fix(logger): properly filter tracing-log entries

CHANGELOG.md

@@ -12,6 +12,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 [#107]: https://github.com/elfo-rs/elfo/pull/107
 
+### Fixed
+- logger: `tracing-log` events are now properly filtered by target when `tracing-log` feature is enabled ([#106]).
+
+[#106]: https://github.com/elfo-rs/elfo/pull/106
+
 ## [0.2.0-alpha.7] - 2023-08-11
 ### Fixed
 - supervisor: deadlock if a router returns `Outcome::Multicast` ([#105]).

elfo-logger/Cargo.toml

@@ -10,11 +10,15 @@ license.workspace = true
 edition.workspace = true
 readme.workspace = true
 
+[features]
+tracing-log = [ "dep:tracing-log", "log" ]
+
 [dependencies]
 elfo-core = { version = "0.2.0-alpha.7", path = "../elfo-core", features = ["unstable"] }
 elfo-utils = { version = "0.2.3", path = "../elfo-utils" }
 
 arc-swap = "1.2.0"
+once_cell = { version = "1.8.0", features = ["parking_lot"] }
 derive_more = "0.99.11"
 futures-intrusive = "0.5"
 tokio = { version = "1.5", features = ["macros", "fs", "io-util"] }
@@ -24,6 +28,8 @@ parking_lot = "0.12"
 sharded-slab = "0.1.1"
 tracing = "0.1.25"
 tracing-subscriber = { version = "0.3.2", features = ["env-filter", "parking_lot"] }
+tracing-log = { version = "0.1.3", optional = true }
+log = { version = "0.4.20", optional = true }
 metrics = "0.17"
 dashmap = "5"
 fxhash = "0.2.1"

elfo-logger/src/filtering_layer.rs

@@ -2,6 +2,8 @@ use std::sync::Arc;
 
 use arc_swap::ArcSwap;
 use fxhash::FxHashMap;
+#[cfg(feature = "tracing-log")]
+use once_cell::sync::OnceCell;
 use tracing::{metadata::LevelFilter, subscriber::Interest, Metadata, Subscriber};
 use tracing_subscriber::{
     filter::Targets,
@@ -27,6 +29,8 @@ impl Default for FilteringConfig {
 
 struct Inner {
     config: ArcSwap<FilteringConfig>,
+    #[cfg(feature = "tracing-log")]
+    log_metadata_name: OnceCell<&'static str>,
 }
 
 #[derive(Clone)]
@@ -39,6 +43,8 @@ impl FilteringLayer {
         Self {
             inner: Arc::new(Inner {
                 config: ArcSwap::new(Arc::new(FilteringConfig::default())),
+                #[cfg(feature = "tracing-log")]
+                log_metadata_name: OnceCell::new(),
             }),
         }
     }
@@ -76,6 +82,35 @@ impl<S: Subscriber> Layer<S> for FilteringLayer {
         // We don't need to recheck `.targets` here, because `.register_callsite()`
         // would already eliminate logs that would be filtered by it.
         let level = *meta.level();
+
+        #[cfg(feature = "tracing-log")]
+        {
+            // `tracing-log` doesn't call `.register_callsite()`, so we have to recheck
+            // `.targets` in this one case.
+            let name = meta.name();
+            if let Some(&log_name) = self.inner.log_metadata_name.get() {
+                // We've already got logs from `tracing-log`, just compare str
+                // pointers for performance.
+                if std::ptr::eq(log_name, name) {
+                    let config = self.inner.config.load();
+                    if !config.targets.would_enable(meta.target(), meta.level()) {
+                        return false;
+                    }
+                }
+            } else if name == "log record" {
+                let config = self.inner.config.load();
+                if !config.targets.would_enable(meta.target(), meta.level()) {
+                    return false;
+                }
+                // That's "initialized tracing_log adapter" to set `log_metadata_name`, just
+                // ignore it. Any actual logs from `elfo_logger` would use `tracing`.
+                if meta.target() == "elfo_logger" {
+                    self.inner.log_metadata_name.set(name).ok();
+                    return false;
+                }
+            }
+        }
+
         scope::try_with(|scope| {
             if !scope.permissions().is_logging_enabled(level) {
                 return false;

elfo-logger/src/lib.rs

@@ -82,6 +82,19 @@ pub fn init() -> Blueprint {
         install_subscriber(subscriber);
     };
 
+    #[cfg(feature = "tracing-log")]
+    {
+        if let Err(e) = tracing_log::LogTracer::init() {
+            tracing::error!(
+                error = &*e.to_string(),
+                "can't integrate with log adapter, logs produced via `log` crate might be not available",
+            );
+        } else {
+            // Required to initialize `tracing-log` logs detection in `filtering_layer`.
+            log::error!("initialized tracing_log adapter");
+        }
+    }
+
     blueprint
 }
 

elfo/Cargo.toml

@@ -26,6 +26,7 @@ test-util = ["elfo-test", "elfo-core/test-util"]
 network = ["elfo-network"]
 unstable = ["elfo-core/unstable", "elfo-telemeter/unstable" ]
 unstable-stuck-detection = ["elfo-core/unstable-stuck-detection"]
+tracing-log = ["elfo-logger/tracing-log"]
 
 [dependencies]
 elfo-core = { version = "0.2.0-alpha.7", path = "../elfo-core" }