cardinal_proxy/

lib.rs

pub mod req;
pub mod retry;
mod utils;

use crate::req::ReqCtx;
use crate::retry::RetryState;
use crate::utils::requests::{
    compose_upstream_url, execution_context_from_request, parse_origin, rewrite_request_path,
    set_upstream_host_headers,
};
use bytes::Bytes;
use cardinal_base::context::CardinalContext;
use cardinal_base::destinations::container::DestinationContainer;
use cardinal_config::DestinationRetryBackoffType;
use cardinal_plugins::request_context::{RequestContext, RequestContextBase};
use cardinal_plugins::runner::MiddlewareResult;
use pingora::http::ResponseHeader;
use pingora::prelude::*;
use pingora::protocols::Digest;
use pingora::upstreams::peer::Peer;
use std::sync::Arc;
use std::time::Duration;
use tracing::{debug, error, info, warn};

pub mod pingora {
    pub use pingora::*;
}

#[derive(Debug, Clone)]
pub enum HealthCheckStatus {
    None,
    Ready,
    Unavailable {
        status_code: u16,
        reason: Option<String>,
    },
}

pub trait CardinalContextProvider: Send + Sync {
    fn ctx(&self) -> ReqCtx {
        ReqCtx::default()
    }

    fn resolve(&self, session: &Session, ctx: &mut ReqCtx) -> Option<Arc<CardinalContext>>;
    fn health_check(&self, _session: &Session) -> HealthCheckStatus {
        HealthCheckStatus::None
    }

    fn logging(&self, _session: &mut Session, _e: Option<&Error>, _ctx: &mut ReqCtx) {}
}

#[derive(Clone)]
pub struct StaticContextProvider {
    context: Arc<CardinalContext>,
}

impl StaticContextProvider {
    pub fn new(context: Arc<CardinalContext>) -> Self {
        Self { context }
    }
}

impl CardinalContextProvider for StaticContextProvider {
    fn resolve(&self, _session: &Session, _ctx: &mut ReqCtx) -> Option<Arc<CardinalContext>> {
        Some(self.context.clone())
    }
}

pub struct CardinalProxy {
    provider: Arc<dyn CardinalContextProvider>,
}

impl CardinalProxy {
    pub fn new(context: Arc<CardinalContext>) -> Self {
        Self::builder(context).build()
    }

    pub fn with_provider(provider: Arc<dyn CardinalContextProvider>) -> Self {
        Self { provider }
    }

    pub fn builder(context: Arc<CardinalContext>) -> CardinalProxyBuilder {
        CardinalProxyBuilder::new(context)
    }
}

pub struct CardinalProxyBuilder {
    provider: Arc<dyn CardinalContextProvider>,
}

impl CardinalProxyBuilder {
    pub fn new(context: Arc<CardinalContext>) -> Self {
        Self {
            provider: Arc::new(StaticContextProvider::new(context)),
        }
    }

    pub fn from_context_provider(provider: Arc<dyn CardinalContextProvider>) -> Self {
        Self { provider }
    }

    pub fn with_context_provider(mut self, provider: Arc<dyn CardinalContextProvider>) -> Self {
        self.provider = provider;
        self
    }

    pub fn build(self) -> CardinalProxy {
        CardinalProxy::with_provider(self.provider)
    }
}

#[async_trait::async_trait]
impl ProxyHttp for CardinalProxy {
    type CTX = ReqCtx;

    fn new_ctx(&self) -> Self::CTX {
        self.provider.ctx()
    }

    async fn logging(&self, _session: &mut Session, _e: Option<&Error>, ctx: &mut Self::CTX)
    where
        Self::CTX: Send + Sync,
    {
        self.provider.logging(_session, _e, ctx);
    }

    async fn request_filter(&self, session: &mut Session, ctx: &mut Self::CTX) -> Result<bool> {
        let path = session.req_header().uri.path().to_string();
        info!(%path, "Request received");

        match self.provider.health_check(session) {
            HealthCheckStatus::None => {}
            HealthCheckStatus::Ready => {
                debug!(%path, "Health check ready");
                // Build a 200 OK header
                let mut resp = ResponseHeader::build(200, None)?;
                resp.insert_header("Content-Type", "text/plain")?;
                resp.set_content_length("healthy\n".len())?;

