feat: support configuring the EnvFilter for tracing

src/main.rs

@@ -4,7 +4,7 @@ use opendal::{IntoOperatorUri, Operator, OperatorUri};
 use secrecy::{ExposeSecret, SecretString};
 use snafu::Snafu;
 use std::{fmt::Debug, str::FromStr};
-use tracing_subscriber::fmt::format::FmtSpan;
+use tracing_subscriber::{EnvFilter, fmt::format::FmtSpan};
 use twilight_gateway::{Event, EventTypeFlags, Intents, Shard, ShardId, StreamExt};
 use twilight_model::id::{Id, marker::UserMarker};
 
@@ -44,7 +44,7 @@ impl Debug for OpendalOperator {
 }
 
 #[derive(Debug, Parser)]
-struct Args {
+struct AppArgs {
     #[arg(long, env)]
     discord_token: SecretString,
 
@@ -55,26 +55,47 @@ struct Args {
     bot_owner: Id<UserMarker>,
 }
 
+#[derive(Parser)]
+struct LoggingArgs {
+    #[arg(long = "logging-directives", env = "RUST_LOG", default_value = "info")]
+    env_filter: EnvFilter,
+}
+
+#[derive(Parser)]
+struct Args {
+    #[clap(flatten)]
+    app_args: AppArgs,
+
+    #[clap(flatten)]
+    logging_args: LoggingArgs,
+}
+
 #[derive(Debug, Snafu)]
 enum MainError {}
 
 #[snafu::report]
 #[tokio::main]
 async fn main() -> Result<(), MainError> {
+    let Args {
+        logging_args,
+        app_args,
+    } = Parser::parse();
+
+    let LoggingArgs { env_filter } = logging_args;
+
     tracing_subscriber::fmt()
         .pretty()
+        .with_env_filter(env_filter)
         .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
         .init();
 
-    let args = Parser::parse();
+    tracing::debug!(?app_args, "using");
 
-    tracing::debug!(?args, "using");
-
-    let Args {
+    let AppArgs {
         discord_token,
         storage,
         bot_owner,
-    } = args;
+    } = app_args;
 
     rustls::crypto::aws_lc_rs::default_provider()
         .install_default()