Module: PythonWorkflow

Defined in:
lib/scout/workflow/python.rb,
lib/scout/workflow/python/task.rb,
lib/scout/workflow/python/inputs.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#python_task_dir ⇒ Object

Returns the value of attribute python_task_dir.



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# File 'lib/scout/workflow/python.rb', line 9

def python_task_dir
  @python_task_dir
end

Class Method Details

.build_python_argv(py_params, values) ⇒ Object 



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# File 'lib/scout/workflow/python/inputs.rb', line 2

def self.build_python_argv(py_params, values)
  argv = []
  py_params.each do |p|
    name = p['name']
    ptype = p['type']
    default = p['default']
    required = p['required']
    val = values[name]

    if val.nil?
      next unless required
      next
    end

    flag = "--#{name}"
    if ptype.start_with?('list[')
      # Accept several input formats for lists:
      # - Ruby Array
      # - Comma-separated string: "a,b,c"
      # - Path to a file: "file.txt" -> read lines
      items = []
      if val.is_a?(String)
        # If file exists, read lines
        if File.exist?(val)
          items = File.readlines(val, chomp: true)
        elsif val.include?(',')
          items = val.split(',').map(&:strip)
        else
          items = [val]
        end
      elsif val.respond_to?(:to_ary)
        items = Array(val).map(&:to_s)
      else
        items = [val.to_s]
      end

      # pass flag once followed by all items (argparse with nargs='+' expects this)
      argv << flag
      items.each do |x|
        argv << x.to_s
      end
    elsif ptype == 'boolean'
      if default == true
        argv << "--no-#{name}" unless val
      else
        argv << flag if val
      end
    else
      # For scalar inputs: if given a file path and the file exists, pass the path
      # as-is (the Python side can decide how to handle it). Keep quoting to
      # preserve spaces when later shell-joining.
      argv << flag
      argv << val.to_s
    end
  end
  argv
end

.map_param(p) ⇒ Object 



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# File 'lib/scout/workflow/python/task.rb', line 29

def self.map_param(p)
  desc = p['help'] || ""
  default = p['default']
  required = p['required'] ? true : false

  ruby_type =
    case p['type']
    when 'string' then :string
    when 'integer' then :integer
    when 'float'   then :float
    when 'boolean' then :boolean
    when 'binary'  then :binary
    when 'path'    then :file
    else
      if p['type'].start_with?('list[')
        subtype = p['type'][5..-2]
        ruby_sub = case subtype
                   when 'path' then :file_array
                   else :array
                   end
        ruby_sub
      else
        :string
      end
    end

  options = {}
  options[:required] = true if required

  { name: p['name'], type: ruby_type, desc: desc, default: default, options: options }
end

.map_returns(py_type) ⇒ Object 



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# File 'lib/scout/workflow/python/task.rb', line 11

def self.map_returns(py_type)
  case py_type
  when 'string' then :string
  when 'integer' then :integer
  when 'float' then :float
  when 'boolean' then :boolean
  when 'binary' then :binary
  when 'path' then :string
  when 'list', 'array' then :array
  else
    if py_type.start_with?("list[")
      :array
    else
      :string
    end
  end
end

.read_python_metadata(file) ⇒ Object 



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# File 'lib/scout/workflow/python/task.rb', line 5

def self.read_python_metadata(file)
  out = ScoutPython.run_file file, '--scout-metadata'
  raise "Error getting metadata from #{file}: #{err}" unless out.exit_status == 0
  JSON.parse(out.read)
end

Instance Method Details

#python_task(task_sym, file: nil, returns: nil, extension: nil, desc: nil) ⇒ Object 



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# File 'lib/scout/workflow/python/task.rb', line 61

def python_task(task_sym, file: nil, returns: nil, extension: nil, desc: nil)
  name = task_sym.to_s
  file ||= python_task_dir[name].find_with_extension('py')
  raise "Python task file not found: #{file}" unless File.exist?(file)

  metas = PythonWorkflow.read_python_metadata(file)
  metas = [metas] unless Array === metas

  # For each function defined in the python file, register a workflow task
  metas.each do |meta|
    meta['returns'] = returns.to_s if returns
    task_desc = desc || meta['description']

    ruby_returns = PythonWorkflow.map_returns(meta['returns'])
    ruby_inputs  = meta['params'].map { |p| PythonWorkflow.map_param(p) }

    ruby_inputs.each do |inp|
      input(inp[:name].to_sym, inp[:type], inp[:desc], inp[:default], inp[:options] || {})
    end

    self.desc(task_desc) if task_desc && !task_desc.empty?
    self.extension(extension) if extension

    task({ meta['name'].to_sym => ruby_returns }) do |*args|
      arg_names = ruby_inputs.map { |i| i[:name] }
      values = {}
      arg_names.each_with_index { |n,i| values[n] = args[i] }

      argv = PythonWorkflow.build_python_argv(meta['params'], values)
      # prefix with function name so the python script runs the desired function
      full_argv = [meta['name']] + argv

      out = ScoutPython.run_file file, Shellwords.shelljoin(full_argv)
      # out is expected to respond to exit_status and read
      raise "Python task #{meta['name']} failed" unless out.exit_status == 0
      txt = out.read.to_s
      # try JSON
      begin
        next JSON.parse(txt)
      rescue JSON::ParserError
        # not JSON; for list returns, split by newline
        if ruby_returns == :array || ruby_returns == :file_array
          next txt.split("\n").map(&:to_s)
        end
        next txt.strip
      end
    end
  end
end