Initialization

There are several ways to construct an App, depending on whether your catalog comes from YAML files or is built programmatically.

App::from_yaml + with_args

The most common pattern for file-based pipelines. Loads catalog and params from YAML, then applies CLI arguments:

App::from_yaml("conf/catalog.yml", "conf/params.yml")?
    .with_args(std::env::args_os())?
    .dispatch(pipeline)

from_yaml loads and deserializes both files. with_args parses CLI arguments for subcommand selection and parameter overrides.

Requires std. Catalog and params types must implement DeserializeOwned.

App::from_args

Parses CLI arguments including --catalog-path and --params-path flags:

App::from_args(std::env::args_os())?
    .dispatch(pipeline)

Default paths if not specified: conf/base/catalog.yml and conf/base/parameters.yml.

Requires std.

App::from_cli

Same as from_args but takes a pre-parsed CliArgs struct:

use pondrs::app::cli::CliArgs;
use clap::Parser;

let cli = CliArgs::parse();
App::from_cli(cli)?
    .dispatch(pipeline)

App::new

Construct with catalog and params directly — no YAML, no CLI:

let catalog = Catalog { /* ... */ };
let params = Params { /* ... */ };

App::new(catalog, params)
    .execute(pipeline)?;

This is the only constructor available in no_std. It defaults to Command::Run with no hooks and the default runners.

Use App::new when:

• The catalog is built programmatically (e.g. RegisterDataset, GpioDataset)
• You’re writing tests and want to inspect datasets after execution
• You’re in a no_std environment

You can still add CLI support to a programmatic catalog via with_args:

App::new(catalog, params)
    .with_args(std::env::args_os())?  // adds subcommand + param overrides
    .dispatch(pipeline)?;

Builder methods

After construction, configure the app with builder methods:

App::from_yaml("catalog.yml", "params.yml")?
    .with_args(std::env::args_os())?
    .with_hooks((LoggingHook::new(),))
    .with_runners((SequentialRunner, ParallelRunner))
    .dispatch(pipeline)?;

Execution methods