Add graphs and retention metrics to admin dashboard (#16829)

app/lib/admin/metrics/dimension/software_versions_dimension.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+class Admin::Metrics::Dimension::SoftwareVersionsDimension < Admin::Metrics::Dimension::BaseDimension
+  include Redisable
+
+  def key
+    'software_versions'
+  end
+
+  def data
+    [mastodon_version, ruby_version, postgresql_version, redis_version]
+  end
+
+  private
+
+  def mastodon_version
+    value = Mastodon::Version.to_s
+
+    {
+      key: 'mastodon',
+      human_key: 'Mastodon',
+      value: value,
+      human_value: value,
+    }
+  end
+
+  def ruby_version
+    value = "#{RUBY_VERSION}p#{RUBY_PATCHLEVEL}"
+
+    {
+      key: 'ruby',
+      human_key: 'Ruby',
+      value: value,
+      human_value: value,
+    }
+  end
+
+  def postgresql_version
+    value = ActiveRecord::Base.connection.execute('SELECT VERSION()').first['version'].match(/\A(?:PostgreSQL |)([^\s]+).*\z/)[1]
+
+    {
+      key: 'postgresql',
+      human_key: 'PostgreSQL',
+      value: value,
+      human_value: value,
+    }
+  end
+
+  def redis_version
+    value = redis_info['redis_version']
+
+    {
+      key: 'redis',
+      human_key: 'Redis',
+      value: value,
+      human_value: value,
+    }
+  end
+
+  def redis_info
+    @redis_info ||= begin
+      if redis.is_a?(Redis::Namespace)
+        redis.redis.info
+      else
+        redis.info
+      end
+    end
+  end
+end