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use super::{Node, NodeContext, NodeKind, NodeRequest, NodeResponse};
use crate::{config::DynNode, error::ServiceError};
use anyhow::Result;
use bytes::Bytes;
use futures::{Future, StreamExt};
use http_body_util::{combinators::BoxBody, BodyExt, StreamBody};
use hyper::body::{Body, Frame};
use serde::Deserialize;
use std::{
pin::Pin,
sync::Arc,
time::{Duration, Instant},
};
use tokio::time::sleep_until;
pub struct LimitsKind;
#[derive(Deserialize)]
pub struct Limits {
#[serde(default)]
request: LimitParam,
#[serde(default)]
response: LimitParam,
next: DynNode,
}
#[derive(Debug, Clone, Deserialize, Default)]
struct LimitParam {
size: Option<u64>,
rate: Option<u64>,
rate_buffer: Option<u64>,
}
impl NodeKind for LimitsKind {
fn name(&self) -> &'static str {
"limits"
}
fn instanciate(&self, config: serde_yml::Value) -> Result<Arc<dyn Node>> {
Ok(Arc::new(serde_yml::from_value::<Limits>(config)?))
}
}
impl Node for Limits {
fn handle<'a>(
&'a self,
context: &'a mut NodeContext,
request: NodeRequest,
) -> Pin<Box<dyn Future<Output = Result<NodeResponse, ServiceError>> + Send + Sync + 'a>> {
Box::pin(async move {
let request = request.map(|body| limit_body(body, self.request.clone()).boxed());
let response = self.next.handle(context, request).await?;
Ok(response.map(|body| limit_body(body, self.response.clone()).boxed()))
})
}
}
fn limit_body(
inner: BoxBody<Bytes, ServiceError>,
config: LimitParam,
) -> impl Body<Data = Bytes, Error = ServiceError> {
let mut stream = inner.into_data_stream();
let mut state = State::new(config);
StreamBody::new(async_stream::stream! {
while let Some(k) = stream.next().await {
match k {
Ok(data) => {
if state.update(data.len()).await {
yield Ok(Frame::data(data))
} else {
break;
}
},
Err(e) => yield Err(e)
}
}
})
}
struct State {
config: LimitParam,
last_read: Instant,
size: u64,
}
impl State {
pub fn new(config: LimitParam) -> Self {
Self {
config,
last_read: Instant::now(),
size: 0,
}
}
pub async fn update(&mut self, len: usize) -> bool {
if let Some(rate) = self.config.rate {
let buffer = Duration::from_millis(self.config.rate_buffer.unwrap_or(1000));
let el = self.last_read.elapsed();
if el > buffer {
self.last_read += el - buffer
}
self.last_read += Duration::from_nanos((len as u64 * 1_000_000_000) / rate);
sleep_until(self.last_read.into()).await
}
if let Some(max_size) = self.config.size {
self.size += len as u64;
self.size < max_size
} else {
true
}
}
}
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