Casters

Program caster.py for command line management of couchdb design documents

Extracted out of scripts from social farm project at https://github.com/SocialFarm

Installation

Download the script and resources somewhere in your filesystem. Make the script available in your executable path.

For example do the following in /usr/local/bin:

ln -s /some/path/caster.py

Usage

Create a design document skeleton structure

caster.py [-d dirname] generate  

Push/pull a given design document's code to/from a couchdb

caster.py [-d dirname] pull couchdburl 

caster.py [-d dirname] push couchdburl 

For example:

caster.py -d ./testdesign pull http://usr:pwd@localhost:5984/testdb/_design/testdesign

Test cases

Creates view directory along with i) a running example test case, ii) a running sample library file which works through the common js modules (http://wiki.apache.org/couchdb/CommonJS_Modules), and iii) and a test harness to enforce identical execution of the map and reduce functions whether they execute on couchdb or on local system with user inspection/control.

You can safely delete the example/sample files (eg: in lib or tests directory)

Also note that -f will overwrite existing view on local directory.

caster.py [-d dirname] [-f] create view name

Run either a single view test cases or all the test cases in all the views

caster.py [-d dirname] test view name

caster.py [-d dirname] test

In general you can always go to the tests directory below the view directory and manually run the tests explicitly eg: js testExample.js

This feature can be used to for example profile your map or reduce function, eg using the xpc shell javascript interpreter: https://developer.mozilla.org/en-US/docs/Mozilla/XPConnect/xpcshell/Profiling

Similarly, one can interactively debug the execution of map/reduce functions with the visual rhino debugger: https://developer.mozilla.org/en-US/docs/Rhino/Debugger

Dependencies

couchdb-python : https://pypi.python.org/pypi/CouchDB python : tested with 2.7 , but should work a for a few older versions too.

To be implemented

caster.py [-d dirname] test [show|list|update|filters] name

caster.py [-d dirname] create [show|list|update|filters] name

caster.py [-d dirname] delete [view|show|list|update|filters] name

Directory stucture

designname/   (could be any dir though - design doc name seems safer)  

    _attachments/   (can have directory tree within here)

    views/
        lib/
        viewname1/
            map.js
            reduce.js
    shows
        show.js

    lists/ 
        listxxx.js

    updates/
        funcname.js

    filters/
        funcname.js 

    validate_doc_update.js

Goals for maintaining code in couchdb (views/lists/etc)

• identical code on couchdb and local fs (eg: no include code through comment as in couchapp)
• support common code includes consistent with couchdb through the "requires" construct
• this "identical code" can be run through tools like unit testing framework, debugger, and profiler - and can be better tracked through version control tools.

Additionally, the standard goals (supported by other tools)

• push your code to couchdb (TODO : skip push if identical)
• pull code from couchdb
• maintain any attachments - the attachment files should ideally be openable through browser on local system and relative links should also work

Relevant external information

Tuning javascript code

Javascript code used in map and reduce functions of couchdb is hard to properly tune while loaded in couchdb

One way to improve code performance is to run the code locally and time through js, eg:

js -b test.js

Readings and relevant links

http://wiki.apache.org/couchdb/JavascriptPatternViewCommonJs

http://wiki.apache.org/couchdb/CommonJS_Modules

https://developer.mozilla.org/en-US/docs/Mozilla/Projects/SpiderMonkey?redirectlocale=en-US&redirectslug=SpiderMonkey

https://github.com/WebReflection/wru