Load Rougail configuration from Rougail command line informations
==================================================================

There is a lot you can do with the Rougail command line (rougail-cli), but sometimes you need to do a more advanced script.

Rather than duplicating the configuration, why not load the information from the configuration file, environment variables, or command line options?

We can loading a combination of source information but always in this order:

- configuration file
- environment variables
- commandline options

.. warning:: specific options reserve for command line (in namespace "cli") are not available in script

Then let's create an structual file:term:`structure file` :file:`dist/00-base.yml`:

.. code-block:: yaml
   :caption: the :file:`dist/00-base.yml` file content

    \%YAML 1.2
    ---
    version: 1.1

    my_variable: my_value_extra  # a simple variable
    ...

Command line configuration file
-------------------------------

Create a command line configuration file :file:`.rougailcli.yml`:

.. code-block:: yaml
   :caption: the :file:`.rougailcli.yml` file content

    ---
    main_structural_directories:  # directories where are place structural file
      - dist
    step.output: json  # output is not console but json

Let's execute Rougail command line:

.. code-block:: bash

    $ rougail
    {
      "my_variable": "my_value_extra"
    }

Then, let's create the :term:`Tiramisu` objects via the following :file:`script.py` script:

.. code-block:: python
    :caption: the :file:`script.py` file content

    from rougail import Rougail
    rougail = Rougail()
    try:
        config = rougail.run()       
        print(config.value.get()) 
    except Exception as err:
        print(f"ERROR: {err}")
        exit(1)

Let's execute `script.py`:

.. code-block:: bash

    $ python3 script.py
    
    ERROR: option "Directories where structural files are placed" is mandatory but has no value

As expected, the .rougailcli.yml file is not loaded because it is specific to the command line.

Let's modifying the script to do this:

.. code-block:: python
    :caption: the :file:`script.py` file content

    from rougail import Rougail, RougailConfig
    from rougail.cli.rougailconfig import load
    load(RougailConfig, yaml_file=".rougailcli.yml")
    rougail = Rougail()
    try:
        config = rougail.run()       
        print(config.value.get()) 
    except Exception as err:
        print(f"ERROR: {err}")
        exit(1)

Let's execute `script.py`:

.. code-block:: bash

    $ python3 script.py
    {<TiramisuOption path="rougail">: {<TiramisuOption path="rougail.my_variable">: 'my_value_extra'}}

Environment variables
---------------------

If we don't have .rougailcli.yml, it's possible to set option with environment variables, like this:

.. code-block:: bash

    $ env ROUGAILCLI_MAIN_STRUCTURAL_DIRECTORIES=dist/ ROUGAILCLI_STEP.OUTPUT=json ROUGAILCLI_MAIN_NAMESPACE=test bin/rougail
    {
      "test": {
        "my_variable": "my_value_extra"
      }
    }

Do the same with a script:

.. code-block:: python
    :caption: the :file:`script.py` file content

    from rougail import Rougail, RougailConfig
    from rougail.cli.rougailconfig import load
    load(RougailConfig, env_prefix="ROUGAILCLI")
    rougail = Rougail()
    try:
        config = rougail.run()       
        print(config.value.get()) 
    except Exception as err:
        print(f"ERROR: {err}")
        exit(1)

Let's execute `script.py`:

.. code-block:: bash

    $ env ROUGAILCLI_MAIN_STRUCTURAL_DIRECTORIES=dist/ ROUGAILCLI_STEP.OUTPUT=json ROUGAILCLI_MAIN_NAMESPACE=test python3 script.py 
    {<TiramisuOption path="test">: {<TiramisuOption path="test.my_variable">: 'my_value_extra'}}

Command line option
-------------------

To reproduce this:

.. code-block:: bash

   ./bin/rougail --main_structural_directories dist/ --step.output json --main_namespace=new_test
   {
     "new_test": {
       "my_variable": "my_value_extra"
     }
   }

Do this script:

.. code-block:: python
   :caption: the :file:`script.py` file content

   from rougail import Rougail, RougailConfig
   from rougail.cli.rougailconfig import load
   load(RougailConfig, commandline=True)
   rougail = Rougail()
   try:
       config = rougail.run()       
       print(config.value.get()) 
   except Exception as err:
       print(f"ERROR: {err}")
       exit(1)

.. code-block:: bash

   $ python3 script.py --main_structural_directories dist/ --step.output json --main_namespace=new_test
   {<TiramisuOption path="new_test">: {<TiramisuOption path="new_test.my_variable">: 'my_value_extra'}