add support for logging to a file

Author: br0kenpixel

README.md

@@ -44,6 +44,14 @@ rate_limiter:
   max_requests: 4
   # Maximum amount of connections that may be accepted within the specified time frame above.
   max_connections: 4
+
+# Logging configuration
+logging:
+  # Path to the log file, or null to disable
+  file: "/var/log/pwmp-server.log" # or null to disable
+
+  # Whether to erase the log file on start
+  erase_file_on_start: false
 ```
 
 ## Database server

src/error.rs

@@ -77,4 +77,12 @@ pub enum Error {
     /// Failed to get current username.
     #[error("Failed to get current username: {0}")]
     Whoami(#[from] whoami::Error),
+
+    /// Configuration load/store error.
+    #[error("confy: {0}")]
+    Config(#[from] confy::ConfyError),
+
+    /// The log file path is not absolute.
+    #[error("Path to the log file must be absolute")]
+    IllegalLogfilePath,
 }

src/logging.rs

@@ -1,9 +1,13 @@
-use crate::error::Error;
-use std::time::SystemTime;
+use crate::{error::Error, server::config::Config};
+use std::{fs, time::SystemTime};
 use tracing::level_filters::LevelFilter;
-use tracing_subscriber::fmt::{
-    format::{FmtSpan, Writer},
-    time::FormatTime,
+use tracing_subscriber::{
+    fmt::{
+        format::{FmtSpan, Writer},
+        time::FormatTime,
+    },
+    layer::SubscriberExt,
+    util::SubscriberInitExt,
 };
 
 struct DateTimeFormatter;
@@ -16,21 +20,49 @@ impl FormatTime for DateTimeFormatter {
     }
 }
 
-pub fn setup(debug: bool) -> Result<(), Error> {
-    let level = if cfg!(debug_assertions) | debug {
+pub fn setup(force_debug: bool, config: &Config) -> Result<(), Error> {
+    let level = if cfg!(debug_assertions) | force_debug {
         LevelFilter::DEBUG
     } else {
         LevelFilter::INFO
     };
 
-    let subscriber = tracing_subscriber::fmt()
+    let file_layer = if let Some(path) = &config.logging.file {
+        if !path.is_absolute() {
+            return Err(Error::IllegalLogfilePath);
+        }
+
+        let file = fs::OpenOptions::new()
+            .create(true)
+            .write(true)
+            .truncate(config.logging.erase_file_on_start)
+            .append(!config.logging.erase_file_on_start)
+            .open(path)?;
+
+        let file_layer = tracing_subscriber::fmt::layer()
+            .with_writer(file)
+            .with_ansi(false)
+            .compact()
+            .with_timer(DateTimeFormatter)
+            .with_target(false)
+            .with_span_events(FmtSpan::CLOSE);
+
+        Some(file_layer)
+    } else {
+        None
+    };
+
+    let stdout_layer = tracing_subscriber::fmt::layer()
         .compact()
         .with_timer(DateTimeFormatter)
         .with_target(false)
-        .with_max_level(level)
-        .with_span_events(FmtSpan::CLOSE)
-        .finish();
-    tracing::subscriber::set_global_default(subscriber)?;
+        .with_span_events(FmtSpan::CLOSE);
+
+    tracing_subscriber::registry()
+        .with(stdout_layer)
+        .with(file_layer)
+        .with(level)
+        .init();
 
     Ok(())
 }

src/main.rs

@@ -2,8 +2,7 @@ use clap::Parser;
 use cli::Command;
 use server::config::Config;
 use sqlx::migrate::Migrator;
-use std::process::exit;
-use tracing::{debug, error, info};
+use tracing::{debug, info};
 
 mod cli;
 mod dbmgr;
@@ -18,24 +17,14 @@ pub static MIGRATOR: Migrator = sqlx::migrate!();
 #[tokio::main]
 async fn main() -> Result<(), error::Error> {
     let args = cli::Cli::parse();
+    let config_path = args.config.clone().unwrap_or_else(Config::default_path);
+    let (config, first_run) = server::config::setup(&config_path)?;
 
-    logging::setup(args.debug)?;
+    logging::setup(args.debug, &config)?;
 
     info!("PixelWeather Server v{}", env!("CARGO_PKG_VERSION"));
     debug!("Arguments: {args:?}");
 
-    let config_path = args.config.unwrap_or_else(Config::default_path);
-    info!("Loading config from {}", config_path.display());
-
-    let first_run = !config_path.exists();
-    let config: Config = match confy::load_path(&config_path) {
-        Ok(config) => config,
-        Err(why) => {
-            error!("Failed to load configuration: {why}");
-            exit(1);
-        }
-    };
-
     if first_run {
         info!("Configuration initialized at {}", config_path.display());
         return Ok(());

src/server/config.rs

@@ -8,6 +8,8 @@ use std::{
     time::Duration,
 };
 
+use crate::error::Error;
+
 #[serde_as]
 #[derive(Debug, Serialize, Deserialize, Default)]
 pub struct Config {
@@ -16,6 +18,7 @@ pub struct Config {
     pub limits: LimitsConfig,
     #[serde(rename = "rate_limiter")]
     pub rate_limits: RateLimitConfig,
+    pub logging: LogConfig,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -51,6 +54,12 @@ pub struct RateLimitConfig {
     pub max_connections: usize,
 }
 
+#[derive(Debug, Serialize, Deserialize, Default)]
+pub struct LogConfig {
+    pub file: Option<PathBuf>,
+    pub erase_file_on_start: bool,
+}
+
 impl Default for RateLimitConfig {
     fn default() -> Self {
         Self {
@@ -106,3 +115,10 @@ impl Config {
         SocketAddrV4::new(self.server.host, self.server.port)
     }
 }
+
+pub fn setup(config_path: &PathBuf) -> Result<(Config, bool), Error> {
+    let first_run = !config_path.exists();
+    let config: Config = confy::load_path(config_path)?;
+
+    Ok((config, first_run))
+}