                // Send header + body to the client
                session
                    .write_response_header(Box::new(resp), /*end_of_stream*/ false)
                    .await?;
                session
                    .write_response_body(Some(Bytes::from_static(b"healthy\n")), /*end*/ true)
                    .await?;

                // Returning Ok(true) means "handled", stop further processing.
                return Ok(true);
            }
            HealthCheckStatus::Unavailable {
                status_code,
                reason,
            } => {
                if let Some(reason) = reason {
                    warn!(%path, status = status_code, reason = %reason, "Health check failed");
                } else {
                    warn!(%path, status = status_code, "Health check failed");
                }
                let _ = session.respond_error(status_code).await;
                return Ok(true);
            }
        }

        let context = match self.provider.resolve(session, ctx) {
            Some(ctx) => ctx,
            None => {
                warn!(%path, "No context found for request host");
                let _ = session.respond_error(421).await;
                return Ok(true);
            }
        };

        let destination_container = context
            .get::<DestinationContainer>()
            .await
            .map_err(|_| Error::new_str("Destination Container is not present"))?;

        let force_path = context.config.server.force_path_parameter;
        let backend =
            match destination_container.get_backend_for_request(session.req_header(), force_path) {
                Some(b) => b,
                None => {
                    warn!(%path, "No matching backend, returning 404");
                    let _ = session.respond_error(404).await;
                    return Ok(true);
                }
            };

        let destination_name = backend.destination.name.clone();
        let _ = set_upstream_host_headers(session, &backend);
        info!(backend_id = %destination_name, "Routing to backend");

        rewrite_request_path(session.req_header_mut(), &destination_name, force_path);

        let mut request_state = RequestContext::new(
            context.clone(),
            backend,
            execution_context_from_request(session),
        );

        let plugin_runner = request_state.plugin_runner.clone();

        let run_filters = plugin_runner
            .run_request_filters(session, &mut request_state)
            .await;

        let res = match run_filters {
            Ok(filter_result) => filter_result,
            Err(err) => {
                error!(%err, "Error running request filters");
                let _ = session.respond_error(500).await;
                return Ok(true);
            }
        };

        ctx.set_resolved_request(request_state);

        match res {
            MiddlewareResult::Continue(resp_headers) => {
                ctx.ctx_base
                    .resolved_request
                    .as_mut()
                    .unwrap()
                    .response_headers = Some(resp_headers);

                Ok(false)
            }
            MiddlewareResult::Responded => Ok(true),
        }
    }

    fn fail_to_connect(
        &self,
        _session: &mut Session,
        _peer: &HttpPeer,
        ctx: &mut Self::CTX,
        mut e: Box<Error>,
    ) -> Box<Error> {
        let backend_config = ctx.req_unsafe().backend.destination.retry.clone();
        if let Some(mut retry_state) = ctx.retry_state.take() {
            retry_state.register_attempt();
            if retry_state.can_retry() {
                e.set_retry(true);
                ctx.retry_state = Some(retry_state);
            } else {
                ctx.retry_state = None;
            }
        } else if let Some(retry_config) = backend_config {
            let mut retry_state = RetryState::from(retry_config);
            retry_state.register_attempt();
            if retry_state.can_retry() {
                e.set_retry(true);
                ctx.retry_state = Some(retry_state);
            } else {
                ctx.retry_state = None;
            }
        }

        e
    }

    async fn upstream_peer(
        &self,
        _session: &mut Session,
        ctx: &mut Self::CTX,
    ) -> Result<Box<HttpPeer>> {
        if let Some(retry_state) = ctx.retry_state.as_mut() {
            if !retry_state.sleep_if_retry_allowed().await {
                ctx.retry_state = None;
                return Err(Error::new_str("Retry attempts exhausted"));
            }
        }

        let backend = &ctx.req_unsafe().backend;
        // Determine origin parts for TLS and SNI
        let (host, port, is_tls) = parse_origin(&backend.destination.url)
            .map_err(|_| Error::new_str("Origin could not be parsed "))?;
        let hostport = format!("{host}:{port}");

