host = "http://" + ENV['APP_HOST']
+  end
 
   Rails.application.routes.default_url_options = {
     host: 'localhost',

config/environments/production.rb

@@ -77,6 +77,16 @@ Rails.application.configure do
       port: '2525',
       authentication: :cram_md5
     }
+  elsif ENV['SENDINBLUE_ENABLED'] == 'enabled'
+    config.action_mailer.delivery_method = :smtp
+    config.action_mailer.smtp_settings = {
+      user_name: Rails.application.secrets.sendinblue[:username],
+      password: Rails.application.secrets.sendinblue[:client_key],
+      address: 'smtp-relay.sendinblue.com',
+      domain: 'smtp-relay.sendinblue.com',
+      port: '587',
+      authentication: :cram_md5
+    }
   else
     config.action_mailer.delivery_method = :mailjet
   end

config/initializers/dynamic_smtp_settings_interceptor.rb

@@ -0,0 +1 @@
+ActionMailer::Base.register_interceptor "DynamicSmtpSettingsInterceptor"

config/secrets.yml

@@ -54,6 +54,7 @@ defaults: &defaults
     webhook_secret: <%= ENV['HELPSCOUT_WEBHOOK_SECRET'] %>
   sendinblue:
     enabled: <%= ENV['SENDINBLUE_ENABLED'] == 'enabled' %>
+    username: <%= ENV['SENDINBLUE_USER_NAME'] %>
     client_key: <%= ENV['SENDINBLUE_CLIENT_KEY'] %>
     api_v3_key: <%= ENV['SENDINBLUE_API_V3_KEY'] %>
   matomo: