Tracing logs

Cargo.toml

@@ -85,6 +85,8 @@ tracing = "0.1"
 tracing-subscriber = "0.3"
 url = "2.4.1"
 zeroize = "1.6"
+trace4rs = "0.5.1"
+literally = "0.1.3"
 
 # Vendored for cross-compilation, see https://github.com/cross-rs/cross/wiki/Recipes#openssl
 openssl = { version = "0.10", features = ["vendored"] }

fendermint/app/Cargo.toml

@@ -33,6 +33,8 @@ tokio = { workspace = true }
 tower-abci = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
+trace4rs = { workspace = true }
+literally = { workspace = true }
 
 fendermint_abci = { path = "../abci" }
 fendermint_app_options = { path = "./options" }

fendermint/app/options/src/lib.rs

@@ -75,6 +75,10 @@ pub struct Options {
     )]
     pub home_dir: PathBuf,
 
+    /// Set a custom directory for ipc log files.
+    #[arg(short = 'l', long, env = "FM_LOG_DIR")]
+    pub log_dir: Option<PathBuf>,
+
     /// Optionally override the default configuration.
     #[arg(short, long, default_value = "dev")]
     pub mode: String,

fendermint/app/src/main.rs

@@ -1,27 +1,28 @@
 // Copyright 2022-2023 Protocol Labs
 // SPDX-License-Identifier: Apache-2.0, MIT
 
-use tracing_subscriber::FmtSubscriber;
+use anyhow::{anyhow, Context};
+use std::path::PathBuf;
+use std::str::FromStr;
+use std::sync::Arc;
+use trace4rs::config::{AppenderId, Policy, Target};
+use trace4rs::{
+    config::{self, Config, Format},
+    Handle,
+};
 
 pub use fendermint_app_options as options;
 pub use fendermint_app_settings as settings;
+use fendermint_app_settings::expand_tilde;
 
 mod cmd;
 
 #[tokio::main]
 async fn main() {
     let opts = options::parse();
 
-    // Log events to stdout.
     if let Some(level) = opts.tracing_level() {
-        // Writing to stderr so if we have output like JSON then we can pipe it to something else.
-        let subscriber = FmtSubscriber::builder()
-            .with_max_level(level)
-            .with_writer(std::io::stderr)
-            .finish();
-
-        tracing::subscriber::set_global_default(subscriber)
-            .expect("setting default subscriber failed");
+        create_log(level, opts.log_dir.as_ref()).expect("cannot create logging");
     }
 
     if let Err(e) = cmd::exec(&opts).await {
@@ -30,6 +31,88 @@ async fn main() {
     }
 }
 
+fn create_log(level: tracing::Level, log_dir: Option<&PathBuf>) -> anyhow::Result<()> {
+    let console_appender = config::Appender::Console;
+
+    // default logging output info log to console
+    let default = config::Logger {
+        level: config::LevelFilter::from_str(level.as_str())?,
+        appenders: literally::hset! { AppenderId::from("console") },
+        format: Format::default(),
+    };
+
+    let mut config = Config {
+        default,
+        loggers: literally::hmap! {},
+        appenders: literally::hmap! {AppenderId::from("console") => console_appender},
+    };
+
+    if let Some(log_dir) = log_dir {
+        let log_folder = expand_tilde(log_dir)
+            .to_str()
+            .ok_or_else(|| anyhow!("cannot parse log folder"))?
+            .to_string();
+        std::fs::create_dir_all(&log_folder).context("cannot create log folder")?;
+
+        let topdown_appender = config::Appender::RollingFile {
+            path: format!("{log_folder}/topdown.log"),
+            policy: Policy {
+                maximum_file_size: "10mb".to_string(),
+                // we keep the last 5 log files, older files will be deleted
+                max_size_roll_backups: 5,
+                pattern: None,
+            },
+        };
+        let debug_appender = config::Appender::RollingFile {
+            path: format!("{log_folder}/debug.log"),
+            policy: Policy {
+                maximum_file_size: "10mb".to_string(),
+                // we keep the last 5 log files, older files will be deleted
+                max_size_roll_backups: 5,
+                pattern: None,
+            },
+        };
+
+        let topdown_logger = config::Logger {
+            level: config::LevelFilter::DEBUG,
+            appenders: literally::hset! { AppenderId::from("topdown") },
+            format: Format::default(),
+        };
+        let debug_logger = config::Logger {
+            level: config::LevelFilter::DEBUG,
+            appenders: literally::hset! { AppenderId::from("debug") },
+            format: Format::default(),
+        };
+
+        config.loggers.insert(
+            Target::from("fendermint_vm_topdown"),
+            topdown_logger.clone(),
+        );
+        config.loggers.insert(
+            Target::from("fendermint_vm_interpreter::chain"),
+            topdown_logger,
+        );
+        config
+            .appenders
+            .insert(AppenderId::from("topdown"), topdown_appender);
+
+        config
+            .loggers
+            // "" matches everything
+            .insert(Target::from(""), debug_logger);
+        config
+            .appenders
+            .insert(AppenderId::from("debug"), debug_appender);
+    }
+
+    let handle = Arc::new(Handle::try_from(config).unwrap());
+
+    tracing::subscriber::set_global_default(handle.subscriber())
+        .context("setting default subscriber failed")?;
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use cid::Cid;