Fix key names in statsd

config/initializers/statsd.rb

 # frozen_string_literal: true
+RESERVED_CHARACTERS_REGEX = /[\:\|\@]/
 
 StatsD.prefix              = 'mastodon'
 StatsD.default_sample_rate = 1
 
+def clean_name(str)
+  str.gsub('::', '.').gsub(RESERVED_CHARACTERS_REGEX, '_')
+end
+
 ActiveSupport::Notifications.subscribe(/performance/) do |name, _start, _finish, _id, payload|
   action      = payload[:action] || :increment
   measurement = payload[:measurement]
   value       = payload[:value]
-  key_name    = "#{name}.#{measurement}"
+  key_name    = clean_name("#{name}.#{measurement}")
 
   StatsD.send(action.to_s, key_name, (value || 1))
 end