Refactor Telemetry Initialization and Environment Utilities (#811)

* improve code for metrics

* improve code for metrics

* fix

* fix

* Refactor telemetry initialization and environment functions ordering

- Reorder functions in envs.rs by type size (8-bit to 64-bit, signed before unsigned) and add missing variants like get_env_opt_u16.
- Optimize init_telemetry to support three modes: stdout logging (default error level with span tracing), file rolling logs (size-based with retention), and HTTP-based observability with sub-endpoints (trace, metric, log) falling back to unified endpoint.
- Fix stdout logging issue by retaining WorkerGuard in OtelGuard to prevent premature release of async writer threads.
- Enhance observability mode with HTTP protocol, compression, and proper resource management.
- Update OtelGuard to include tracing_guard for stdout and flexi_logger_handles for file logging.
- Improve error handling and configuration extraction in OtelConfig.

* fix

* up

* fix

* fix

* improve code for obs

* fix

* fix

crates/utils/src/sys/envs.rs

@@ -1,42 +0,0 @@
-//  Copyright 2024 RustFS Team
-//
-//  Licensed under the Apache License, Version 2.0 (the "License");
-//  you may not use this file except in compliance with the License.
-//  You may obtain a copy of the License at
-//
-//      http://www.apache.org/licenses/LICENSE-2.0
-//
-//  Unless required by applicable law or agreed to in writing, software
-//  distributed under the License is distributed on an "AS IS" BASIS,
-//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-//  See the License for the specific language governing permissions and
-//  limitations under the License.
-
-use std::env;
-
-pub fn get_env_usize(key: &str, default: usize) -> usize {
-    env::var(key).ok().and_then(|v| v.parse().ok()).unwrap_or(default)
-}
-pub fn get_env_u64(key: &str, default: u64) -> u64 {
-    env::var(key).ok().and_then(|v| v.parse().ok()).unwrap_or(default)
-}
-pub fn get_env_u32(key: &str, default: u32) -> u32 {
-    env::var(key).ok().and_then(|v| v.parse().ok()).unwrap_or(default)
-}
-pub fn get_env_str(key: &str, default: &str) -> String {
-    env::var(key).unwrap_or_else(|_| default.to_string())
-}
-pub fn get_env_opt_u64(key: &str) -> Option<u64> {
-    env::var(key).ok().and_then(|v| v.parse().ok())
-}
-
-pub fn get_env_bool(key: &str, default: bool) -> bool {
-    env::var(key)
-        .ok()
-        .and_then(|v| match v.to_lowercase().as_str() {
-            "1" | "true" | "yes" => Some(true),
-            "0" | "false" | "no" => Some(false),
-            _ => None,
-        })
-        .unwrap_or(default)
-}

crates/utils/src/sys/mod.rs

@@ -12,5 +12,4 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-pub(crate) mod envs;
 pub(crate) mod user_agent;