Trait Configurable 

pub trait Configurable:
    Serialize
    + DeserializeOwned
    + Default
    + Sized {
    // Provided methods
    fn load_layered_options(
        config_file: Option<&str>,
        env_prefix: &str,
    ) -> Result<Self> { ... }
    fn validate_sanitize(&mut self) -> Result<()> { ... }
    fn env_list_keys() -> Option<&'static [&'static str]> { ... }
    fn env_tagged_seq_keys() -> Option<&'static [&'static str]> { ... }
    fn to_toml(&self) -> Result<String> { ... }
}

Configuration trait defines the common interface for configuration that can be loaded from multiple sources and serialized to TOML.

Provided Methods

fn load_layered_options( config_file: Option<&str>, env_prefix: &str, ) -> Result<Self>

Load the configuration from multiple sources and merge them. The precedence order is: config file > environment variables > default values. env_prefix is the prefix of environment variables, e.g. “FRONTEND__xxx”. The function will use dunder(double underscore) __ as the separator for environment variables, for example: DATANODE__STORAGE__MANIFEST__CHECKPOINT_MARGIN will be mapped to DatanodeOptions.storage.manifest.checkpoint_margin field in the configuration. list_keys is the list of keys that should be parsed as a list, for example, you can pass Some(&["meta_client_options.metasrv_addrs"] to parse GREPTIMEDB_METASRV__META_CLIENT_OPTIONS__METASRV_ADDRS as a list. The function will use comma , as the separator for list values, for example: 127.0.0.1:3001,127.0.0.1:3002,127.0.0.1:3003.

fn validate_sanitize(&mut self) -> Result<()>

Validate(and possibly sanitize) the configuration.

fn env_list_keys() -> Option<&'static [&'static str]>

List of toml keys that should be parsed as a list.

fn env_tagged_seq_keys() -> Option<&'static [&'static str]>

Keys whose value is a sequence of single-key tagged tables (e.g. region_engine, serialized from Vec<Enum> with externally tagged variants). Environment variables address them by tag name (KEY__<TAG>__<FIELD>) instead of numeric index, and the overrides are merged onto the corresponding default entries.

Keys must name a top-level field of the options struct: the default entries to merge onto are looked up by literal key in the serialized defaults, so a dotted key is rejected instead of silently leaving the defaults out of the merged sequence.

A configuration file that configures such a key as a whole replaces the merged value, so the environment variables for it are ineffective then and the file has to spell out every entry it wants.

fn to_toml(&self) -> Result<String>

Serialize the configuration to a TOML string.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors