Tracing and configurable log level

Author: Brian Pfretzschner

cli/Cargo.toml

@@ -12,6 +12,7 @@ rt = { path = "../rt" }
 
 clap = { version = "3.1.2", features = ["derive"] }
 prettytable-rs = "0.10"
-env_logger = "0.11"
 anyhow = { version = "1.0", features = ["backtrace"] }
 better-panic = "0.3.0"
+tracing = "0.1.41"
+tracing-subscriber = { version = "0.3.19", features = ["env-filter"] }

cli/src/execute.rs

@@ -2,13 +2,20 @@ use std::path::PathBuf;
 
 use loader::CompositeLoader;
 use model::vm::VmThread;
+use tracing::Level;
 use vm::vm_thread::VmTheadImpl;
 use rt::bootstrap_vm;
 
 const MAIN_METHOD_NAME: &str = "main";
 const MAIN_METHOD_SIGNATURE: &str = "([Ljava/lang/String;)V";
 
-pub fn run(main_class: String, class_paths: Vec<PathBuf>) {
+pub fn run(
+    main_class: String,
+    class_paths: Vec<PathBuf>,
+    vm_init_log_level: Level,
+    vm_exec_log_level: Level,
+    set_log_level_fn: impl Fn(Level),
+) {
     let parser = parser::ClassfileParser {};
 
     let classloader = loader::classloader_for_paths(class_paths, &parser).unwrap();
@@ -17,7 +24,10 @@ pub fn run(main_class: String, class_paths: Vec<PathBuf>) {
     let classloader =
         CompositeLoader::open(vec![Box::new(runtime_classloader), Box::new(classloader)]);
 
+    set_log_level_fn(vm_init_log_level);
     let vm = bootstrap_vm(classloader);
+
+    set_log_level_fn(vm_exec_log_level);
     VmThread::new(&vm, "Thread-0".to_string()).invoke_method(
         &main_class,
         &MAIN_METHOD_NAME.to_string(),

cli/src/main.rs

@@ -2,6 +2,8 @@
 extern crate prettytable;
 
 use clap::{Parser, Subcommand};
+use tracing::{level_filters::LevelFilter, Level};
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
 use std::path::PathBuf;
 
 mod execute;
@@ -23,6 +25,12 @@ enum Command {
 
     #[clap(arg_required_else_help = true)]
     Execute {
+        #[clap(long, required = false, default_value = "ERROR")]
+        vm_init_log_level: Level,
+
+        #[clap(long, required = false, default_value = "INFO")]
+        vm_exec_log_level: Level,
+
         #[clap(required = true)]
         main_class: String,
 
@@ -32,16 +40,31 @@ enum Command {
 }
 
 fn main() {
-    env_logger::init();
+    let set_log_level_fn = tracing_init();
     better_panic::install();
 
     let args = Args::parse();
-
     match args.command {
         Command::ListClasses { class_paths } => list_classes::run(class_paths),
         Command::Execute {
             main_class,
             class_paths,
-        } => execute::run(main_class, class_paths),
+            vm_init_log_level,
+            vm_exec_log_level,
+        } => execute::run(main_class, class_paths, vm_init_log_level, vm_exec_log_level, set_log_level_fn),
     };
 }
+
+fn tracing_init() -> impl Fn(Level) {
+    let inital_log_level_filter = LevelFilter::INFO;
+    let (filter, reload_handle) = tracing_subscriber::reload::Layer::new(inital_log_level_filter);
+
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::fmt::layer().with_ansi(true))
+        .with(filter)
+        .init();
+
+    move |level: Level| reload_handle.modify(|layer| {
+        *layer = LevelFilter::from_level(level);
+    }).unwrap()
+}

loader/Cargo.toml

@@ -11,5 +11,6 @@ glob = "0.3.1"
 zip = { version = "2.1", default-features = false, features = ["deflate"] }
 anyhow = "1.0"
 log = "0.4.17"
+tracing = "0.1.41"
 
 [dev-dependencies]

model/Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 enumset = "1.1"
 anyhow = "1.0"
 itertools = "0.13"
+tracing = "0.1.41"

out.txt

@@ -9,3 +9,4 @@ model = { path = "../model" }
 enumset = "1.1"
 anyhow = "1.0"
 cesu8 = "1.1.0"
+tracing = "0.1.41"

parser/Cargo.toml

@@ -5,6 +5,8 @@ use model::class::ClassVersion;
 
 use crate::util;
 
+const SUPPORTED_MAJOR_VERSION: u16 = 55; // Corresponds to Java 11
+
 pub fn parse<T: Read>(reader: &mut T) -> Result<ClassVersion> {
     let mut magic = [0u8; 4];
     reader.read_exact(&mut magic)?;
@@ -16,8 +18,8 @@ pub fn parse<T: Read>(reader: &mut T) -> Result<ClassVersion> {
     let minor = util::read_u16(reader)?;
     let major = util::read_u16(reader)?;
 
-    if major > 55 {
-        panic!("Unsupported Classfile version: {}.{} > 51.0.", major, minor);
+    if major > SUPPORTED_MAJOR_VERSION {
+        panic!("Unsupported Classfile version: {}.{} > {}.0.", major, minor, SUPPORTED_MAJOR_VERSION);
     }
 
     Ok(ClassVersion { major, minor })

parser/src/version.rs

@@ -11,11 +11,12 @@ vm = { path = "../vm" }
 log = "0.4.17"
 anyhow = "1.0"
 dirs = "5.0"
+tracing = "0.1.41"
 
 [dev-dependencies]
 parser = { path = "../parser" }
 
 rstest = "0.22.0"
 pretty_assertions = "1.4.0"
 env_logger = "0.11"
-ctor = "0.2.8"
+ctor = "0.2.8"

rt/Cargo.toml

@@ -13,3 +13,4 @@ log = "0.4.17"
 lazy_static = "1.4.0"
 anyhow = "1.0"
 itertools = "0.13"
+tracing = "0.1.41"