Better overrides for database values

Before this change, it was impossible to override certain
gitlab_rails['db_xxx'] settings from gitlab.rb when Postgres was enabled: we
did a hash merge in recipes/gitlab-rails.rb and recipes/gitlab-ci.rb that would
stomp on the custom settings in gitlab.rb. This change makes sure gitlab.rb
overrides for gitlab_XXX['db_YYY'] always win.

files/gitlab-cookbooks/gitlab/libraries/gitlab.rb

@@ -177,6 +177,33 @@ module Gitlab
       end
     end
 
+    def parse_postgresql_settings
+      # If the user wants to run the internal Postgres service using an alternative
+      # DB username, host or port, then those settings should also be applied to
+      # gitlab-rails and gitlab-ci.
+      [
+        # %w{gitlab_rails db_username} corresponds to
+        # Gitlab['gitlab_rails']['db_username'], etc.
+        [%w{gitlab_rails db_username}, %w{postgresql sql_user}],
+        [%w{gitlab_rails db_host}, %w{postgresql listen_address}],
+        [%w{gitlab_rails db_port}, %w{postgresql port}],
+        [%w{gitlab_ci db_username}, %w{postgresql sql_ci_user}],
+        [%w{gitlab_ci db_host}, %w{postgresql listen_address}],
+        [%w{gitlab_ci db_port}, %w{postgresql port}],
+      ].each do |left, right|
+        if ! Gitlab[left.first][left.last].nil?
+          # If the user explicitly sets a value for e.g.
+          # gitlab_rails['db_port'] in gitlab.rb then we should never override
+          # that.
+          next
+        end
+
+        better_value_from_gitlab_rb = Gitlab[right.first][right.last] 
+        default_from_attributes = node['gitlab'][right.first.gsub('_', '-')][right.last]
+        Gitlab[left.first][left.last] = better_value_from_gitlab_rb || default_from_attributes
+      end
+    end
+
     def parse_nginx_listen_address
       return unless nginx['listen_address']
 
@@ -263,6 +290,7 @@ module Gitlab
       parse_git_data_dir
       parse_udp_log_shipping
       parse_redis_settings
+      parse_postgresql_settings
       parse_nginx_listen_address
       # Parse ci_external_url _before_ gitlab_ci settings so that the user
       # can turn on gitlab_ci by only specifying ci_external_url

files/gitlab-cookbooks/gitlab/recipes/gitlab-ci.rb

@@ -81,23 +81,13 @@ template_symlink File.join(gitlab_ci_etc_dir, "secret") do
   restarts dependent_services
 end
 
-database_attributes = node['gitlab']['gitlab-ci'].to_hash
-if node['gitlab']['postgresql']['enable']
-  database_attributes.merge!(
-    :db_adapter => "postgresql",
-    :db_username => node['gitlab']['postgresql']['sql_ci_user'],
-    :db_host => node['gitlab']['postgresql']['listen_address'],
-    :db_port => node['gitlab']['postgresql']['port']
-  )
-end
-
 template_symlink File.join(gitlab_ci_etc_dir, "database.yml") do
   link_from File.join(gitlab_ci_source_dir, "config/database.yml")
   source "database.yml.erb"
   owner "root"
   group "root"
   mode "0644"
-  variables database_attributes
+  variables node['gitlab']['gitlab-ci'].to_hash
   helpers SingleQuoteHelper
   restarts dependent_services
 end

files/gitlab-cookbooks/gitlab/recipes/gitlab-rails.rb

@@ -79,23 +79,13 @@ template_symlink File.join(gitlab_rails_etc_dir, "secret") do
   restarts dependent_services
 end
 
-database_attributes = node['gitlab']['gitlab-rails'].to_hash
-if node['gitlab']['postgresql']['enable']
-  database_attributes.merge!(
-    :db_adapter => "postgresql",
-    :db_username => node['gitlab']['postgresql']['sql_user'],
-    :db_host => node['gitlab']['postgresql']['listen_address'],
-    :db_port => node['gitlab']['postgresql']['port']
-  )
-end
-
 template_symlink File.join(gitlab_rails_etc_dir, "database.yml") do
   link_from File.join(gitlab_rails_source_dir, "config/database.yml")
   source "database.yml.erb"
   owner "root"
   group "root"
   mode "0644"
-  variables database_attributes
+  variables node['gitlab']['gitlab-rails'].to_hash
   helpers SingleQuoteHelper
   restarts dependent_services
 end