Module loader 

YAML loading and shell-style ${ENV_VAR:-default} interpolation.

Two loading modes: load_yaml_with_env interpolates the raw file text before parsing (used for system.yaml, which is never served back to clients), while load_yaml preserves placeholders verbatim (used for gateway.yaml, whose contents the Admin API serves to the Web UI — resolved secrets must never appear there). Placeholders in gateway config are resolved at the point of consumption instead: plugin node config at graph-compile time via interpolate_env_json, route match rules and consumer credentials when the route table / consumer store are built.

Functions

coerce_scalar 🔒

Types a resolved full-placeholder value the way YAML types the same unquoted scalar: booleans and finite numbers; everything else None.

interpolate_env

Replaces ${VAR} and ${VAR:-default} patterns with environment variable values.

interpolate_env_json

Recursively interpolates ${ENV_VAR:-default} patterns in every string leaf of a JSON value — object values, array elements, and nested combinations — leaving numbers, booleans, and null untouched.

interpolated_replacement 🔒

The replacement for a string leaf containing ${...}, None for everything else (the ${ fast-path guard included).

load_yaml

Loads a YAML file and deserializes into T without resolving ${ENV_VAR} placeholders — they are preserved verbatim in the parsed structure.

load_yaml_with_env

Loads a YAML file, interpolates environment variables, and deserializes into T.