datafusion-examples/examples/proto/main.rs

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//! # Examples demonstrating DataFusion's plan serialization via the `datafusion-proto` crate
//!
//! These examples show how to use multiple extension codecs for serialization / deserialization.
//!
//! ## Usage
//! ```bash
//! cargo run --example proto -- [composed_extension_codec]
//! ```
//!
//! Each subcommand runs a corresponding example:
//! - `composed_extension_codec` — example of using multiple extension codecs for serialization / deserialization

mod composed_extension_codec;

use std::str::FromStr;

use datafusion::error::{DataFusionError, Result};

enum ExampleKind {
    ComposedExtensionCodec,
}

impl AsRef<str> for ExampleKind {
    fn as_ref(&self) -> &str {
        match self {
            Self::ComposedExtensionCodec => "composed_extension_codec",
        }
    }
}

impl FromStr for ExampleKind {
    type Err = DataFusionError;

    fn from_str(s: &str) -> Result<Self> {
        match s {
            "composed_extension_codec" => Ok(Self::ComposedExtensionCodec),
            _ => Err(DataFusionError::Execution(format!("Unknown example: {s}"))),
        }
    }
}

impl ExampleKind {
    const ALL: [Self; 1] = [Self::ComposedExtensionCodec];

    const EXAMPLE_NAME: &str = "proto";

    fn variants() -> Vec<&'static str> {
        Self::ALL.iter().map(|x| x.as_ref()).collect()
    }
}

#[tokio::main]
async fn main() -> Result<()> {
    let usage = format!(
        "Usage: cargo run --example {} -- [{}]",
        ExampleKind::EXAMPLE_NAME,
        ExampleKind::variants().join("|")
    );

    let arg = std::env::args().nth(1).ok_or_else(|| {
        eprintln!("{usage}");
        DataFusionError::Execution("Missing argument".to_string())
    })?;

    match arg.parse::<ExampleKind>()? {
        ExampleKind::ComposedExtensionCodec => {
            composed_extension_codec::composed_extension_codec().await?
        }
    }

    Ok(())
}