Add logging level when using logfile (#721)

lighthouse/environment/src/lib.rs

@@ -228,7 +228,7 @@ impl<E: EthSpec> Environment<E> {
     }
 
     /// Sets the logger (and all child loggers) to log to a file.
-    pub fn log_to_json_file(&mut self, path: PathBuf) -> Result<(), String> {
+    pub fn log_to_json_file(&mut self, path: PathBuf, debug_level: &str) -> Result<(), String> {
         let file = OpenOptions::new()
             .create(true)
             .write(true)
@@ -237,8 +237,19 @@ impl<E: EthSpec> Environment<E> {
             .map_err(|e| format!("Unable to open logfile: {:?}", e))?;
 
         let drain = Mutex::new(slog_json::Json::default(file)).fuse();
-        let drain = slog_async::Async::new(drain).build().fuse();
-        self.log = slog::Logger::root(drain, o!());
+        let drain = slog_async::Async::new(drain).build();
+
+        let drain = match debug_level {
+            "info" => drain.filter_level(Level::Info),
+            "debug" => drain.filter_level(Level::Debug),
+            "trace" => drain.filter_level(Level::Trace),
+            "warn" => drain.filter_level(Level::Warning),
+            "error" => drain.filter_level(Level::Error),
+            "crit" => drain.filter_level(Level::Critical),
+            unknown => return Err(format!("Unknown debug-level: {}", unknown)),
+        };
+
+        self.log = Logger::root(drain.fuse(), o!());
 
         info!(
             self.log,

lighthouse/src/main.rs

@@ -95,12 +95,12 @@ fn run<E: EthSpec>(
     environment_builder: EnvironmentBuilder<E>,
     matches: &ArgMatches,
 ) -> Result<(), String> {
+    let debug_level = matches
+        .value_of("debug-level")
+        .ok_or_else(|| "Expected --debug-level flag".to_string())?;
+
     let mut environment = environment_builder
-        .async_logger(
-            matches
-                .value_of("debug-level")
-                .ok_or_else(|| "Expected --debug-level flag".to_string())?,
-        )?
+        .async_logger(debug_level)?
         .multi_threaded_tokio_runtime()?
         .build()?;
 
@@ -110,7 +110,7 @@ fn run<E: EthSpec>(
         let path = log_path
             .parse::<PathBuf>()
             .map_err(|e| format!("Failed to parse log path: {:?}", e))?;
-        environment.log_to_json_file(path)?;
+        environment.log_to_json_file(path, debug_level)?;
     }
 
     if std::mem::size_of::<usize>() != 8 {