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 -- [all|composed_extension_codec|expression_deduplication]
//! ```
//!
//! Each subcommand runs a corresponding example:
//! - `all` — run all examples included in this module
//!
//! - `composed_extension_codec`
//!   (file: composed_extension_codec.rs, desc: Use multiple extension codecs for serialization/deserialization)
//!
//! - `expression_deduplication`
//!   (file: expression_deduplication.rs, desc: Example of expression caching/deduplication using the codec decorator pattern)

mod composed_extension_codec;
mod expression_deduplication;

use datafusion::error::{DataFusionError, Result};
use strum::{IntoEnumIterator, VariantNames};
use strum_macros::{Display, EnumIter, EnumString, VariantNames};

#[derive(EnumIter, EnumString, Display, VariantNames)]
#[strum(serialize_all = "snake_case")]
enum ExampleKind {
    All,
    ComposedExtensionCodec,
    ExpressionDeduplication,
}

impl ExampleKind {
    const EXAMPLE_NAME: &str = "proto";

    fn runnable() -> impl Iterator<Item = ExampleKind> {
        ExampleKind::iter().filter(|v| !matches!(v, ExampleKind::All))
    }

    async fn run(&self) -> Result<()> {
        match self {
            ExampleKind::All => {
                for example in ExampleKind::runnable() {
                    println!("Running example: {example}");
                    Box::pin(example.run()).await?;
                }
            }
            ExampleKind::ComposedExtensionCodec => {
                composed_extension_codec::composed_extension_codec().await?
            }
            ExampleKind::ExpressionDeduplication => {
                expression_deduplication::expression_deduplication().await?
            }
        }
        Ok(())
    }
}

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

    let example: ExampleKind = std::env::args()
        .nth(1)
        .unwrap_or_else(|| ExampleKind::All.to_string())
        .parse()
        .map_err(|_| DataFusionError::Execution(format!("Unknown example. {usage}")))?;

    example.run().await
}