14 implement logger initialization logic (#15)

* add backend

* post review fixes pt.1

* post review fixes pt.2

* remove wrappers

* post review fixes (WIP)

* change build flow + error handling

* log4rs add (WIP)

* add loggers

* clean up

* remove dep

* remove stderr target

* delete stderr target + unify trace-level

* delete redundant lock file

* clean up

* logger init rework

* post review fixes + error_stack errors

* adjust fixes

* replace write check with is_empty check

* Update backend/src/config.rs

* Update backend/src/config.rs

CHANGELOG.md

@@ -5,8 +5,8 @@ Bob Management GUI changelog
 ## [Unreleased]
 
 #### Added
-
 - Initial project structure, backend only (#9)
 - Initial project stricture, frontend (#10)
 - Dockerfile and Docker-Compose to simplify deployment (#5)
 - CI/CD configuration (#11)
+- Logger Initialization (#14)

backend/Cargo.toml

@@ -22,6 +22,8 @@ tower-http = { version = "0.4", features = ["cors", "fs"] }
 
 ## Logging
 tracing = "0.1"
+file-rotate = "0.7"
+tracing-appender = "0.2"
 tracing-subscriber = "0.3"
 
 ## Error Handling

backend/src/config.rs

@@ -1,16 +1,158 @@
-use cli::Config;
+use crate::prelude::*;
+use cli::{Config, LoggerConfig};
+use file_rotate::{suffix::AppendTimestamp, ContentLimit, FileRotate};
+use thiserror::Error;
 use tower_http::cors::CorsLayer;
+use tracing_appender::non_blocking::{NonBlocking, WorkerGuard};
+use tracing_subscriber::{filter::LevelFilter, prelude::*, util::SubscriberInitExt};
 
+#[allow(clippy::module_name_repetitions)]
 pub trait ConfigExt {
     /// Return either very permissive [`CORS`](`CorsLayer`) configuration
     /// or empty one based on `cors_allow_all` field
     fn get_cors_configuration(&self) -> CorsLayer;
 }
 
