safitty 0.9.3

Safitty. Wrapper on JSON/YAML configs for Python.

Safitty

Safitty is a wrapper on JSON/YAML configs for Python. Designed with a focus on the safe get/set operations for deep-nested dictionaries and lists.

Installation

pip install -U safitty

Features

• Safe get for dictionaries and lists
• Safe set for dictionaries and lists
• Multiple keys at one get/set call.
• Several strategies, includes: Get the most deep non-null value by your keys, Get the last non-null container and more
• Value transformations to classes

Quickstart

import safitty

# Loads config YAML or JSON
config = safitty.load_config("/path/to/config.yml")

# Getting value from the config
safitty.get(config, "very", "deep", "call", default="This is the default value")

# Setting value into
safitty.set(config, "clients", 0, "address", value="localhost:8888")

Why do I need Safitty?

When you work with big and deep configs or API it's getting difficult to safely take and proccess values.

Imagine you have a YAML-file looks like code below and you want to read the first function's name

transforms:  
 - name: Normalize  
   function: ToTensor  
   params: null  

 - name: Padding  
   function: Pad  
   params:
      fill: 3  
      padding_mode: reflect

It is really complicated to check all for None like

import yaml
with open(config_path) as stream:
	config = yaml.load(stream)

result = config.get("transforms")
if result is not None:
	result = result[0]
	if result is not None:
		result = result.get("function")

if result is None:
	result = "identity"

Note that Python has no safe-method for lists, so if transforms were empty result = result[0] will raise an Exception. To avoid this, the code should be wrapped into try: ... except: ...

Safitty allows to do the same in more readable way

import safitty

# can load json or yaml
config = safitty.load_config(config_path)

# getter for any depth
result = safitty.get(config, "transforms", 0, "function", default="identity")

For reverse action there is set, method for setting value for any depth

# this expand inner list to fit length of 2 and set {'name': 'BatchNorm2d'}
safitty.set(config, "transforms", 2, "name", value="BatchNorm2d")

There are type aliases for get and set: safe_get and safe_set