Crate tanzim_load 

tanzim-load

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First stage of the tanzim pipeline: reads raw configuration bytes from a declared source.

The Load trait

Implement Load to add a new source kind (protocol, service, database, …). It only fetches bytes — parsing happens in a later stage. The contract:

• Return one Payload per config entry found; a single source may expand to many entries. Finding nothing is Ok(vec![]), not an error.
• Set Payload::source on each entry to the concrete resource loaded (narrow the incoming source with Source::with_resource) so diagnostics stay precise.
• Payload::maybe_name is the entry name (None merges into the root); Payload::maybe_format is a parser hint (e.g. json).
• Read options off the source with Source::options() and the typed OptionValue accessors. Only validate options your loader reads; ignore unknown keys. Pick the Error variant that matches the failure (InvalidResource, InvalidOption, NotFound, NoAccess, Timeout, Duplicate, Load).

Register a loader with tanzim::Config::with_loader; it’s dispatched by the source strings its supported_source_list() returns. For a quick, stateless adapter, use closure::Closure instead of a full impl Load. See the Load rustdoc for worked details.

Built-in loaders

Module	Feature	Source string
env	env	env
file	file	file
http	http	http
closure	—	any (user-defined)

Example

use std::env;
use tanzim_load::{env::Env, Error, Load, Source};

fn main() -> Result<(), Error> {
    // SAFETY: example-only; single-threaded doctest env vars.
    unsafe {
        env::set_var("MY_APP_CFG.DEBUG", "true");
        env::set_var("MY_APP_CFG.NAME", "hello");
        env::set_var("MY_APP_CFG.DATABASE.HOST", "localhost");
    }

    let source = Source::parse(r#"env(prefix=MY_APP_,separator=".")"#).unwrap();

    let payloads = Env::new().load(source)?;
    assert_eq!(payloads.len(), 1);

    let payload = payloads[0].clone();
    assert_eq!(payload.maybe_name, Some("cfg".into()));
    assert_eq!(payload.maybe_format, Some("env".into()));

    let content = String::from_utf8_lossy(&payload.content);
    assert!(content.contains("DEBUG=\"true\""));
    assert!(content.contains("NAME=\"hello\""));
    assert!(content.contains("DATABASE.HOST=\"localhost\""));

    Ok(())
}

Features

Feature	Enables
env	env loader (reads environment variables)
file	file loader (reads from filesystem)
http	http loader (user-provided fetch closure)
logging	emit log messages via the log crate
tracing	emit trace spans via the tracing crate
full	env + file + http

Default features: env, file, http. Logging/tracing are opt-in.

Relations

• Depends on tanzim-source for Source and Options.
• Produces Payload values consumed by tanzim-parse.
• Full pipeline wired in tanzim.

Modules

closure

Custom loader backed by a closure.

env

Environment-variable loader (env feature).

file

Filesystem loader (file feature).

http

HTTP loader (http feature).

Structs

Options

Ordered map of loader options.

Payload

Raw bytes for one configuration entry, with its declaring Source.

Source

One configuration source declaration.

Enums

Error

Errors a Load implementation can return.

OptionValue

Dynamically typed loader option or nested option map.

Traits

Load

Loads raw configuration bytes from a declared source.