Hello World Example
===================

Graph Creation
--------------

This video provides detailed instructions for constructing the "Hello World" :doc:`Logical Graph Template <graphs>`. In most documentation, and the EAGLE interface, this is referred to as a graph. It is a visual depiction of the relationships between different :doc:`components <components>` integrated into a workflow. You can also directly play around with the editor and the HelloWorld example graph on our `public installation <https://eagle.icrar.org/?service=GitHub&repository=ICRAR/EAGLE-graph-repo&branch=master&path=examples&filename=HelloWorld-simple.graph>`_. The rest of this document provides a detailed description of the functionality and usage of EAGLE.


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    :file: _static/helloWorld_creation_video.html

The graph cannot itself be executed on any hardware; it must first be translated into a :doc:`Physical Graph Template <graphs>` via an algorithm that will optimise it for efficiency and parallel processing. This translated graph can then be entered into the queue on the chosen facility for execution.

Saving a graph to GitHub
------------------------

To save a graph to GitHub, you will need to add a repository that you have permission to write to. You may need to create a new repository if you don't already have access to one.

A GitHub Personal Access Token is required to save a graph to a repository. The steps required to generate one are demonstrated in the following video, as well as adding a custom repository. You can also follow the `instructions on GitHub <https://docs.github.com/en/enterprise-server@3.4/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token>`_.

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    :file: _static/helloWorld_save_graph.html

Translating a graph
-------------------

The graph created in EAGLE needs to be translated into a :doc:`Physical Graph Template <graphs>` before it can be executed. This video will step you through the process of translating a simple Hello World graph.

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    :file: _static/helloWorld_translate_graph.html

Executing a graph
-----------------

This video shows one method of executing the :doc:`Physical Graph Template <graphs>` using a an execution engine that is running in a local Docker container. There are many other ways this step may be performed.

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    :file: _static/helloWorld_execute_graph.html