flarrow-builtins 0.3.1

flarrow (flow + arrow) is a rust runtime/framework for building dataflow applications.
Documentation 
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use std::time::Duration;

use crate::prelude::*;

/// Simple source node that emits a "tick" message at a specified frequency.
#[derive(Node)]
pub struct Timer {
    pub output: Output<String>,
    pub frequency: f64,
}

#[node(runtime = "default_runtime")]
impl Node for Timer {
    async fn new(
        _: Inputs,
        mut outputs: Outputs,
        _: Queries,
        _: Queryables,
        configuration: serde_yml::Value,
    ) -> Result<Self> {
        let frequency = match configuration.get("frequency") {
            Some(serde_yml::Value::Number(number)) => number.as_f64().unwrap_or(1.0),
            _ => 1.0,
        };

        Ok(Self {
            output: outputs.with("out").await?,
            frequency,
        })
    }

    async fn start(self: Box<Self>) -> Result<()> {
        loop {
            self.output
                .send("tick".to_string())
                .await
                .wrap_err("Failed to send message")?;

            tokio::time::sleep(Duration::from_millis((1000.0 / self.frequency) as u64)).await;
        }
    }
}