probe-rs · Yatekii · Dec 10, 2023 · Dec 10, 2023 · Dec 10, 2023 · Dec 10, 2023
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/changelog/changed-log-to-file-opt-in.md b/changelog/changed-log-to-file-opt-in.md
@@ -0,0 +1 @@
+Logging to file is now off by default. Use `--log-to-folder` or `--log-file` to enable.
diff --git a/probe-rs/Cargo.toml b/probe-rs/Cargo.toml
@@ -58,6 +58,7 @@ cli = [
     "dep:terminal_size",
     "dep:termtree",
     "dep:time",
+    "dep:tracing-appender",
     "dep:tracing-subscriber",
     "dep:git-version",
     "dep:serde_json",
@@ -184,6 +185,7 @@ tracing-subscriber = { version = "0.3.18", features = [
     "env-filter",
     "json",
 ], optional = true }
+tracing-appender = { version = "0.2.3", optional = true }
 ratatui = { version = "0.24.0", default-features = false, features = [
     "crossterm",
 ], optional = true }

diff --git a/probe-rs/src/architecture/riscv/mod.rs b/probe-rs/src/architecture/riscv/mod.rs
@@ -237,10 +237,15 @@ impl<'probe> CoreInterface for Riscv32<'probe> {
         // write 1 to the haltreq register, which is part
         // of the dmcontrol register
 
-        tracing::debug!(
-            "Before requesting halt, the Dmcontrol register value was: {:?}",
-            self.interface.read_dm_register::<Dmcontrol>()?
-        );
+        if tracing::enabled!(tracing::Level::DEBUG) {
+            // For some reason inlining this read into the log macro causes it to be printed
+            // even if debug prints are disabled.
+            let dmc = self.interface.read_dm_register::<Dmcontrol>()?;
+            tracing::debug!(
+                "Before requesting halt, the Dmcontrol register value was: {:?}",
+                dmc
+            );
+        }
 
         let mut dmcontrol = Dmcontrol(0);
 

diff --git a/probe-rs/src/bin/probe-rs/main.rs b/probe-rs/src/bin/probe-rs/main.rs
@@ -40,9 +40,12 @@ const MAX_LOG_FILES: usize = 20;
 struct Cli {
     /// Location for log file
     ///
-    /// If no location is specified, the log file will be stored in a default directory.
+    /// If no location is specified, the behaviour depends on `--log-to-folder`.
     #[clap(long, global = true)]
     log_file: Option<PathBuf>,
+    /// Enable logging to the default folder. This option is ignored if `--log-file` is specified.
+    #[clap(long, global = true)]
+    log_to_folder: bool,
     #[clap(subcommand)]
     subcommand: Subcommand,
 }
@@ -269,27 +272,20 @@ fn main() -> Result<()> {
     }
 
     let log_path = if let Some(location) = matches.log_file {
-        location
-    } else {
+        Some(location)
+    } else if matches.log_to_folder {
         let location =
             default_logfile_location().context("Unable to determine default log file location.")?;
         prune_logs(
             location
                 .parent()
                 .expect("A file parent directory. Please report this as a bug."),
         )?;
-        location
+        Some(location)
+    } else {
+        None
     };
 
-    let log_file = File::create(&log_path)?;
-
-    let file_subscriber = tracing_subscriber::fmt::layer()
-        .json()
-        .with_file(true)
-        .with_line_number(true)
-        .with_span_events(FmtSpan::FULL)
-        .with_writer(log_file);
-
     let stdout_subscriber = tracing_subscriber::fmt::layer()
         .compact()
         .without_time()
@@ -299,12 +295,38 @@ fn main() -> Result<()> {
                 .from_env_lossy(),
         );
 
-    tracing_subscriber::registry()
-        .with(stdout_subscriber)
-        .with(file_subscriber)
-        .init();
+    let _append_guard = if let Some(ref log_path) = log_path {
+        let log_file = File::create(log_path)?;
+
+        let (file_appender, guard) = tracing_appender::non_blocking::NonBlockingBuilder::default()
+            .lossy(false)
+            .buffered_lines_limit(128 * 1024)
+            .finish(log_file);
+
+        let file_subscriber = tracing_subscriber::fmt::layer()
+            .json()
+            .with_file(true)
+            .with_line_number(true)
+            .with_span_events(FmtSpan::FULL)
+            .with_writer(file_appender);
 
-    tracing::info!("Writing log to {:?}", log_path);
+        tracing_subscriber::registry()
+            .with(stdout_subscriber)
+            .with(file_subscriber)
+            .init();
+
+        Some(guard)
+    } else {
+        tracing_subscriber::registry()
+            .with(stdout_subscriber)
+            .init();
+
+        None
+    };
+
+    if let Some(ref log_path) = log_path {
+        tracing::info!("Writing log to {:?}", log_path);
+    }
 
     let result = match matches.subcommand {
         Subcommand::DapServer { .. } => unreachable!(), // handled above.
@@ -326,7 +348,9 @@ fn main() -> Result<()> {
         Subcommand::Write(cmd) => cmd.run(&lister),
     };
 
-    tracing::info!("Wrote log to {:?}", log_path);
+    if let Some(ref log_path) = log_path {
+        tracing::info!("Wrote log to {:?}", log_path);
+    }
 
     result
 }
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Logging to file is now off by default. Use `--log-to-folder` or `--log-file` to enable.