main: make log level dynamic

* set the log level via environment variable

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

advotracker/src/main.rs

@@ -29,7 +29,7 @@ use advotracker::widgets::main_view;
 
 mod parse_args;
 
-/// respect environment variables set in .env files
+/// define valid environment variables provided via .env files
 /// located in the current call directory
 /// this is primarily used in testing scenarios (eg. debugging)
 #[derive(Debug, Deserialize)]
@@ -71,15 +71,20 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     //static DEFAULT_FILTER: &str = concat!(module_path!(), "=", "trace");
 
+    // respect dotenv environment (e.g for testing)
+    // -> overwrites the preset default values
+    let log = dotenv::var("RUST_LOG").unwrap_or_else(|_| String::from("None"));
+
     // initialize the tracing subsystem
     // a drop in replacement for classical logging
     // reference: https://tokio.rs/blog/2019-08-tracing/
-    let span = tracing::span!(Level::TRACE, "csv-test");
+
+    let span = tracing::span!(Level::TRACE, "advotracker");
     let _enter = span.enter();
     let subscriber = fmt::Subscriber::builder()
-        .with_env_filter("trace")
-        //.with_max_level(tracing::Level::DEBUG)
-        .finish();
+	.with_env_filter(&log)
+	//.with_max_level(tracing::Level::DEBUG)
+	.finish();
 
     tracing::subscriber::with_default(subscriber, || {
         // get system environment