**********************
New Tethys App Project
**********************

**Last Updated:** June 2022

In this tutorial you will create a new Tethys App project using the scaffold. The following topics will be reviewed in this tutorial:

* Scaffolding New Tethys Apps
* Managing App Dependencies
* Adding a Custom Icon
* Customizing App Theme Color

.. figure:: ./resources/new_app_project_solution.png
    :width: 800px
    :align: center

1. Generate Scaffold
====================

To generate a new Tethys App using the scaffold, open a terminal and execute the following commands:

.. code-block:: bash

    # Activate the tethys environment
    conda activate tethys

.. code-block:: bash

    # Create a working directory (if it doesn't exist already)
    mkdir ~/tethysdev
    cd ~/tethysdev

.. code-block:: bash

    # Scaffold a new Tethys app
    tethys scaffold thredds_tutorial

You will be prompted to enter metadata about the app such as, proper name, version, author, and description. All of these metadata are optional. You can accept the default values by pressing enter, repeatedly.

In a file browser change into your :file:`Home` directory and open the :file:`tethysdev` directory. If the scaffolding worked, you should see a directory called :file:`tethysapp-thredds_tutorial`. All of the source code for your app is located in this directory. For more information about the app project structure, see :doc:`../../supplementary/app_project`.

2. Add App Dependencies to :file:`install.yml`
==============================================

App dependencies should be managed using the :file:`install.yml` instead of the :file:`setup.py`. This app will require the ``netcdf4``, ``siphon``, and ``owslib`` packages to allow it to use THREDDS services. All three packages are available on ``conda-forge``, which is the preferred Conda channel for Tethys. Open :file:`tethysapp-thredds_tutorial/install.yml` and add these dependencies to the ``requirements.conda`` section of the file:

.. code-block:: yaml

    # This file should be committed to your app code.
    version: 1.0
    # This should match the app - package name in your setup.py
    name: thredds_tutorial

    requirements:
      # Putting in a skip true param will skip the entire section. Ignoring the option will assume it be set to False
      skip: false
      conda:
        channels:
          - conda-forge
        packages:
          - netcdf4
          - siphon
          - owslib
      pip:

    post:


3. Development Installation
===========================

Install the app and it's dependencies into your development Tethys Portal. In a terminal, change into the :file:`tethysapp-thredds_tutorial` directory and execute the :command:`tethys install -d` command.

.. code-block:: bash

    cd ~/tethysdev/tethysapp-thredds_tutorial
    tethys install -d

4. Customize App Icon and Theme Color
=====================================

Download this :download:`Unidata App Icon <./resources/unidata_logo.png>` or find one that you like and save it to the :file:`public/images` directory. Modify the ``icon`` property of your :term:`app class` to reference the new image. Also change the ``color`` property to the ``#008e8d`` color:

.. code-block:: python

    class ThreddsTutorial(TethysAppBase):
        """
        Tethys app class for Thredds Tutorial.
        """

        name = 'THREDDS Tutorial'
        index = 'thredds_tutorial:home'
        icon = 'thredds_tutorial/images/unidata_logo.png'
        package = 'thredds_tutorial'
        root_url = 'thredds-tutorial'
        color = '#008e8d'
        ...

5. View Your New App
====================

1. Start up the development server to view the new app:

.. code-block:: bash

    tethys manage start

.. tip::

    To stop the development server press :kbd:`CTRL-C`.

    If you get errors related to Tethys not being able to connect to the database, start the database by running:

    .. code-block:: bash

        tethys db start

    You can also stop the Tethys database by running:

    .. code-block:: bash

        tethys db stop

2. Browse to `<http://127.0.0.1:8000/apps>`_ in a web browser and login. The default portal user is:

* **username**: admin
* **password**: pass

Verify the following:

1. The default app icon should be replaced with the custom image you added in step 4.
2. The primary color for the app should be a dark turquoise (see screenshot at the beginning of the tutorial).

6. Solution
===========

This concludes the New App Project portion of the THREDDS Tutorial. You can view the solution on GitHub at `<https://github.com/tethysplatform/tethysapp-thredds_tutorial/tree/new-app-project-solution-3.0>`_ or clone it as follows:

.. parsed-literal::

    git clone https://github.com/tethysplatform/tethysapp-thredds_tutorial.git
    cd tethysapp-thredds_tutorial
    git checkout -b new-app-project-solution new-app-project-solution-|version|