Refactor: Add observability enable flag, improve comments, remove unused config params, and enhance run function error logging. (#689)

* improve code for dns log

* fix

* Improve comments, remove unused parameters in config.rs (opt), add observability enable flag, and enhance error logging in run function execution.

crates/obs/src/global.rs

@@ -14,6 +14,8 @@
 
 use crate::AppConfig;
 use crate::telemetry::{OtelGuard, init_telemetry};
+use opentelemetry::metrics::Meter;
+use rustfs_config::APP_NAME;
 use std::sync::{Arc, Mutex};
 use tokio::sync::{OnceCell, SetError};
 use tracing::{error, info};
@@ -21,6 +23,23 @@ use tracing::{error, info};
 /// Global guard for OpenTelemetry tracing
 static GLOBAL_GUARD: OnceCell<Arc<Mutex<OtelGuard>>> = OnceCell::const_new();
 
+/// Flag indicating if observability is enabled
+pub(crate) static IS_OBSERVABILITY_ENABLED: OnceCell<bool> = OnceCell::const_new();
+
+/// Name of the observability meter
+pub(crate) static OBSERVABILITY_METER_NAME: OnceCell<String> = OnceCell::const_new();
+
+/// Check whether Observability is enabled
+pub fn is_observability_enabled() -> bool {
+    IS_OBSERVABILITY_ENABLED.get().copied().unwrap_or(false)
+}
+
+/// Get the global meter for observability
+pub fn global_meter() -> Meter {
+    let meter_name = OBSERVABILITY_METER_NAME.get().map(|s| s.as_str()).unwrap_or(APP_NAME);
+    opentelemetry::global::meter(meter_name)
+}
+
 /// Error type for global guard operations
 #[derive(Debug, thiserror::Error)]
 pub enum GlobalError {

crates/obs/src/telemetry.rs

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 use crate::config::OtelConfig;
+use crate::global::{IS_OBSERVABILITY_ENABLED, OBSERVABILITY_METER_NAME};
 use flexi_logger::{
     Age, Cleanup, Criterion, DeferredNow, FileSpec, LogSpecification, Naming, Record, WriteMode,
     WriteMode::{AsyncWith, BufferAndFlush},
@@ -302,6 +303,8 @@ pub(crate) fn init_telemetry(config: &OtelConfig) -> OtelGuard {
                     logger_level,
                     env::var("RUST_LOG").unwrap_or_else(|_| "Not set".to_string())
                 );
+                IS_OBSERVABILITY_ENABLED.set(true).ok();
+                OBSERVABILITY_METER_NAME.set(service_name.to_string()).ok();
             }
         }