Compass Core Python Modules
===========================
`compass/` is where all the core python modules of compass are, including API, DB, tasks and installers and so on.

##Direcotries and Files

    * apiclient/ - API client.
        * example.py - example code to deploy a cluster by calling compass API client.
        * restful.py - compass API client library.
        * v1/ - deprecated directory.

    * api/ - API related files go here.
        * api.py - defines compass RESTful API.
        * api.raml - raml file to display/document compass RESTful api.
        * auth_handler.py - handles API authentication.
        * exception_handlers.py - handles API exceptions.
        * utils.py - utilities for API.
        * v1/ - deprecated directory.

    * db/ - compass database modules.
        * api/ - Database level API interfaces, which includes all compass primitive data types.
               - This is the wrapper layer of the ORM tables and expose the useful logic of DB accessing.
        * callback.py - metadata callback methods.
        * config_validation/ - configuration validation module.
        * exception.py - compass defined exceptions for database module.
        * models.py - database model file, defining all compass database tables.
        * validator.py - database validation methods.
        * vi/ - deprecated directory.


    * tasks/ - all celery tasks are defined here, and they asynchronously exercise functions in the ./actions directory.
        * client.py - module to setup celery client.
        * tasks.py - defines all celery tasks.

    * actions/ -  wrappers of heavy-lifting utility functions located in ./deployment,
    ./hdsdiscovery, ./log_analyzor
        * health_check/ that does a health
            check on compass and output diagnoses.

    * deployment/ - backend deployment module that handles upstream data and dumps to installers
            * deployment_manager.py - deployment dispatcher that defines interfaces and retrieves/updates configurations.
            * installers - contains base installers and its children installers such as os_installer and pk_installer
              (package_installer). These installers here are the "plugin" kind of files that interact with installer
              tools(e.g. chef) that do the real installation tricks.
            * utils/ - utility module that contains a constant.py which defines all keyword variables for deployment.

    * hdsdiscovery/ - hardware discovery module, mainly for mac-address retrieval from switches.
            * base.py - a base class that can be extended by vendors under vendor/ directory.
            * error.py - hdsdiscovery module error handling.
            * hdmanager.py - manages hdsdiscovery functionalities.
            * SNMP_CONFIG.md - instructions on how to install and configure snmp related modules/packages.
            * utils.py - contains utility functions for hdsdiscovery.
            * vendors/ - switch/hardware vendor specific plugins. To support a new vendor:
                    1. Make sure the switch product supports SNMP.
                    2. Make sure the switch product uses standard MIB.
                    3. Add a corresponding plugin under vendors/.
                using arista as an example, first a python file with the same name of its parent directory should be added
                (e.g: arista.py). Define the class_name in the vendor file as "Arista" and give the class identical name.
                Then create a subdirectory called "plugins" and place mac.py under it.

    * log_analyzor/ - compass progress tracking module.
            * adapter_matcher.py - module to provide installing progress calculation for the adapters.
            * file_matcher.py - updates installing progresses by processing the log files.
            * line_matcher.py - updates/gets progress when a matched line is found in log files.
            * progress_calculator.py: provides functions to update installing progresses.


    * utils/ - compass core module utility functions.

    * tests/ - all unittest code

    * test_serverside/ - tests for installers(now only supports chef).