attributes.md

attributes: element

Optional

Contains definition of data that passed into executable scripts as a single parameter.

This is the single source of true for PWSHAKE engine about all inputs used by the pwshake.yaml config processing.

This parameter should be of type Powershell [hashtable] that allows to merge, interpolate and override contained values during PWSHAKE execution.

• attributes: example

  attributes:
    some_attribute: 
      nested_attribute1: this is 1
      nested_attribute2: that is 2
    composed_attribute:
    - 1
    - 2
    - 3
  

  The given example is transformed in the following Powershell [hashtable] and passed by PWSHAKE engine to every executable script defined in the tasks: element.

  @{
    attributes=@{
      some_attribute=@{
        nested_attribute1="this is 1";
        nested_attribute2="that is 2";
      };
      composed_attribute=@(1,2,3);
    }
  }
  

• attributes: merging

  The pwshake.ps1 bootstrapper script can accept additional -MetaData parameter that merges given parameter value into the attributes element:

  PS>./pwshake.ps1 -MetaData "env_name=shake42"
  

  Output (the pwshake_path value is merged by PWSHAKE engine):

  PWSHAKE config:
  attributes:
    env_name: "shake42"
    pwshake_path: /absolute/path/to/your/working/directory/MyRepo
  ...
  

  See more about the -MetaData parameter of bootstrapper pwshake.ps1 script

• attributes: interpolation

  Values of several attributes can be reused and/or composed by simple interpolation syntax: {{key-to-be-interpolated}}

  PS> cat ./pwshake.yaml
  attributes:
    win_fqdn: "{{env_name}}-windows.{{override_to}}"
  ...
  

  PS>./pwshake.ps1 -Metadata @{env_name="shake42";override_to="test"}
  PWSHAKE config:
  attributes:
    env_name: shake42
    override_to: test
    pwshake_path: /absolute/path/to/your/working/directory/MyRepo
    win_fqdn: shake42-windows.test
  ...
  

  If attributes: has deep hierarchical structure it can be interpolated with dot syntax {{key.to.be.interpolated}}

  PS> cat ./pwshake.yaml
  attributes:
    a:
      b:
        c: d
    e: "{{a.b.c}}"
  ...
  

  PS>Invoke-pwshake
  PWSHAKE config:
  attributes:
    a:
      b:
        c: d
    e: d
  ...
  

  If keys given by interpolation syntax are not present either in attributes: element or in -MetaData parameter value they are evaluated with empty string

  PS> cat ./pwshake.yaml
  attributes:
    win_fqdn: "{{env_name}}-windows.shake.{{override_to}}"
  ...
  

  PS>./pwshake.ps1
  PWSHAKE config:
  attributes:
    pwshake_path: /absolute/path/to/your/working/directory/MyRepo
    win_fqdn: -windows.shake.
  ...
  

  Evaluation of environment variables

  PWSHAKE supports simple evaluation of environment variables in interpolation syntax similar to Powershell syntax {{$env:COMPUTERNAME}}

  PS>$env:SOME_VAL="fi1432"
  

  PS>./pwshake.ps1 -Metadata 'env_name={{$env:SOME_VAL}}-windows'
  PWSHAKE config:
  attributes:
    pwshake_path: /absolute/path/to/your/working/directory/MyRepo
    env_name: fi1432-windows
  ...
  

  Evaluation Powershell expressions

  If it's required to evaluate dynamic value of attribute, there is an ability to do this with general Powershell string interpolation syntax "$(...)".

  Examples:

  PS>./pwshake.ps1 -Metadata 'env_name={{$([System.Environment]::MachineName)}}'
  ...
  

  PS>./pwshake.ps1 -Metadata 'env_id={{$("env-$([System.Guid]::NewGuid())")}}'
  ...
  

• attributes: overriding

  See more about attributes_overrides: element