.. _devel:

*****************
Developer's Guide
*****************

.. note::

   We acknowledge that users and developers are two different groups of people, so the documents
   should eventually be separated. However, since these are still very early days of the project,
   this section is kept in the Stork ARM for convenience only.

Generating Documentation
========================

To generate documentation, simply type ``rake doc``. You need to have `Sphinx <http://www.sphinx-doc.org>`_
and `rtd-theme <https://github.com/readthedocs/sphinx_rtd_theme>`_ installed. The generated
documentation will be available in the ``doc/singlehtml`` directory.

Agent API
=========

The connection between the server and the agents is established using gRPC over http/2. The agent API
definition is kept in the ``backend/api/agent.proto`` file. For debugging purposes, it is possible
to connect to the agent using `grpcurl <https://github.com/fullstorydev/grpcurl>`_ tool. For example,
you can retrieve a list of currently provided gRPC calls by using this command:

.. code:: console

    $ grpcurl -plaintext -proto backend/api/agent.proto localhost:8888 describe
    agentapi.Agent is a service:
    service Agent {
      rpc detectServices ( .agentapi.DetectServicesReq ) returns ( .agentapi.DetectServicesRsp );
      rpc getState ( .agentapi.GetStateReq ) returns ( .agentapi.GetStateRsp );
      rpc restartKea ( .agentapi.RestartKeaReq ) returns ( .agentapi.RestartKeaRsp );
    }

You can also make specific gRPC calls. For example, to get the machine state, the following command
can be used:

.. code:: console

    $ grpcurl -plaintext -proto backend/api/agent.proto localhost:8888 agentapi.Agent.getState
    {
      "agentVersion": "0.1.0",
      "hostname": "copernicus",
      "cpus": "8",
      "cpusLoad": "1.68 1.46 1.28",
      "memory": "16",
      "usedMemory": "59",
      "uptime": "2",
      "os": "darwin",
      "platform": "darwin",
      "platformFamily": "Standalone Workstation",
      "platformVersion": "10.14.6",
      "kernelVersion": "18.7.0",
      "kernelArch": "x86_64",
      "hostID": "c41337a1-0ec3-3896-a954-a1f85e849d53"
    }

Installing git hooks
====================

There's a simple git hook that inserts the issue number in the commit message automatically. If you
want to use it, go to ``utils`` directory and run ``git-hooks-install`` script. It will copy the
necessary file to ``.git/hooks`` directory.


ReST API
========

The primary user of ReST API is Stork UI in web browser. The definition of ReST API is located
in api folder and is described in Swagger 2.0 format.

The description in Swagger is split into multiple files. 2 files comprise a tag group:

* \*-paths.yaml - defines URLs
* \*-defs.yaml - contains entity definitions

All these files are combined by ``yamlinc`` tool into signle swagger file ``swagger.yaml``.
Then from ``swagger.yaml`` there are generated code for:

* UI fronted by swagger-codegen
* backend in Go lang by go-swagger

All these steps are realized in Rakefile.