refactor: improve logging

src/identifier.rs

@@ -15,11 +15,16 @@
 use crate::plugin::Plugin;
 use std::path::Path;
 
+#[tracing::instrument(skip(input, plugins))]
 pub fn identify_format(path: &str, input: &[u8], plugins: &[Box<dyn Plugin>]) -> Option<&'static str> {
+    tracing::trace!("Identifying format for path: {}", path);
     let mut ext_str_opt = None;
 
     if let Some(kind) = infer::get(input) {
+        tracing::trace!("infer detected file type: {:?}", kind.mime_type());
         ext_str_opt = Some(kind.extension());
+    } else if !input.is_empty() {
+        tracing::trace!("infer failed to detect file type from magic bytes.");
     }
 
     let p = Path::new(path);
@@ -33,23 +38,31 @@ pub fn identify_format(path: &str, input: &[u8], plugins: &[Box<dyn Plugin>]) ->
     }
 
     let mut ext_str = ext.as_deref().unwrap_or("");
-    if ext_str_opt.is_some() {
-        ext_str = ext_str_opt.unwrap();
+    if let Some(magic_ext) = ext_str_opt {
+        tracing::debug!("Using magic byte extension over path extension: {} -> {}", ext_str, magic_ext);
+        ext_str = magic_ext;
+    } else {
+        tracing::debug!("Using path extension: {}", ext_str);
     }
 
     let ext_str = match ext_str {
         "jpg" => "jpeg",
         other => other,
     };
+    tracing::trace!("Normalized extension to check plugins against: {}", ext_str);
 
     for plugin in plugins {
+        tracing::trace!("Checking plugin {} formats for support of {}", plugin.name(), ext_str);
         if let Some(&f) = plugin.from_formats().iter().find(|&&f| f == ext_str) {
+            tracing::debug!("Plugin {} supports {} as input.", plugin.name(), f);
             return Some(f);
         }
         if let Some(&f) = plugin.to_formats().iter().find(|&&f| f == ext_str) {
+            tracing::debug!("Plugin {} supports {} as output.", plugin.name(), f);
             return Some(f);
         }
     }
+    tracing::debug!("No plugin supports the format '{}'.", ext_str);
     None
 }