feat: add a utility to create child logger without magic string of the src

Author: Alenar

mithril-common/src/lib.rs

@@ -57,6 +57,7 @@ pub mod crypto_helper;
 pub mod entities;
 #[macro_use]
 pub mod era;
+pub mod logging;
 pub mod messages;
 pub mod protocol;
 pub mod resource_pool;

mithril-common/src/logging.rs

@@ -0,0 +1,83 @@
+//! Logging utilities for the Mithril project.
+
+use slog::Logger;
+
+/// Extension trait for `slog::Logger`
+pub trait LoggerExtensions {
+    /// Create a new child logger with a `src` key containing the component name.
+    fn new_with_component_name<T>(&self) -> Self;
+}
+
+impl LoggerExtensions for Logger {
+    fn new_with_component_name<T>(&self) -> Self {
+        self.new(slog::o!("src" => component_name::<T>()))
+    }
+}
+
+fn component_name<T>() -> &'static str {
+    let complete_name = std::any::type_name::<T>();
+    complete_name.split("::").last().unwrap_or(complete_name)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::test_utils::{TempDir, TestLogger};
+    use slog::info;
+
+    struct TestStruct;
+    #[allow(
+        dead_code,
+        reason = "A field is needed to add the lifetime but is unused"
+    )]
+    struct TestStructWithLifetime<'a>(&'a str);
+    enum TestEnum {}
+
+    mod test_mod {
+        pub struct ScopedTestStruct;
+        pub enum ScopedTestEnum {}
+    }
+
+    impl TestStruct {
+        fn self_component_name() -> &'static str {
+            component_name::<Self>()
+        }
+    }
+
+    #[test]
+    fn extract_component_name_remove_namespaces() {
+        assert_eq!(component_name::<TestStruct>(), "TestStruct");
+        assert_eq!(component_name::<TestEnum>(), "TestEnum");
+        assert_eq!(
+            component_name::<test_mod::ScopedTestStruct>(),
+            "ScopedTestStruct"
+        );
+        assert_eq!(
+            component_name::<test_mod::ScopedTestEnum>(),
+            "ScopedTestEnum"
+        );
+        assert_eq!(TestStruct::self_component_name(), "TestStruct");
+        assert_eq!(
+            component_name::<TestStructWithLifetime>(),
+            "TestStructWithLifetime"
+        );
+    }
+
+    #[test]
+    fn logger_extension_new_with_component_name() {
+        let log_path =
+            TempDir::create("common_logging", "logger_extension_new_with_component_name")
+                .join("test.log");
+        {
+            let root_logger = TestLogger::file(&log_path);
+            let child_logger = root_logger.new_with_component_name::<TestStruct>();
+            info!(child_logger, "Child log");
+        }
+
+        let logs = std::fs::read_to_string(&log_path).unwrap();
+        assert!(
+            logs.contains("src") && logs.contains("TestStruct"),
+            "log should contain `src` key for `TestStruct` as component name was provided, logs:\n{logs}"
+        );
+    }
+}