+pub trait LoggerExt {
+    /// Initialize logger.
+    ///
+    /// Returns [`WorkerGuard`]s for off-thread writers.
+    /// Should not be dropped.
+    ///
+    /// # Errors
+    ///
+    /// Function returns error if `init_file_rotate` fails
+    fn init_logger(&self) -> Result<Vec<WorkerGuard>, LoggerError>;
+
+    /// Returns [`std:io::Write`] object that rotates files on write
+    ///
+    /// # Errors
+    ///
+    /// Function returns error if `log_file` is not specified
+    fn init_file_rotate(&self) -> Result<FileRotate<AppendTimestamp>, LoggerError>;
+
+    /// Returns non-blocking file writer
+    ///
+    /// Also returns [`WorkerGuard`] for off-thread writing.
+    /// Should not be dropped.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if the file logger configuration is empty, file logging
+    /// is disabled or logs filename is not specified
+    fn non_blocking_file_writer(&self) -> Result<(NonBlocking, WorkerGuard), LoggerError>;
+
+    /// Returns non-blocking stdout writer
+    ///
+    /// Also returns [`WorkerGuard`] for off-thread writing.
+    /// Should not be dropped.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if the stdout logger configuration is empty or stdout logging
+    /// is disabled
+    fn non_blocking_stdout_writer(&self) -> Result<(NonBlocking, WorkerGuard), LoggerError>;
+}
+
 impl ConfigExt for Config {
     fn get_cors_configuration(&self) -> CorsLayer {
         self.cors_allow_all
             .then_some(CorsLayer::very_permissive())
             .unwrap_or_default()
     }
 }
+
+impl LoggerExt for LoggerConfig {
+    fn init_logger(&self) -> Result<Vec<WorkerGuard>, LoggerError> {
+        let mut guards = Vec::with_capacity(2);
+
+        let file_writer = disable_on_error(self.non_blocking_file_writer())?;
+        let stdout_writer = disable_on_error(self.non_blocking_stdout_writer())?;
+
+        let mut layers_iter =
+            [file_writer, stdout_writer]
+                .into_iter()
+                .flatten()
+                .map(|(writer, guard)| {
+                    guards.push(guard);
+                    tracing_subscriber::fmt::layer()
+                        .with_writer(writer)
+                        .with_filter(LevelFilter::from_level(self.trace_level))
+                });
+
+        if let Some(first_layer) = layers_iter.next() {
+            tracing_subscriber::registry()
+                .with(layers_iter.fold(first_layer.boxed(), |layer, next_layer| {
+                    layer.and_then(next_layer).boxed()
+                }))
+                .init();
+        };
+
+        Ok(guards)
+    }
+
+    fn init_file_rotate(&self) -> Result<FileRotate<AppendTimestamp>, LoggerError> {
+        let config = self.file.as_ref().ok_or(LoggerError::EmptyConfig)?;
+        let log_file = config.log_file.as_ref().ok_or(LoggerError::NoFileName)?;
+        if log_file.as_os_str().is_empty() {
+            return Err(LoggerError::NoFileName.into());
+        }
+
+        Ok(FileRotate::new(
+            log_file,
+            AppendTimestamp::default(file_rotate::suffix::FileLimit::MaxFiles(config.log_amount)),
+            ContentLimit::BytesSurpassed(config.log_size),
+            file_rotate::compression::Compression::OnRotate(1),
+            None,
+        ))
+    }
+
+    fn non_blocking_file_writer(&self) -> Result<(NonBlocking, WorkerGuard), LoggerError> {
+        self.file.as_ref().map_or_else(
+            || Err(LoggerError::EmptyConfig.into()),
+            |config| {
+                if config.enabled {
+                    Ok(tracing_appender::non_blocking(self.init_file_rotate()?))
+                } else {
+                    Err(LoggerError::NotEnabled.into())
+                }
+            },
+        )
+    }
+
+    fn non_blocking_stdout_writer(&self) -> Result<(NonBlocking, WorkerGuard), LoggerError> {
+        self.stdout.as_ref().map_or_else(
+            || Err(LoggerError::EmptyConfig.into()),
+            |config| {
+                if config.enabled {
+                    Ok(tracing_appender::non_blocking(std::io::stdout()))
+                } else {
+                    Err(LoggerError::NotEnabled.into())
+                }
+            },
+        )
+    }
+}
+
+#[derive(Debug, Error)]
+pub enum LoggerError {
+    #[error("Empty logger configuration")]
+    EmptyConfig,
+    #[error("No filename specified")]
+    NoFileName,
+    #[error("This logger is not enabled")]
+    NotEnabled,
+}
+
+/// Consume some errors to produce empty logger
+fn disable_on_error(
+    logger: Result<(NonBlocking, WorkerGuard), LoggerError>,
+) -> Result<Option<(NonBlocking, WorkerGuard)>, LoggerError> {
+    Ok(match logger {
+        Ok(writer) => Some(writer),
+        Err(e) => match e.current_context() {
+            LoggerError::NotEnabled | LoggerError::EmptyConfig => None,
+            _ => return Err(e),
+        },
+    })
+}

backend/src/lib.rs

@@ -4,7 +4,6 @@
 use axum::{routing::get, Router};
 
 use utoipa::OpenApi;
-
 pub mod config;
 pub mod connector;
 pub mod error;

backend/src/main.rs

@@ -1,8 +1,12 @@
-#![allow(clippy::multiple_crate_versions)]
+#![allow(
+    clippy::multiple_crate_versions,
+    clippy::unwrap_used,
+    clippy::expect_used
+)]
 
 use axum::Router;
 use bob_management::{
-    config::ConfigExt,
+    config::{ConfigExt, LoggerExt},
     prelude::*,
     root,
     router::{ApiV1, ApiVersion, NoApi, RouterApiExt},
@@ -12,23 +16,21 @@ use bob_management::{
 use cli::Parser;
 use error_stack::{Result, ResultExt};
 use hyper::Method;
-use std::{env, path::PathBuf};
+use std::env;
 use tower::ServiceBuilder;
 use tower_http::{cors::CorsLayer, services::ServeDir};
-use tracing::Level;
 
 const FRONTEND_FOLDER: &str = "frontend";
 
 #[tokio::main]
-#[allow(clippy::unwrap_used, clippy::expect_used)]
 async fn main() -> Result<(), AppError> {
     let config = cli::Config::try_from(cli::Args::parse())
         .change_context(AppError::InitializationError)
         .attach_printable("Couldn't get config file.")?;
 
     let logger = &config.logger;
 
-    init_tracer(&logger.log_file, logger.trace_level);
+    let _guard = logger.init_logger().unwrap();
     tracing::info!("Logger: {logger:?}");
 
     let cors: CorsLayer = config.get_cors_configuration();
@@ -50,11 +52,6 @@ async fn main() -> Result<(), AppError> {
     Ok(())
 }
 
