Detect log format metadata (#809)

* Detect log format metadata

* Match section name

* Update HIL test

* Changelog

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add `--monitor` option to `write-bin`. (#783)
 - Add `watchdog-reset` strategy to `--after` subcommand (#779)
 - Add `ROM` version of `read-flash` command (#812)
+- `espflash` can detect the log format automatically from ESP-HAL metadata. Reqires `esp-println` 0.14 (presumably, yet to be released) (#809)
 
 ### Changed
 

espflash/src/cli/mod.rs

@@ -280,8 +280,8 @@ pub struct MonitorConfigArgs {
     #[arg(long, requires = "non_interactive")]
     no_reset: bool,
     /// Logging format.
-    #[arg(long, short = 'L', default_value = "serial")]
-    log_format: LogFormat,
+    #[arg(long, short = 'L')]
+    log_format: Option<LogFormat>,
     /// External log processors to use (comma separated executables)
     #[arg(long)]
     processors: Option<String>,

espflash/src/cli/monitor/mod.rs

@@ -20,7 +20,7 @@ use crossterm::{
     terminal::{disable_raw_mode, enable_raw_mode},
 };
 use external_processors::ExternalProcessors;
-use log::{debug, error};
+use log::{debug, error, warn};
 use miette::{IntoDiagnostic, Result};
 #[cfg(feature = "serialport")]
 use serialport::SerialPort;
@@ -28,7 +28,10 @@ use strum::{Display, EnumIter, EnumString, VariantNames};
 
 use crate::{
     cli::{
-        monitor::parser::{InputParser, ResolvingPrinter},
+        monitor::{
+            parser::{InputParser, ResolvingPrinter},
+            symbols::Symbols,
+        },
         MonitorConfigArgs,
     },
     connection::{reset::reset_after_flash, Port},
@@ -102,7 +105,10 @@ pub fn monitor(
     let stdout = stdout();
     let mut stdout = ResolvingPrinter::new(elf, stdout.lock());
 
-    let mut parser: Box<dyn InputParser> = match monitor_args.log_format {
+    let mut parser: Box<dyn InputParser> = match monitor_args
+        .log_format
+        .unwrap_or_else(|| deduce_log_format(elf))
+    {
         LogFormat::Defmt => Box::new(parser::esp_defmt::EspDefmt::new(elf)?),
         LogFormat::Serial => Box::new(parser::serial::Serial),
     };
@@ -151,6 +157,34 @@ pub fn monitor(
     Ok(())
 }
 
+fn deduce_log_format(elf: Option<&[u8]>) -> LogFormat {
+    let Some(elf) = elf else {
+        return LogFormat::Serial;
+    };
+
+    let Ok(symbols) = Symbols::try_from(elf) else {
+        return LogFormat::Serial;
+    };
+
+    let Some(format_symbol) =
+        symbols.get_symbol_data(Some(".espressif.metadata"), b"espflash.LOG_FORMAT")
+    else {
+        return LogFormat::Serial;
+    };
+
+    match format_symbol {
+        b"defmt-espflash" => LogFormat::Defmt,
+        b"serial" => LogFormat::Serial,
+        other => {
+            warn!(
+                "Unknown log format symbol: {}. Defaulting to serial.",
+                String::from_utf8_lossy(other),
+            );
+            LogFormat::Serial
+        }
+    }
+}
+
 // Converts key events from crossterm into appropriate character/escape
 // sequences which are then sent over the serial connection.
 //

espflash/src/cli/monitor/symbols.rs

@@ -98,4 +98,18 @@ impl<'sym> Symbols<'sym> {
             }
         })?
     }
+
+    pub(crate) fn get_symbol_data(
+        &self,
+        section_name: Option<&str>,
+        name_bytes: &[u8],
+    ) -> Option<&'sym [u8]> {
+        let sym = self.object.symbol_by_name_bytes(name_bytes)?;
+
+        let section = match section_name {
+            Some(section_name) => self.object.section_by_name(section_name)?,
+            None => self.object.section_by_index(sym.section_index()?).ok()?,
+        };
+        section.data_range(sym.address(), sym.size()).ok().flatten()
+    }
 }

espflash/tests/data/README.md

@@ -8,6 +8,8 @@ cargo build --release
 
 The `esp32c6_defmt` elf file under this folder has been generated using `esp-generate@04d69c9`:
 
+> TODO: this part needs to be updated, and the elf re-created once ESP-HAL beta.1 is out.
+
 ```
 esp-generate --chip=esp32c6 -o defmt --headless esp32c6_defmt
 cd esp32c6_defmt

espflash/tests/scripts/flash.sh

@@ -2,6 +2,7 @@
 app="espflash/tests/data/$1"
 
 if [[ "$1" == "esp32c6" ]]; then
+    # With manual log-format
     app_defmt="${app}_defmt"
     result=$(timeout 8s espflash flash --no-skip --monitor --non-interactive $app_defmt --log-format defmt 2>&1)
     echo "$result"
@@ -13,6 +14,18 @@ if [[ "$1" == "esp32c6" ]]; then
         echo "Monitoring failed!"
         exit 1
     fi
+
+    # With auto-detected log-format
+    result=$(timeout 8s espflash flash --no-skip --monitor --non-interactive $app_defmt 2>&1)
+    echo "$result"
+    if [[ ! $result =~ "Flashing has completed!" ]]; then
+        echo "Flashing failed!"
+        exit 1
+    fi
+    if ! echo "$result" | grep -q "Hello world!"; then
+        echo "Monitoring failed!"
+        exit 1
+    fi
 fi
 
 result=$(timeout 8s espflash flash --no-skip --monitor --non-interactive $app 2>&1)