Lesson 13 - System Properties

Goal

In this lesson we’ll learn how to use system properties to set the values of inputs.

Get Started

We’ll need to create a system property file that contains the values we want to use for the inputs. Let’s create a properties folder under tutorials and in there create a file named bcompany.yaml. We’ll also need to use the system properties somewhere. We’ll use then in the new_hire.sl generate_user_email.sl files.

System Properties File

The first thing to take note of is that our system properties file ends with a .yaml extension instead of the .sl one we’ve been using for our flows and operations. That’s because the system properties files are not compiled and there isn’t really anything special about them. They’re flat YAML files that contain maps of fully qualified names to their values.

Here’s what the contents of our system properties file looks like:

tutorials.hiring.domain: bcompany.com
tutorials.hiring.hostname: <host name>
tutorials.hiring.port: '<port>'
tutorials.hiring.system_address: <system email>
tutorials.hiring.hr_address: <hr email>

You’ll need to substitute the values in angle brackets (<>) to work for your email host.

Note: the port property must have quotes (') around the value so that it is correctly interpreted as a YAML string and not an integer value.

Inputs

Now we need to use the system properties to place values in our inputs. We’ll do this in two places.

First, we’ll add a system property to the inputs of generate_user_email by adding the system_property property to the domain input using the fully qualified name from the system properties file.

inputs:
  - first_name
  - middle_name:
      default: "''"
  - last_name
  - domain:
      system_property: tutorials.hiring.domain
      default: "'acompany.com'"
      overridable: false
  - attempt

Let’s see how the system property works in relation to other possible values for the input. To do so, we’ll just run the generate_user_email operation by itself and test what happens when we experiment with explicitly passing values or not and commenting/uncommenting the default and system property values.

Save the file and try a few of the variations starting with:

run --f <folder path>/tutorials/hiring/generate_user_email.sl --i first_name=john,last_name=doe,domain=company.com,attempt=1 --spf <folder path>/tutorials/properties/bcompany.yaml

In general, the order of preference as to which values get bound to the input variable is:

1. Explicitly passed value
2. System properties
3. Default value

However, if the overridable property is set to false, explicitly passed values will not be bound to the input variable. Instead, a system property or default value will be bound.

The second place we’ll add system properties is to the new_hire flow. Here we’ll add the necessary variables with system properties to the inputs section and use them in the send_mail task we created last lesson. We’ll have the hostname, port, from and to taken from the system properties file.

inputs:
  - first_name
  - middle_name:
      required: false
  - last_name
  - missing:
      default: "''"
      overridable: false
  - total_cost:
      default: 0
      overridable: false
  - order_map: >
      {'laptop': 1000, 'docking station':200, 'monitor': 500, 'phone': 100}
  - hostname:
      system_property: tutorials.hiring.hostname
  - port:
      system_property: tutorials.hiring.port
  - from:
      system_property: tutorials.hiring.system_address
  - to:
      system_property: tutorials.hiring.hr_address

- send_mail:
    do:
      mail.send_mail:
        - hostname
        - port
        - from
        - to
        - subject: "'New Hire: ' + first_name + ' ' + last_name"
        - body: >
            'Created address: ' + address + ' for: ' + first_name + ' ' + last_name + '<br>' +
            'Missing items: ' + missing + ' Cost of ordered items: ' + str(total_cost)
    navigate:
      FAILURE: FAILURE
      SUCCESS: SUCCESS

Run It

We can save the files and run the flow to see that the values are being taken from the system properties file we specify. If we want to swap out the values with another set, all we have to do is point to a different system properties file.

run --f <folder path>/tutorials/hiring/new_hire.sl --cp <folder path>/tutorials/base,<folder path>/tutorials/hiring,<content folder path>/base --i first_name=john,last_name=doe --spf <folder path>/tutorials/properties/bcompany.yaml

Up Next

In the next lesson we’ll see how to use 3rd Python packages in your operation’s actions.

New Code - Complete

new_hire.sl

namespace: tutorials.hiring

imports:
  base: tutorials.base
  mail: io.cloudslang.base.mail

flow:
  name: new_hire

  inputs:
    - first_name
    - middle_name:
        required: false
    - last_name
    - missing:
        default: "''"
        overridable: false
    - total_cost:
        default: 0
        overridable: false
    - order_map: >
        {'laptop': 1000, 'docking station':200, 'monitor': 500, 'phone': 100}
    - hostname:
        system_property: tutorials.hiring.hostname
    - port:
        system_property: tutorials.hiring.port
    - from:
        system_property: tutorials.hiring.system_address
    - to:
        system_property: tutorials.hiring.hr_address

  workflow:
    - print_start:
        do:
          base.print:
            - text: "'Starting new hire process'"

    - create_email_address:
        loop:
          for: attempt in range(1,5)
          do:
            create_user_email:
              - first_name
              - middle_name:
                  required: false
              - last_name
              - attempt
          publish:
            - address
          break:
            - CREATED
            - FAILURE
        navigate:
          CREATED: get_equipment
          UNAVAILABLE: print_fail
          FAILURE: print_fail

    - get_equipment:
        loop:
          for: item, price in order_map
          do:
            order:
              - item
              - price
          publish:
            - missing: self['missing'] + unavailable
            - total_cost: self['total_cost'] + cost
        navigate:
          AVAILABLE: print_finish
          UNAVAILABLE: print_finish

    - print_finish:
        do:
          base.print:
            - text: >
                'Created address: ' + address + ' for: ' + first_name + ' ' + last_name + '\n' +
                'Missing items: ' + missing + ' Cost of ordered items: ' + str(total_cost)

    - send_mail:
        do:
          mail.send_mail:
            - hostname
            - port
            - from
            - to
            - subject: "'New Hire: ' + first_name + ' ' + last_name"
            - body: >
                'Created address: ' + address + ' for: ' + first_name + ' ' + last_name + '<br>' +
                'Missing items: ' + missing + ' Cost of ordered items:' + str(total_cost)
        navigate:
          FAILURE: FAILURE
          SUCCESS: SUCCESS

    - on_failure:
      - print_fail:
          do:
            base.print:
              - text: "'Failed to create address for: ' + first_name + ' ' + last_name"

generate_user_email.sl

namespace: tutorials.hiring

operation:
  name: generate_user_email

  inputs:
    - first_name
    - middle_name:
        default: "''"
    - last_name
    - domain:
        system_property: tutorials.hiring.domain
        default: "'acompany.com'"
        overridable: false
    - attempt

  action:
    python_script: |
      attempt = int(attempt)
      if attempt == 1:
        address = first_name[0:1] + '.' + last_name + '@' + domain
      elif attempt == 2:
        address = first_name + '.' + first_name[0:1] + '@' + domain
      elif attempt == 3 and middle_name != '':
        address = first_name + '.' + middle_name[0:1] + '.' + last_name + '@' + domain
      else:
        address = ''
      #print address

  outputs:
    - email_address: address

  results:
    - FAILURE: address == ''
    - SUCCESS

bcompany.yaml

tutorials.hiring.domain: bcompany.com
tutorials.hiring.hostname: <host name>
tutorials.hiring.port: '<port>'
tutorials.hiring.system_address: <system email>
tutorials.hiring.hr_address: <hr email>

Note: You need to substitute the values in angle brackets (<>) to work for your email host.