Development guidelines

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Development Guidelines

Coding style

Java

Use the coding style imported from here: google-styleguide. You may experience issues with importing to the latest version of Eclipse. You may need to manually set the indentation length to four spaces. This file works perfectly in IntelliJ Idea with [this plugin] (https://plugins.jetbrains.com/plugin/6546?pr=idea) installed.

Python

Follow the standard [PEP8] (https://www.python.org/dev/peps/pep-0008/) style. Pycharm (which is basically Idea IDE with a Python plugin) checks for PEP8 compliance by default. The only thing you should do differently that PEP8 recommends are docstrings. Format the docstrings using [reStructuredText] (https://www.python.org/dev/peps/pep-0287/) style as shown below:

class ExampleClass():
    
    """
    This docstring says about the role of this class.
    """

    def example_method(self, count):
        """
        This method creates a list of consecutive numbers of the given length.
        :param int count: Length of the requested list.
        :returns: A list of consecutive numbers, starting from 0.
        :rtype: list[int]
        :raises ValueError: When count is less than zero.
        """
        if count < 0:
            raise ValueError('count can't be lesser than zero')
        return [i for i in range(count)]

Note: remember to document every public method!

PyCharm generates stubs for those types of docstrings. Type """ or ''' after a function or a class declaration and press Enter or Space.

Unit testing

• Use one unit test per one tested state according to: (http://blog.8thlight.com/uncle-bob/2013/09/23/Test-first.html)
• Use the following naming convention: testedFunctionName_testedState_expectedResult or checkToken_tokenInvalid_returnFalse Read more about this concept on blog: (http://osherove.com/blog/2005/4/3/naming-standards-for-unit-tests.html)
• Use meaningful asserts rather than "assertThat(result, is(expected))" in order to write good assert messages.
• Do not use field injection, inject into the constructor instead so there will be no need to mock private fields etc.

License Maven Plugin and Pre-commit Git Hooks

License Maven Plugin is a command line tool which allow us to change both the style and content of license headers in our sources files.
If you are working on Java projects, there should be a pom.xml file in the root directory. In that case, you can simply use the tool from terminal:

• mvn license:check - checking do all of our sources files have a proper headers
• mvn license:remove - removing headers
• mvn license:format - adding headers

If you aren't working on Java projects (bash, go, scala...), there should be a license_checker.xml file in the license_checker directory. In this case use:

• mvn -f license_checker/license_checker.xml license:remove

You can add the functionality to check that your files have proper headers before committing. You can accomplish this by applying the following steps:

• open project_root_directory/.git/hooks
• find a pre-commit.sample file and rename it to pre-commit
• for Java projects, change the content to:

  #!/bin/sh
  cd license
  ./header_check.sh

• for other languages, change cd/license to cd/license_checker

Additional reading:

• FAQs
• [Microservices Architecture for Spring on Cloud Foundry] (https://docs.google.com/document/d/15G8ew0qEDqpuBTWH9YGHKhda6HaLvfKuS4pnB-CPm50/mobilebasic).
• Microservices and the principles of 12 factor app.
• [Richardson Maturity Model] (http://martinfowler.com/articles/richardsonMaturityModel.html).
• [CloudFoundry documentation] (https://docs.cloudfoundry.org/).
• [example CloudFoundry app - Spring Music] (https://github.com/cloudfoundry-samples/spring-music)
• Single Page App
• Oauth2, JWT token
• Hadoop, MapReduce
• Apache Spark