redis-helper 0.3.1

Easily store, index, and modify Python dicts in Redis (with flexible searching)

On install, the sample settings.ini file will be copied to the ~/.config/redis-helper directory.

Install latest tag of redis-helper from pypi

% pip install redis-helper

Install latest commit on master of redis-helper from github

% pip install git+git://github.com/kenjyco/redis-helper

Local development setup

% git clone https://github.com/kenjyco/redis-helper
% cd redis-helper
% python3 setup.py test     # optional, requires 'setuptools'
% ./dev-setup.bash

The dev-setup.bash script will create a virtual environment in the ./venv directory with extra dependencies (ipython, pdbpp, pytest), then copy settings.ini to the ~/.config/redis-helper directory.

Running tests in development setup

% venv/bin/py.test tests

or

% venv/bin/py.test -vsx -rs --pdb tests

The py.test options will run tests in a verbose manner and output the reason why tests were skipped (if any were skipped). If there are any failing tests, py.test will stop on the first failure and drop you into the debugger.

Usage

>>> import redis_helper as rh
>>> collection = rh.Collection(..., index_fields='field1,field3')
>>> hash_id = collection.add(field1='', field2='', field3='', ...)
>>> collection.add(...)
>>> collection.add(...)
>>> collection.update(hash_id, field1='', field4='', ...)
>>> change_history = collection.old_data_for_hash_id(hash_id)
>>> data = collection.get(hash_id)
>>> some_data = collection.get(hash_id, 'field1,field3')
>>> results = collection.find(...)
>>> results2 = collection.find('field1:val,field3:val', ...)
>>> results3 = collection.find(..., get_fields='field2,field4')
>>> counts = collection.find(count=True, ...)
>>> top_indexed = collection.index_field_info()
>>> collection.delete(hash_id, ...)

Example

TODO

Settings, environments, testing, and debugging

When using venv/bin/py.test -vsx -rs --pdb tests, tests will stop running on the first failure and drop you into a pdb++ debugger session.

To trigger a debugger session at a specific place in the code, insert the following, one line above where you want to inspect

import pdb; pdb.set_trace()

To start the debugger inside test code, use

pytest.set_trace()

• use (l)ist to list context lines

• use (n)ext to move on to the next statement

• use (s)tep to step into a function

• use (c)ontinue to continue to next break point (i.e. set_trace() lines in your code)

• use sticky to toggle sticky mode (to constantly show the currently executing code as you move through with the debugger)

• use pp to pretty print a variable or statement

If the redis server at redis_url (in the test section of ~/.config/redis-server/settings.ini) is not running or is not empty, redis server tests will be skipped.

Use the APP_ENV environment variable to specify which section of the settings.ini file your settings will be loaded from. Any settings in the default section can be overwritten if explicity set in another section.

• if no APP_ENV is explicitly set, dev is assumed

• the APP_ENV setting is overwritten to be test no matter what was set when calling py.test tests

Background

A Python dictionary is a very useful container for grouping facts about some particular entity. Dictionaries have keys that map to values (so if we want to retrieve a particular value stored in a dictionary, we can access it through its key). The dictionary itself is accessed by its variable name.

Redis is a data structure server (among other things). It is great for storing various types of objects that can be accessed between different programs and processes. When your program stops running, objects that you have stored in Redis will remain. To retreive an object from Redis, you must access it through its key name (kind of like a Python variable name). The redis Python package provides the StrictRedis class, which contains methods that correspond to all of the Redis server commands.

A Redis hash is most similar to a Python dictionary. A “key” in a Python dictionary is analogous to a “field” in a Redis hash (since “key” means something different in Redis).