fix: disable tracing file log by default

README.md

@@ -182,10 +182,10 @@ To renew the SSL certificate, you can run the same command as above:
 The gateway uses the [tracing](https://docs.rs/tracing) crate for logging. There are two tracing outputs configured:
 
 -   output to **stdout**, which has the `info` level and can be configured with the `RUST_LOG_STDOUT` env variable, see below;
--   output to a **file**, which is saved in the `data/traces/` folder and has the default `trace` level. The file name is `gateway_{start-timestamp}.log`. It can be configured with the `RUST_LOG_FILE` env variable, see below.
+-   output to a **file**, which is saved in the `data/traces/` folder and is disabled by default. The file name is `gateway_{start-timestamp}.log`. It can be configured with the `RUST_LOG_FILE` env variable, see below.
 
-The `RUST_LOG` environment variable enables to set different levels for each module. See the [EnvFilter](https://docs.rs/tracing-subscriber/0.3.17/tracing_subscriber/filter/struct.EnvFilter.html) documentation for more details.
-For example, to set the tracing level to `debug`, you can run:
+The `RUST_LOG_*` environment variable enables to set different levels for each module. See the [EnvFilter](https://docs.rs/tracing-subscriber/0.3.17/tracing_subscriber/filter/struct.EnvFilter.html) documentation for more details.
+For example, to set the tracing level to `debug` for both `stdout` and `file`, you can run:
 
 ```
 RUST_LOG_FILE=ic_websocket_gateway=debug RUST_LOG_STDOUT=ic_websocket_gateway=debug cargo run

src/ic-websocket-gateway/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ic_websocket_gateway"
-version = "1.4.5"
+version = "1.4.6"
 edition.workspace = true
 rust-version.workspace = true
 repository.workspace = true
@@ -24,11 +24,11 @@ futures-util = "0.3"
 structopt = "0.3"
 tracing = { workspace = true }
 tracing-subscriber = { version = "0.3", features = [
-  "fmt",
-  "std",
-  "json",
-  "env-filter",
-  "registry",
+    "fmt",
+    "std",
+    "json",
+    "env-filter",
+    "registry",
 ] }
 tracing-appender = "0.2"
 tracing-opentelemetry = "0.22"

src/ic-websocket-gateway/src/gateway_tracing.rs

@@ -7,6 +7,7 @@ use std::{
     path::Path,
     time::{SystemTime, UNIX_EPOCH},
 };
+use tracing::level_filters::LevelFilter;
 use tracing_appender::non_blocking::WorkerGuard;
 use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::{prelude::*, EnvFilter};
@@ -20,40 +21,57 @@ pub fn init_tracing(
     opentelemetry_collector_endpoint: Option<String>,
     gateway_principal: Principal,
 ) -> Result<InitTracingResult, String> {
-    if !Path::new("./data/traces").is_dir() {
-        fs::create_dir("./data/traces").map_err(|e| e.to_string())?;
-    }
-
-    let timestamp = SystemTime::now()
-        .duration_since(UNIX_EPOCH)
-        .map_err(|e| e.to_string())?;
-    let filename = format!("./data/traces/gateway_{:?}.log", timestamp.as_millis());
-
-    println!("Tracing to file: {}", filename);
-
-    let log_file = File::create(filename).map_err(|e| e.to_string())?;
-    let (non_blocking_file, guard_file) = tracing_appender::non_blocking(log_file);
-    let (non_blocking_stdout, guard_stdout) = tracing_appender::non_blocking(std::io::stdout());
-
-    let env_filter_file = EnvFilter::builder()
-        .with_env_var("RUST_LOG_FILE")
-        .try_from_env()
-        .unwrap_or_else(|_| EnvFilter::new("ic_websocket_gateway=trace"));
-
-    let file_tracing_layer = tracing_subscriber::fmt::layer()
-        .json()
-        .with_writer(non_blocking_file)
-        .with_thread_ids(true)
-        .with_filter(env_filter_file);
-
-    let env_filter_stdout = EnvFilter::builder()
-        .with_env_var("RUST_LOG_STDOUT")
-        .try_from_env()
-        .unwrap_or_else(|_| EnvFilter::new("ic_websocket_gateway=info"));
-    let stdout_tracing_layer = tracing_subscriber::fmt::layer()
-        .with_writer(non_blocking_stdout)
-        .pretty()
-        .with_filter(env_filter_stdout);
+    // stdout tracing
+    let (stdout_tracing_layer, guard_stdout) = {
+        let (non_blocking_stdout, guard_stdout) = tracing_appender::non_blocking(std::io::stdout());
+
+        let env_filter_stdout = EnvFilter::builder()
+            .with_env_var("RUST_LOG_STDOUT")
+            .try_from_env()
+            .unwrap_or_else(|_| EnvFilter::new("ic_websocket_gateway=info"));
+        let stdout_tracing_layer = tracing_subscriber::fmt::layer()
+            .with_writer(non_blocking_stdout)
+            .pretty()
+            .with_filter(env_filter_stdout);
+
+        (stdout_tracing_layer, guard_stdout)
+    };
+
+    // file tracing
+    let (file_tracing_layer, guard_file) = {
+        if !Path::new("./data/traces").is_dir() {
+            fs::create_dir("./data/traces").map_err(|e| e.to_string())?;
+        }
+
+        let timestamp = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .map_err(|e| e.to_string())?;
+        let filename = format!("./data/traces/gateway_{:?}.log", timestamp.as_millis());
+
+        println!("Tracing to file: {}", filename);
+
+        let log_file = File::create(filename).map_err(|e| e.to_string())?;
+        let (non_blocking_file, guard_file) = tracing_appender::non_blocking(log_file);
+
+        let env_filter_file = EnvFilter::builder()
+            .with_env_var("RUST_LOG_FILE")
+            .try_from_env()
+            .unwrap_or_else(|_| {
+                // disable file tracing by default
+                EnvFilter::builder()
+                    .with_default_directive(LevelFilter::OFF.into())
+                    .parse("")
+                    .expect("failed to parse default filter for file tracing")
+            });
+
+        let file_tracing_layer = tracing_subscriber::fmt::layer()
+            .json()
+            .with_writer(non_blocking_file)
+            .with_thread_ids(true)
+            .with_filter(env_filter_file);
+
+        (file_tracing_layer, guard_file)
+    };
 
     let is_telemetry_enabled =
         match opentelemetry_collector_endpoint