-fn init_tracer(_log_file: &Option<PathBuf>, trace_level: Level) {
-    let subscriber = tracing_subscriber::fmt().with_max_level(trace_level);
-    subscriber.init();
-}
-
 #[allow(clippy::unwrap_used, clippy::expect_used)]
 fn router(cors: CorsLayer) -> Router {
     let mut frontend = env::current_exe().expect("Couldn't get current executable path.");

cli/src/config.rs

@@ -26,28 +26,53 @@ pub struct Config {
 }
 
 /// Logger Configuration passed on initialization
-#[allow(clippy::module_name_repetitions)]
 #[serde_as]
 #[derive(Clone, Debug, Deserialize)]
 #[serde(rename_all = "kebab-case")]
 pub struct LoggerConfig {
-    /// [Stub] File to save logs
-    pub log_file: Option<PathBuf>,
-
-    /// [Stub] Number of log files
-    #[serde(default = "LoggerConfig::default_log_amount")]
-    pub log_amount: usize,
+    /// Rolling file logger config
+    #[serde(default)]
+    pub file: Option<FileLogger>,
 
-    /// [Stub] Max size of a single log file, in bytes
-    #[serde(default = "LoggerConfig::default_log_size")]
-    pub log_size: u64,
+    /// Stdout logger config
+    #[serde(default)]
+    pub stdout: Option<StdoutLogger>,
 
     /// Tracing Level
-    #[serde(default = "LoggerConfig::tracing_default")]
+    #[serde(default = "LoggerConfig::level_default")]
     #[serde_as(as = "DisplayFromStr")]
     pub trace_level: tracing::Level,
 }
 
+/// File Logger Configuration for writing logs to files
+#[serde_as]
+#[derive(Clone, Debug, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub struct FileLogger {
+    /// Enable log output to file
+    pub enabled: bool,
+
+    /// File to save logs
+    pub log_file: Option<PathBuf>,
+
+    /// Number of log files
+    #[serde(default = "FileLogger::default_log_amount")]
+    pub log_amount: usize,
+
+    /// Max size of a single log file, in bytes
+    #[serde(default = "FileLogger::default_log_size")]
+    pub log_size: usize,
+}
+
+/// Stdout Logger Configuration for printing logs into stdout
+#[serde_as]
+#[derive(Clone, Debug, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub struct StdoutLogger {
+    /// Enable log output to stdout
+    pub enabled: bool,
+}
+
 impl Default for Config {
     fn default() -> Self {
         Self {
@@ -59,41 +84,77 @@ impl Default for Config {
     }
 }
 
+impl Default for LoggerConfig {
+    fn default() -> Self {
+        Self {
+            file: None,
+            stdout: None,
+            trace_level: Self::level_default(),
+        }
+    }
+}
+
 impl Config {
+    #[must_use]
     pub const fn default_cors() -> bool {
         false
     }
 
+    #[must_use]
     pub const fn default_timeout() -> Duration {
         Duration::from_millis(5000)
     }
 }
 
 impl LoggerConfig {
-    pub const fn tracing_default() -> tracing::Level {
-        tracing::Level::INFO
+    #[must_use]
+    pub const fn level_default() -> tracing::Level {
+        tracing::Level::TRACE
+    }
+}
+
+impl FileLogger {
+    #[must_use]
+    pub const fn default_enabled() -> bool {
+        false
     }
 
+    #[must_use]
     pub const fn default_log_amount() -> usize {
         5
     }
 
-    pub const fn default_log_size() -> u64 {
-        10u64.pow(6)
+    #[must_use]
+    pub const fn default_log_size() -> usize {
+        10usize.pow(6)
     }
 }
 
-impl Default for LoggerConfig {
+impl StdoutLogger {
+    #[must_use]
+    pub const fn default_enabled() -> bool {
+        false
+    }
+}
+
+impl Default for FileLogger {
     fn default() -> Self {
         Self {
             log_file: None,
             log_amount: Self::default_log_amount(),
             log_size: Self::default_log_size(),
-            trace_level: Self::tracing_default(),
+            enabled: Self::default_enabled(),
         }
     }
 }
 
+impl Default for StdoutLogger {
+    fn default() -> Self {
+        Self {
+            enabled: Self::default_enabled(),
+        }
+    }
+}
 pub trait FromFile {
     /// Parses the file spcified in `path`
     ///

cli/src/lib.rs

@@ -3,4 +3,4 @@ mod config;
 
 pub use clap::Parser;
 pub use cli::Args;
-pub use config::{Config, FromFile, LoggerConfig};
+pub use config::{Config, FileLogger, FromFile, LoggerConfig, StdoutLogger};