Add logging

Author: ddoktorski

Cargo.lock

@@ -6,4 +6,6 @@ edition = "2024"
 [dependencies]
 dap = { git = "https://github.com/software-mansion-labs/dap-rs", rev = "4440a6f" }
 tracing = "0.1"
+tracing-chrome = "0.7"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 anyhow = "1.0"

Cargo.toml

@@ -4,6 +4,7 @@ use crate::connection::Connection;
 use crate::debugger::handler::{HandleResult, NextAction};
 
 mod handler;
+mod log;
 
 pub struct CairoDebugger {
     connection: Connection,
@@ -36,4 +37,8 @@ impl CairoDebugger {
 
         Ok(())
     }
+
+    pub fn init_logging() -> Option<impl Drop> {
+        log::init_logging()
+    }
 }

src/debugger.rs

@@ -0,0 +1,71 @@
+use std::io::IsTerminal;
+use std::path::PathBuf;
+use std::time::SystemTime;
+use std::{env, fs, io};
+
+use tracing_chrome::ChromeLayerBuilder;
+use tracing_subscriber::filter::{EnvFilter, LevelFilter, Targets};
+use tracing_subscriber::fmt::Layer;
+use tracing_subscriber::fmt::time::Uptime;
+use tracing_subscriber::prelude::*;
+
+pub fn init_logging() -> Option<impl Drop> {
+    let mut guard = None;
+
+    let fmt_layer = Layer::new()
+        .with_writer(io::stderr)
+        .with_ansi(io::stderr().is_terminal())
+        .with_timer(Uptime::default())
+        .with_filter(
+            EnvFilter::builder()
+                .with_default_directive(LevelFilter::WARN.into())
+                .with_env_var("CAIRO_DEBUGGER_LOG")
+                .from_env_lossy(),
+        );
+
+    let tracing_profile = env::var("CAIRO_DEBUGGER_TRACING_PROFILE").ok().is_some_and(|var| {
+        let s = var.as_str();
+        s == "true" || s == "1"
+    });
+
+    let profile_layer = if tracing_profile {
+        let mut path = PathBuf::from(format!(
+            "./cairo-debugger-profile-{}.json",
+            SystemTime::UNIX_EPOCH.elapsed().unwrap().as_micros()
+        ));
+
+        // Create the file now, so that we early panic, and `fs::canonicalize` will work.
+        let profile_file = fs::File::create(&path).expect("failed to create profile file");
+
+        // Try to canonicalize the path so that it is easier to find the file from logs.
+        if let Ok(canonical) = fs::canonicalize(&path) {
+            path = canonical;
+        }
+
+        eprintln!("Cairo Debugger run will output tracing profile to: {}", path.display());
+        eprintln!(
+            "Open that file with https://ui.perfetto.dev (or chrome://tracing) to analyze it"
+        );
+
+        let (profile_layer, profile_layer_guard) =
+            ChromeLayerBuilder::new().writer(profile_file).include_args(true).build();
+
+        // Filter out less important logs because they're too verbose,
+        // and with them the profile file quickly grows to several GBs of data.
+        let profile_layer = profile_layer.with_filter(
+            Targets::new().with_default(LevelFilter::TRACE).with_target("salsa", LevelFilter::WARN),
+        );
+
+        guard = Some(profile_layer_guard);
+        Some(profile_layer)
+    } else {
+        None
+    };
+
+    tracing::subscriber::set_global_default(
+        tracing_subscriber::registry().with(fmt_layer).with(profile_layer),
+    )
+    .expect("could not set up global logger");
+
+    guard
+}