Config Util

oqtopus_util.config provides utility functions for loading YAML configuration files with environment-variable substitution, masking sensitive values, and applying logging configuration.

Functions

load_config

from oqtopus_util.config import load_config

config = load_config("config/config.yaml")

load_config(config_path) reads a YAML file and returns a Python dict.

Before the file is parsed by PyYAML, every ${VAR} and ${VAR, default} placeholder is replaced at the string level, allowing YAML to apply its own type-casting rules.

Placeholder	Environment variable set	Result
${VAR}	Yes	Raw value of VAR (string; YAML casts the surrounding context)
${VAR}	No	null (YAML None)
${VAR, default}	Yes	Raw value of VAR
${VAR, default}	No	default — YAML type-casts it (e.g. 10 → int, false → bool)

String values that start with ~ are expanded to absolute home-directory paths (equivalent to Path(value).expanduser()).

Example config.yaml

server:
  host: ${HOST, localhost}
  port: ${PORT, 8080}
  debug: ${DEBUG, false}
  data_dir: ~/oqtopus/data

import os
from oqtopus_util.config import load_config

os.environ["HOST"] = "example.com"

cfg = load_config("config/config.yaml")
# cfg["server"]["host"]     == "example.com"
# cfg["server"]["port"]     == 8080          (int, cast by YAML)
# cfg["server"]["debug"]    is False         (bool, cast by YAML)
# cfg["server"]["data_dir"] == "/home/user/oqtopus/data"

mask_sensitive_info

from oqtopus_util.config import mask_sensitive_info

safe_cfg = mask_sensitive_info(config)

mask_sensitive_info(config) returns a copy of the configuration dictionary where the values of the following keys are replaced with "***MASKED***":

• api_key
• api_token
• password
• secret_key

The function processes nested dictionaries recursively, so sensitive values at any depth are masked.

Example

from oqtopus_util.config import mask_sensitive_info

config = {
    "database": {
        "host": "localhost",
        "password": "s3cr3t",
    },
    "api_token": "abc123",
}

safe = mask_sensitive_info(config)
# safe["database"]["password"] == "***MASKED***"
# safe["api_token"]            == "***MASKED***"
# safe["database"]["host"]     == "localhost"

setup_logging

from oqtopus_util.config import setup_logging

setup_logging(logging_cfg)

setup_logging(logging_cfg) applies a logging configuration dictionary by calling logging.config.dictConfig.

The logging_cfg argument must be a Python dict. A TypeError is raised if a non-dict value is passed.

Example

from oqtopus_util.config import load_config, setup_logging

logging_cfg = load_config("config/logging.yaml")
setup_logging(logging_cfg)

Example logging.yaml

version: 1
formatters:
  default:
    format: "%(asctime)s %(levelname)s %(message)s"
handlers:
  console:
    class: logging.StreamHandler
    formatter: default
    stream: ext://sys.stdout
root:
  level: INFO
  handlers: [console]
disable_existing_loggers: false

Complete Example

import logging
from oqtopus_util.config import load_config, mask_sensitive_info, setup_logging

# Load main configuration
config = load_config("config/config.yaml")

# Set up logging first
logging_cfg = load_config("config/logging.yaml")
setup_logging(logging_cfg)

logger = logging.getLogger(__name__)

# Log configuration without exposing secrets
safe_cfg = mask_sensitive_info(config)
logger.info("Loaded configuration: %s", safe_cfg)