Keep both stderr and file writers

ipa-core/src/cli/verbosity.rs

@@ -45,29 +45,32 @@ impl Verbosity {
         let filter_layer = self.log_filter();
         info!("Logging setup at level {}", filter_layer);
 
-        let registry = tracing_subscriber::registry().with(filter_layer);
+        let stderr_writer = fmt::layer()
+            .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
+            .with_ansi(std::io::stderr().is_terminal())
+            .with_writer(stderr);
+
+        let registry = tracing_subscriber::registry()
+            .with(filter_layer)
+            .with(stderr_writer);
 
         if let Some(path) = &self.log_file {
             let log_file = OpenOptions::new()
                 .append(true)
                 .create(true)
                 .open(path)
                 .unwrap_or_else(|e| panic!("failed to open log file {path:?}: {e}"));
-            let fmt_layer = fmt::layer()
+            let file_writer = fmt::layer()
                 .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
                 .with_ansi(false)
                 .with_writer(log_file);
 
             // that's the only stderr message that should appear to give a hint where
             // the logs are written to
-            eprintln!("Logs will be written to {path:?}");
-            registry.with(fmt_layer).init();
+            tracing::info!("Logs will be written to {path:?}");
+            registry.with(file_writer).init();
         } else {
-            let fmt_layer = fmt::layer()
-                .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
-                .with_ansi(std::io::stderr().is_terminal())
-                .with_writer(stderr);
-            registry.with(fmt_layer).init();
+            registry.init();
         }
 
         let metrics_handle = install_collector().expect("Can install metrics");