From 97364241421999965813e1c4e4a82037efc1adf8 Mon Sep 17 00:00:00 2001
From: Tamo <tamo@meilisearch.com>
Date: Thu, 25 Jan 2024 18:09:50 +0100
Subject: [PATCH] WIP: first draft at introducing a new log route

---
 meilisearch/src/routes/logs.rs | 137 +++++++++++++++++++++++++++++++++
 meilisearch/src/routes/mod.rs  |   2 +
 2 files changed, 139 insertions(+)
 create mode 100644 meilisearch/src/routes/logs.rs

diff --git a/meilisearch/src/routes/logs.rs b/meilisearch/src/routes/logs.rs
new file mode 100644
index 000000000..3201fc5b7
--- /dev/null
+++ b/meilisearch/src/routes/logs.rs
@@ -0,0 +1,137 @@
+use std::fmt;
+use std::io::Write;
+use std::pin::Pin;
+use std::str::FromStr;
+use std::task::Poll;
+
+use actix_web::web::{Bytes, Data};
+use actix_web::{web, HttpRequest, HttpResponse};
+use deserr::actix_web::AwebJson;
+use deserr::Deserr;
+use futures_util::{pin_mut, FutureExt};
+use meilisearch_auth::AuthController;
+use meilisearch_types::deserr::DeserrJsonError;
+use meilisearch_types::error::deserr_codes::*;
+use meilisearch_types::error::ResponseError;
+use tokio::pin;
+use tokio::sync::mpsc;
+use tracing_subscriber::layer::SubscriberExt;
+use tracing_subscriber::Layer;
+
+use crate::extractors::authentication::policies::*;
+use crate::extractors::authentication::GuardedData;
+use crate::extractors::sequential_extractor::SeqHandler;
+
+pub fn configure(cfg: &mut web::ServiceConfig) {
+    cfg.service(web::resource("").route(web::post().to(SeqHandler(get_logs))));
+}
+
+#[derive(Debug, Default, Clone, Copy, Deserr)]
+#[serde(rename_all = "lowercase")]
+pub enum LogLevel {
+    Error,
+    Warn,
+    #[default]
+    Info,
+    Debug,
+    Trace,
+}
+
+#[derive(Debug, Deserr)]
+#[deserr(error = DeserrJsonError, rename_all = camelCase, deny_unknown_fields)]
+pub struct GetLogs {
+    #[deserr(default, error = DeserrJsonError<BadRequest>)]
+    pub level: LogLevel,
+}
+
+impl fmt::Display for LogLevel {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            LogLevel::Error => f.write_str("error"),
+            LogLevel::Warn => f.write_str("warn"),
+            LogLevel::Info => f.write_str("info"),
+            LogLevel::Debug => f.write_str("debug"),
+            LogLevel::Trace => f.write_str("trace"),
+        }
+    }
+}
+
+struct LogWriter {
+    sender: mpsc::UnboundedSender<Vec<u8>>,
+}
+
+impl Write for LogWriter {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.sender.send(buf.to_vec()).map_err(std::io::Error::other)?;
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+struct LogStreamer {
+    receiver: mpsc::UnboundedReceiver<Vec<u8>>,
+    // We just need to hold the guard until the struct is dropped
+    #[allow(unused)]
+    subscriber: tracing::subscriber::DefaultGuard,
+}
+
+impl futures_util::Stream for LogStreamer {
+    type Item = Result<Bytes, ResponseError>;
+
+    fn poll_next(
+        self: Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> Poll<Option<Self::Item>> {
+        let future = self.get_mut().receiver.recv();
+        pin_mut!(future);
+
+        match future.poll_unpin(cx) {
+            std::task::Poll::Ready(recv) => match recv {
+                Some(buf) => {
+                    // let bytes = Bytes::copy_from_slice(buf.as_slice());
+                    Poll::Ready(Some(Ok(buf.into())))
+                }
+                None => Poll::Ready(None),
+            },
+            Poll::Pending => Poll::Pending,
+        }
+    }
+}
+
+pub async fn get_logs(
+    _auth_controller: GuardedData<ActionPolicy<{ actions::METRICS_ALL }>, Data<AuthController>>,
+    body: AwebJson<GetLogs, DeserrJsonError>,
+    _req: HttpRequest,
+) -> Result<HttpResponse, ResponseError> {
+    let opt = body.into_inner();
+
+    // #[cfg(not(feature = "stats_alloc"))]
+    // let (mut trace, layer) = tracing_trace::Trace::new(file);
+    // #[cfg(feature = "stats_alloc")]
+    // let (mut trace, layer) = tracing_trace::Trace::with_stats_alloc(file, &ALLOC);
+
+    let (sender, receiver) = tokio::sync::mpsc::unbounded_channel();
+
+    let subscriber = tracing_subscriber::registry().with(
+        tracing_subscriber::fmt::layer()
+            .with_line_number(true)
+            .with_writer(move || LogWriter { sender: sender.clone() })
+            .with_span_events(tracing_subscriber::fmt::format::FmtSpan::ACTIVE)
+            .with_filter(
+                tracing_subscriber::filter::LevelFilter::from_str(&opt.level.to_string()).unwrap(),
+            ),
+    );
+    // .with(
+    //     layer.with_filter(
+    //         tracing_subscriber::filter::Targets::new()
+    //             .with_target("indexing::", tracing::Level::TRACE),
+    //     ),
+    // );
+
+    let subscriber = tracing::subscriber::set_default(subscriber);
+
+    Ok(HttpResponse::Ok().streaming(LogStreamer { receiver, subscriber }))
+}
diff --git a/meilisearch/src/routes/mod.rs b/meilisearch/src/routes/mod.rs
index 0e5623b09..546c5e219 100644
--- a/meilisearch/src/routes/mod.rs
+++ b/meilisearch/src/routes/mod.rs
@@ -22,6 +22,7 @@ mod api_key;
 mod dump;
 pub mod features;
 pub mod indexes;
+mod logs;
 mod metrics;
 mod multi_search;
 mod snapshot;
@@ -31,6 +32,7 @@ pub mod tasks;
 pub fn configure(cfg: &mut web::ServiceConfig) {
     cfg.service(web::scope("/tasks").configure(tasks::configure))
         .service(web::resource("/health").route(web::get().to(get_health)))
+        .service(web::scope("/logs").configure(logs::configure))
         .service(web::scope("/keys").configure(api_key::configure))
         .service(web::scope("/dumps").configure(dump::configure))
         .service(web::scope("/snapshots").configure(snapshot::configure))