set smtp opts via settings allowing runtime override

otherwise it's impossible to update
it at runtime/inapp since the merge
of configuration and settings in 12.1

app/models/setting.rb

@@ -157,7 +157,11 @@ class Setting < ApplicationRecord
   end
 
   def value=(val)
-    unless definition.writable?
+    set_value! val
+  end
+
+  def set_value!(val, force: false)
+    unless force || definition.writable?
       raise NoMethodError, "#{name} is not writable but can be set through env vars or configuration.yml file."
     end
 

lib/tasks/setting.rake

@@ -47,4 +47,17 @@ namespace :setting do
       puts(setting.value)
     end
   end
+
+  desc 'Allow to set a Setting read from an ENV var. Example: rake setting:set_to_env[smtp_address=SMTP_HOST]'
+  task set_to_env: :environment do |_t, args|
+    args.extras.each do |tuple|
+      setting_name, env_var_name = tuple.split('=')
+
+      next unless Settings::Definition.exists? setting_name
+      next unless ENV.has_key? env_var_name
+
+      setting = Setting.find_by name: setting_name
+      setting.set_value! ENV[env_var_name].presence, force: true
+    end
+  end
 end

packaging/conf/configuration.yml

@@ -37,15 +37,6 @@
 default:
   rails_cache_store: <%= ENV.fetch('RAILS_CACHE_STORE') { :memcache }.to_sym %>
   session_store: <%= ENV.fetch('SESSION_STORE') { :active_record_store }.to_sym %>
-  email_delivery_method: <%= ENV.fetch('EMAIL_DELIVERY_METHOD') { :sendmail } %>
-  smtp_address: <%= ENV['SMTP_HOST'] %>
-  smtp_port: <%= ENV.fetch('SMTP_PORT') { 25 }.to_i %>
-  smtp_domain: <%= ENV.fetch('SMTP_DOMAIN') { ENV['HOSTNAME'] } %>
-  smtp_authentication: <%= ENV.fetch('SMTP_AUTHENTICATION') { :login }.to_sym %>
-  smtp_user_name: <%= ENV['SMTP_USERNAME'] %>
-  smtp_password: <%= ENV['SMTP_PASSWORD'] %>
-  smtp_enable_starttls_auto: <%= ENV.fetch('SMTP_ENABLE_STARTTLS_AUTO') { "false" } %>
-  smtp_ssl: <%= ENV.fetch('SMTP_SSL') { "false" } %>
   attachments_storage_path: <%= ENV.fetch('ATTACHMENTS_STORAGE_PATH') { "/var/db/_APP_NAME_/files" } %>
 <% git_configured = ENV['GIT_REPOSITORIES'].present? %>
 <% svn_configured = ENV['SVN_REPOSITORIES'].present? %>

packaging/scripts/postinstall

@@ -0,0 +1,37 @@
+#!/bin/bash -e
+
+# Apply SMTP options given in the packager wizard to the settings within
+# the database. This will override existing settings.
+# The user can just choose `skip` during `reconfigure` if they do not want that.
+
+if [ "$EMAIL_DELIVERY_METHOD" = "smtp" ]; then
+  ${CLI} run rake "setting:set_to_env[\
+email_delivery_method=EMAIL_DELIVERY_METHOD,\
+smtp_authentication=SMTP_AUTHENTICATION,\
+smtp_address=SMTP_HOST,\
+smtp_port=SMTP_PORT,\
+smtp_user_name=SMTP_USERNAME,\
+smtp_password=SMTP_PASSWORD,\
+smtp_domain=SMTP_DOMAIN\
+]"
+elif [ "$EMAIL_DELIVERY_METHOD" = "sendmail" ]; then
+  ${CLI} run rake "setting:set[email_delivery_method=sendmail]"
+fi
+
+# We have transferred all the SMTP options to their settings within the database.
+# Next we remove them from the env. This way they don't pin the settings to the
+# env values allowing users to still change the SMTP options at runtime.
+
+# This only removes env vars generated by packager.
+# If an admin still wants to pin a certain setting to a given value they can still do
+# so by using the prefixed setting names. For instance:
+#
+#  openproject config:set OPENPROJECT_SMTP__PORT=42
+
+${CLI} config:unset EMAIL_DELIVERY_METHOD
+${CLI} config:unset SMTP_AUTHENTICATION
+${CLI} config:unset SMTP_HOST
+${CLI} config:unset SMTP_PORT
+${CLI} config:unset SMTP_USERNAME
+${CLI} config:unset SMTP_PASSWORD
+${CLI} config:unset SMTP_DOMAIN