Configuration

siderite::config (crate siderite-config) loads Settings with figment.

Sources and precedence

Lowest to highest:

1. compiled defaults
2. TOML files (file for a required file, file_optional for an optional one)
3. the environment
4. programmatic overrides (set)

Overrides always win, whatever order the builder calls come in. Files and environment sources merge in the order they are added.

use siderite::config::{ConfigBuilder, load};

// siderite.toml (optional) + SIDERITE_* + DATABASE_URL / ADDR
let settings = load()?;

let settings = ConfigBuilder::new()
    .file("config/app.toml")
    .env_prefix("MYAPP_")
    .set("app.debug", true)
    .build()?;

Environment keys use __ for nesting once the prefix is stripped: SIDERITE_DATABASES__ANALYTICS__URL sets databases.analytics.url. env_prefix also maps two unprefixed aliases, and prefixed keys win over them:

Variable	Key
DATABASE_URL	databases.default.url
ADDR	server.addr

extract::<T>() deserializes the same merged tree into your own type, so application-specific sections can live next to the built-in ones.

Settings

secret_key = "change-me"

[app]
name = "blog"          # default "siderite"
debug = false

[server]
addr = "0.0.0.0:8080"  # default "127.0.0.1:8000"

[databases.default]
url = "postgres://app:pw@db/app"
max_connections = 10

[databases.analytics]
url = "sqlite://analytics.db"

[cache]
url = "redis://cache:6379/0"
max_entries = 1024

[log]
level = "info"
json = false

Secrets

Database URLs, cache.url, and secret_key are Secret<String>.

• Debug and Display print [REDACTED]. Call expose() to read the value.
• There is no Serialize impl, so a secret cannot be written back out by accident.
• ConfigError messages never include the value of a secret-looking key (url, password, token, secret_key, api_key, …).

Tracing and the CLI

• init_tracing(&settings.log) installs a subscriber. RUST_LOG overrides log.level, and log.json selects JSON output. See Observability.
• CliSettings::from(&settings) hands the address and database URLs to AppCli. See CLI.

See also

• CLI
• Cache
• Database routing