153 lines
3.8 KiB
ReStructuredText
153 lines
3.8 KiB
ReStructuredText
==========================
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Refactoring for fuelclient
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==========================
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https://blueprints.launchpad.net/fuel/+spec/refactoring-for-fuelclient
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We need to perform refactoring for fuelclient for improving reusability for
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its code base and gain more control for both whole system and particular parts
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of it.
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Problem description
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===================
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Now there are several issues in architecture of the project which cause
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difficulties in maintaining, implementing new logic and reusing existing
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code. These parts are:
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* APIclient code for maintaining http communication with nailgun server;
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now slightly obsolete python module urllib2 is using so code for request
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operations is pretty excessive
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* Formatter for console output; own written invention so it is hard to dive
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into, also not flexible for future changes
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* Objects hierarchy; is overwhelming with many interconnections
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between objects, may be simplified
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* Tests coverage; now only limited set of tests that check simple use
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cases is present, so it must be extended and if possible whole testing
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system should be rewritten to meet OS best practices in cli testing.
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Proposed change
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===============
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There are several proposes for every problem mentioned in previous section:
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* substitute urllib2 with requests module, this will leads to more simplified
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code in APIclient
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* include cliff framework for cli and formatter part of the system
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* perform minor refactoring when it needed.
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Alternatives
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------------
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All other basic tools such argparse or docopt doesn't suffice in case of
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fuelclient because we need to implement our own object hierarchy instead of
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using base classes of framework which leads to complicated structure as that
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we have now. There also others framework for building cli application
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(e.g. http://click.pocoo.org/) but chosen tools are wide using in OS community
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and are best practices for building OS related application.
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Data model impact
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-----------------
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None
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REST API impact
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---------------
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None
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Upgrade impact
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--------------
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Refactoring requires some additional packages to be installed on master node
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so they should be present after upgrade to version which includes change
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upon the table.
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Security impact
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---------------
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None
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Notifications impact
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--------------------
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None
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Other end user impact
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---------------------
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End users workflow may be affected as interface of system
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will be changed so adequate documentation must be provided for them
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Performance Impact
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------------------
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None
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Other deployer impact
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---------------------
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One should add needed rpm's to fuelclient spec. Packages must be already
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present in repos.
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Developer impact
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----------------
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After refactoring particular parts of the system may be reused in other
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projects when such functionality is needed as ostf, system tests etc.
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Also using cliff simplifying addition of new cli actions trough
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mechanism of entry points for package.
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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aroma-x
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Work Items
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----------
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Whole task may be divide into following separate changes:
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* plugging requests
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* plugging cliff
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Dependencies
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============
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Refactoring relies on additional package - python-cliff
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Testing
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=======
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As purpose of the refactoring is to bring well recommended itself in OS
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community technologies and tools it is naturally that testing system must be
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changed too in order to use best practices from corresponding OS development
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area, i.e. testing of cli clients. Also current coverage of use cases must be
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extended as it is not enough for such big project as nailgun.
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Documentation Impact
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====================
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Interface of fuelclient may be changed after refactoring so it must be
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mirrored into corresponding documentation
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References
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==========
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Cliff documentation:
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http://cliff.readthedocs.org/en/latest/
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Requests documentation:
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http://docs.python-requests.org/en/latest/
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