kurde 0.2.0

Configuration Language

kurde

Simple configuration language based on Python.

Features

• Python syntax
• Flexible Enums
• Easily created nested dictionaries
• Direct addess to environment variables
• Calling/capturing shell commands
• Path manipulation
• Module re immediately available

Concepts

Kurde is pure Python with some built-ins added for your convenience (see below).

After invoking your script, any JSON-serializable variable defined in the global scope will be serialized and printed to stdout.

Alternatively you can define ROOT variable in the global scope. It will be considered as the root object to be serialized.

After installing Kurde, command kurde becomes available. Use it as:

kurde path/to/your/script.py

For clarity it is recommended to add kurde in the shebang of your script: #!/usr/bin/env kurde.

For more information see examples below.

Built-Ins

Variable	Value
Path	pathlib.Path
Dict	addict.Dict
Enum	simplenum.Enum
enum	simplenum
env	addict.Dict(**os.environ)
cmd	plumbum.local.cmd
re	re

For reference see:

• addict
• simple-enum
• plumbum

Examples

Simple Example

#!/usr/bin/env kurde

user = dict(
    name = 'admin',
    password = 'admin123',
)
remotes = [
    '192.168.0.100',
    '192.168.0.101',
    '192.168.0.102',
]
timeout = 100

Renders as:

{
  "user": {
    "name": "admin",
    "password": "admin123"
  },
  "remotes": [
    "192.168.0.100",
    "192.168.0.101",
    "192.168.0.102"
  ],
  "timeout": 100
}

Advanced Example

#!/usr/bin/env kurde

# Enum from `simple-enum` package is available.
# By default enum items are serialized by names.
class Color(Enum):
    red
    green
    blue
    white
    black

# Alternatively, enum items can be replaced by numbers assigned automatically.
class Priority(Enum, values=enum.from_zero):
    low
    medium
    high

# In the simple cases, standard dictionary is sufficient.
# It is serialized as JSON object.
theme = dict(
    foreground = Color.black,
    background = Color.green,
)

# Dictionary can be also created by assigning the the attributes.
# Dict comes from `addicts` package.
user = Dict()

# Environment variables can be accessed directly.
user.name = env.USER or 'admin'
user.full_name = "Tom Brown"

# Module re immediately available.
user.last_name = re.findall('[^ ]+', user.full_name)[-1]

# lists, dicts, sets are serialized as JSON arrays.
user.aliases = ('tommy', 'tbrown', 'brown')
user.nick = None

network = Dict()

# Non-existing attributes are created on the fly.
network.local.priority = Priority.medium

# Shell commands can be easily invoked.
# Behind `cmd` we get `plumbum.local.cmd`.
network.local.name = cmd.hostname().strip()

# pathlib.Path immediately available.
network.local.cert_path = Path(__file__).parent.absolute() / 'cert.pem'

# Closures and other constructs available.
network.remotes = {f"proxy{n}": f'192.168.0.{100 + n}' for n in range(3)}
network.remotes['localhost'] = '127.0.0.1'

Renders as:

{
  "theme": {
    "foreground": "black",
    "background": "green"
  },
  "user": {
    "name": "kendo",
    "full_name": "Tom Brown",
    "last_name": "Brown",
    "aliases": [
      "tommy",
      "tbrown",
      "brown"
    ],
    "nick": null
  },
  "network": {
    "local": {
      "priority": 1,
      "name": "precision",
      "cert_path": "/home/kendo/wrk/kurde/examples/cert.pem"
    },
    "remotes": {
      "proxy0": "192.168.0.100",
      "proxy1": "192.168.0.101",
      "proxy2": "192.168.0.102",
      "localhost": "127.0.0.1"
    }
  }
}

Example with ROOT defined

#!/usr/bin/env kurde

min_value = 2
max_value = 6

ROOT = Dict()
ROOT.numbers = list(range(min_value, max_value+1))

Renders as:

{
  "numbers": [
    2,
    3,
    4,
    5,
    6
  ]
}

Disclaimer

Kurde doesn't do any sandboxing. Invoke the scripts only if you absolutely trust them. You are doing it on your own responsibility.

Known Issues

There is an issue between addict and simplenum when calling Dict with enum items as arguments, e.g.:

theme = Dict(
    foreground = Color.white,
    background = Color.green,
)