conjure-runtime 7.3.0

// Copyright 2020 Palantir Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
use crate::rt::time::Instant;
use crate::service::node::Node;
use crate::service::{Layer, Service};
use http::{Request, Response};
use std::sync::Arc;

/// A layer which updates the host metrics for the node stored in the request's extensions map.
pub struct NodeMetricsLayer;

impl<S> Layer<S> for NodeMetricsLayer {
    type Service = NodeMetricsService<S>;

    fn layer(self, inner: S) -> NodeMetricsService<S> {
        NodeMetricsService { inner }
    }
}

pub struct NodeMetricsService<S> {
    inner: S,
}

impl<S, B1, B2> Service<Request<B1>> for NodeMetricsService<S>
where
    S: Service<Request<B1>, Response = Response<B2>>,
{
    type Error = S::Error;
    type Response = S::Response;

    async fn call(&self, req: Request<B1>) -> Result<S::Response, S::Error> {
        let node = req
            .extensions()
            .get::<Arc<Node>>()
            .expect("should have a Node extension")
            .clone();

        let start = Instant::now();
        let result = self.inner.call(req).await;

        if let Some(host_metrics) = &node.host_metrics {
            match &result {
                Ok(response) => host_metrics.update(response.status(), start.elapsed()),
                Err(_) => host_metrics.update_io_error(),
            }
        }

        result
    }
}