PyConfita: Confita-like for Python

Library that ease reading a value from multiple key-value stores/backends with ordered evaluation.

Disclaimer

Free implementation of the GO library Confita.

Features

• Backends/stores supported:
  • Environment variables (EnvBackend);
  • File (YAML format) (FileBackend);
  • Python dictionary object (DictBackend);
  • Vault key-value store (VaultBackend);
  • String parsing (serialized JSON) (StringBackend);
• Backends evaluation order: directly set by the order of backends in Confita.backends list. The last not None evaluated value is returned;
• Explicit type conversion supported for str, bool, int, float;
• Case sensitivity option: option to read key with casing variations (uppercased, lowercased).

Quickstart

from pyconfita import (
    LoggingInterface,
    Confita,
    EnvBackend,
    StringBackend,
    DictBackend,
    VaultBackend,
    FileBackend
)
dumb_logger = LoggingInterface()
c = Confita(
    logger=dumb_logger,
    backends=[
        FileBackend("/abs/path/vars.yaml"),
        DictBackend({"FOO": "bar"}),
        StringBackend("{'HELLO': 'WORLD'}"),
        VaultBackend(dumb_logger, default_key_path=f"path1"),
        EnvBackend(),
    ],
)

v = c.get("FOO") 
# At least DictBackend should evaluate it as not None
assert v is not None
# Type should be `str` 
assert isinstance(v, str)

Evaluation order

Evaluation is performed in order of the list of backends. Next backend has priority over previous backend to set the value.

import os
from pyconfita import (
    LoggingInterface,
    Confita,
    EnvBackend,
    DictBackend
)
dumb_logger = LoggingInterface()

os.environ.setdefault("KEY", "VALUE_FROM_ENV")

c = Confita(
    logger=dumb_logger,
    backends=[
        DictBackend({
            "KEY": "VALUE",
            "BOOL_1": "false",
            "BOOL_2": "true"
        }),
        EnvBackend(),
    ],
)

assert c.get("KEY") == "VALUE_FROM_ENV" # Environment backend overrides previous backends' values
assert c.get("BOOL_1") == "false" # No implicit type conversion 
assert c.get("BOOL_2", type=bool) # Explicit type conversion requested

# Reverse evaluation order by reversing list of backends
c = Confita(
    logger=dumb_logger,
    backends=[
        EnvBackend(),
        DictBackend({"KEY": "VALUE"}),
    ],
)

assert c.get("KEY") == "VALUE" # Dict backend overrides previous backends' values

Explicit type conversion

Type conversion must be explicit. Only str, bool, int, float types are supported. Default type is str.

from pyconfita import (
    LoggingInterface,
    Confita,
    DictBackend
)
dumb_logger = LoggingInterface()

c = Confita(
    logger=dumb_logger,
    backends=[
        DictBackend({
            "BOOL_1": "false",
            "BOOL_2": "true"
        }),
    ],
)

assert c.get("BOOL_1") == "false" # No implicit type conversion 
assert c.get("BOOL_2", type=bool) # Explicit type conversion requested

Case sensitivity

from pyconfita import (
    LoggingInterface,
    Confita,
    DictBackend
)
dumb_logger = LoggingInterface()

# Case sensitivity is enabled by default
c = Confita(
    logger=dumb_logger,
    backends=[DictBackend({"KEY": "VALUE"})],
)

assert c.get("KEY") == "VALUE" 
assert c.get("key") == None 

# Disable case sensitivity
c = Confita(
    logger=dumb_logger,
    backends=[DictBackend({"KEY": "VALUE"})],
    case_sensitive=False
)

assert c.get("KEY") == "VALUE" 
assert c.get("key") == "VALUE"