Reconfigure legacy vagrant to utilize hclog

lib/vagrant.rb

@@ -88,7 +88,7 @@ if ENV["VAGRANT_LOG"] && ENV["VAGRANT_LOG"] != ""
 
     logger = VagrantLogger.new("vagrant")
     if ENV["VAGRANT_LOG_FILE"] && ENV["VAGRANT_LOG_FILE"] != ""
-      logger.outputters = Log4r::FileOutputter.new("vagrant", {:filename=>ENV["VAGRANT_LOG_FILE"]} )
+      logger.outputters = Log4r::FileOutputter.new("vagrant", filename: ENV["VAGRANT_LOG_FILE"])
     else
       logger.outputters = Log4r::Outputter.stderr
     end

lib/vagrant/shared_helpers.rb

@@ -236,6 +236,11 @@ module Vagrant
   def self.enable_server_mode!
     if !server_mode?
       SERVER_MODE_CALLBACKS.each(&:call)
+      l = VagrantLogger.new("")
+      lv = VagrantLogger.new("vagrant")
+      l.outputters = Log4r::Outputter.stderr
+      lv.outputters = Log4r::Outputter.stderr
+      Log4r::Outputter.stderr.formatter = Util::HCLogFormatter.new
     end
     @_server_mode = true
   end

lib/vagrant/util.rb

@@ -18,6 +18,7 @@ module Vagrant
     autoload :GuestHosts,                'vagrant/util/guest_hosts'
     autoload :GuestInspection,           'vagrant/util/guest_inspection'
     autoload :HashWithIndifferentAccess, 'vagrant/util/hash_with_indifferent_access'
+    autoload :HCLogFormatter,            'vagrant/util/logging_formatter'
     autoload :InstallShellConfig,        'vagrant/util/install_cli_autocomplete'
     autoload :InstallZSHShellConfig,     'vagrant/util/install_cli_autocomplete'
     autoload :InstallBashShellConfig,    'vagrant/util/install_cli_autocomplete'

lib/vagrant/util/logging_formatter.rb

@@ -24,5 +24,19 @@ module Vagrant
         CredentialScrubber.desensitize(msg)
       end
     end
+
+    class HCLogFormatter < Log4r::BasicFormatter
+      def format(event)
+        d = {
+          "@timestamp" => Time.now.strftime("%Y-%m-%dT%H:%M:%S.%6N%:z"),
+          "@level" => Log4r::LNAMES[event.level].downcase,
+          "@module" => event.fullname.gsub("::", "."),
+          "@message" => format_object(event.data),
+        }
+        d["@caller"] = event.tracer[0] if event.tracer
+
+        d.to_json + "\n"
+      end
+    end
   end
 end