name: api-wide-base-path-with-default-custom-commands description: How to author custom commands for the api-wide-base-path-with-default CLI using the co-generated SDK.
Custom Commands for api-wide-base-path-with-default
Overview
The api-wide-base-path-with-default CLI supports user-authored custom commands that are
compiled into the binary alongside the auto-generated API commands.
Custom commands get a fully-wired SDK client that inherits the CLI's
auth, retries, TLS, base URL, and global headers — zero configuration required.
Architecture
cli/api-wide-base-path-with-default/custom.rs ← Your command handlers (protected by .fernignore)
cli/api-wide-base-path-with-default/sdk_glue.rs ← Generated bridge: sdk_client() + block_on()
cli/api-wide-base-path-with-default/main.rs ← Generated entrypoint (calls custom::register)
api-wide-base-path-with-default-sdk/ ← Co-generated typed SDK crate
api-wide-base-path-with-default-types/ ← Co-generated typed model crate
Adding a Custom Command
1. Edit cli/api-wide-base-path-with-default/custom.rs
This file is protected by .fernignore — fern generate will never
overwrite it. Register commands in the register() function:
use api_wide_base_path_with_default_sdk::api::*;
pub fn register(app: CliApp) -> CliApp {
let app = app.command(
clap::Command::new("widgets-create")
.about("Run widgets widgets-create")
.arg(clap::Arg::new("apiVersion").required(true))
,
|matches, ctx| {
let api_version = matches.get_one::<String>("apiVersion").unwrap();
let client = super::sdk_glue::sdk_client(ctx);
let result = super::sdk_glue::block_on(
client.widgets.widgets_create(api_version),
)?;
println!("{}", serde_json::to_string_pretty(&result).unwrap());
Ok(())
},
);
app
}
Then build and test:
cargo build
api-wide-base-path-with-default widgets-create <apiVersion>
2. Available SDK Clients
The sdk_glue::sdk_client(ctx) call returns a api_wide_base_path_with_default_sdk::api::Client
with the following sub-clients:
| Field | Type | Description |
|---|---|---|
client.widgets |
api_wide_base_path_with_default_sdk::api::WidgetsClient |
widgets operations |
3. Key Patterns
Get the SDK client (execution-sharing, fully authenticated):
let client = super::sdk_glue::sdk_client(ctx);
Run an async SDK call from a sync handler:
let result = super::sdk_glue::block_on(
client.some_resource.some_method(args),
)?;
Use typed models for request/response serialization:
use api_wide_base_path_with_default_sdk::api::*;
Regeneration Safety
| File | Regenerated? | Notes |
|---|---|---|
cli/api-wide-base-path-with-default/custom.rs |
No | Protected by .fernignore |
cli/api-wide-base-path-with-default/sdk_glue.rs |
Yes | Bridges AppContext → SDK client |
cli/api-wide-base-path-with-default/main.rs |
Yes | Calls custom::register(app) |
api-wide-base-path-with-default-sdk/ |
Yes | Co-generated typed SDK crate |
api-wide-base-path-with-default-types/ |
Yes | Co-generated typed models |
After running fern generate, your custom.rs is preserved. All
generated code (SDK, types, glue, main.rs) is updated to match the
latest API spec. If the SDK surface changes (renamed methods, new
sub-clients), update your custom.rs to match.
Build & Test
# Build the CLI (includes custom commands)
cargo build
# Run your custom command
api-wide-base-path-with-default <your-command> [args]
# Run with verbose output for debugging
RUST_LOG=debug api-wide-base-path-with-default <your-command> [args]