How to Share Data Between Measures in OpenStudio

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The server has implemented an Extended Runner class which automates the process of persisting measures and their argument values across a datapoint. The class is implemented here. The following command inside the run method of a measure returns a hash of previous measures and their arguments:

runner.former_workflow_arguments

An example of this hash, saved as a json, is as follows:

{ "set_dr_weather_file":{"weather_directory_name":"weather","weather_file_name":"USA_CO_Denver.Intl.AP.725650_TMY3.epw"}, "idf_reference_building_selector":{"building_type":"Stand-aloneRetailNew2004"}, "set_timestep":{"timestep":"60"}, "hardsize_dx_coil":{"cfm_per_ton":"370","square_foot_per_ton":"350"} }

This functionality is currently in the EnergyPlus-8.3.0 branch of the Workflow Gem, and has not yet been released on rubygems. To use it ensure your Gemfile has the following line in it:

gem "openstudio-workflow", :github => "NREL/OpenStudio-workflow-gem", :branch => 'EnergyPlus-8.3.0'

Finally, run bundle update and bundle install from the command line to set your openstudio-workflow gem to the E+ 8.3.0 branch of github.

You can also have each measure write its own file and have the other measures read it. For this to work on both PAT( OS-app) and the OS-server, the following directories should work:

 json_path = '../OtherMeasureDirectoryName/results.json'  #this is the path structure on the server
if File.exist? ems_path
  ems_string = File.read(ems_path)
  if File.exist? json_path
    json = JSON.parse(File.read(json_path))
  end
else
  json_path2 = Dir.glob('../../**/results.json')  #this will parse the directory structure with PAT/OS-app
  json_path1 = json_path2[0]
  if File.exist? json_path
    json = JSON.parse(File.read(json_path))
  end

end

This will probably change next year once OS-server and OS-App use the same workflow manager, but this is a way off.

When we needed this with OpenStudio server we created a file named "resource.json" in the lib directory. We made a helper method to read and write to this file that measures had access to. This allowed us to pass information across measures. On OpenStudio server we use a relative path to the resource file. For a local run with OS app or PAT you might need an absolute path, but I haven't tested this.

You can file a user voice request to allow direct access to log messages from earlier measures in the workflow.