        // Compose full upstream URL for logging with normalized scheme
        let path_and_query = _session
            .req_header()
            .uri
            .path_and_query()
            .map(|pq| pq.as_str())
            .unwrap_or("/");
        let upstream_url = compose_upstream_url(is_tls, &host, port, path_and_query);

        info!(%upstream_url, backend_id = %&backend.destination.name, is_tls, sni = %host, "Forwarding to upstream");
        debug!(upstream_origin = %hostport, "Connecting to upstream origin");

        let mut peer = HttpPeer::new(&hostport, is_tls, host);
        if let Some(opts) = peer.get_mut_peer_options() {
            // Allow both HTTP/1.1 and HTTP/2 so plain HTTP backends keep working.
            opts.set_http_version(2, 1);
            if let Some(timeout) = &backend.destination.timeout {
                opts.idle_timeout = timeout
                    .idle
                    .as_ref()
                    .map(|idle| Duration::from_millis(*idle));
                opts.write_timeout = timeout
                    .write
                    .as_ref()
                    .map(|idle| Duration::from_millis(*idle));
                opts.total_connection_timeout = timeout
                    .connect
                    .as_ref()
                    .map(|idle| Duration::from_millis(*idle));
                opts.read_timeout = timeout
                    .read
                    .as_ref()
                    .map(|idle| Duration::from_millis(*idle));
            }
        }
        let peer = Box::new(peer);
        Ok(peer)
    }

    async fn connected_to_upstream(
        &self,
        _session: &mut Session,
        reused: bool,
        peer: &HttpPeer,
        #[cfg(unix)] _fd: std::os::unix::io::RawFd,
        #[cfg(windows)] _sock: std::os::windows::io::RawSocket,
        _digest: Option<&Digest>,
        ctx: &mut Self::CTX,
    ) -> Result<()> {
        ctx.retry_state = None;
        let backend_id = ctx.req_unsafe().backend.destination.name.to_string();

        info!(backend_id, reused, peer = %peer, "Connected to upstream");
        Ok(())
    }

    async fn response_filter(
        &self,
        session: &mut Session,
        upstream_response: &mut ResponseHeader,
        ctx: &mut Self::CTX,
    ) -> Result<()> {
        if let Some(resp_headers) = ctx.req_unsafe_mut().response_headers.take() {
            for (key, val) in resp_headers {
                let _ = upstream_response.insert_header(key, val);
            }
        }

        {
            // Run response filters first
            {
                let runner = {
                    let req = ctx.req_unsafe_mut();
                    req.plugin_runner.clone()
                };

                runner
                    .run_response_filters(
                        session,
                        {
                            let req = ctx.req_unsafe_mut();
                            req
                        },
                        upstream_response,
                    )
                    .await;
            }

            ctx.set("status", upstream_response.status.as_str());

            // Safe to get another mutable reference now
            let req = ctx.req_unsafe_mut();

            if !req.cardinal_context.config.server.log_upstream_response {
                return Ok(());
            }

            let status = upstream_response.status.as_u16();
            let location = upstream_response
                .headers
                .get("location")
                .and_then(|v| v.to_str().ok())
                .map(str::to_string);
            let backend_id = &req.backend.destination.name;

            match location {
                Some(loc) => info!(backend_id, status, location = %loc, "Upstream responded"),
                None => info!(backend_id, status, "Upstream responded"),
            }
        }

        Ok(())
    }
}