Try to execute 'dmidecode' command to get the system identifier first

.gitignore

@@ -1,3 +1,6 @@
 target/*
 vnt/src/proto/*
 common/src/generated_serial_number.rs
+
+# RustRover
+.idea

common/src/identifier.rs

@@ -52,6 +52,18 @@ pub fn get_unique_identifier() -> Option<String> {
 pub fn get_unique_identifier() -> Option<String> {
     use std::process::Command;
 
+    // Try to execute 'dmidecode' command to get the system identifier first.
+    if let Ok(output) = Command::new("dmidecode")
+        .arg("-s")
+        .arg("system-uuid")
+        .output() {
+        let identifier = String::from_utf8_lossy(&output.stdout).trim().to_owned();
+        if !identifier.is_empty() {
+            return Some(identifier.to_string());
+        }
+    }
+
+    // Try to read file /etc/machine-id if 'dmidecode' command cannot be executed or get nothing.
     // 对 linux 或 wsl 来说，读取 /etc/machine-id 即可获取当前操作系统的
     // 唯一标识，而且某些环境没有预装`dmidecode`命令
     if let Ok(identifier) = std::fs::read_to_string("/etc/machine-id") {
@@ -61,22 +73,5 @@ pub fn get_unique_identifier() -> Option<String> {
         }
     }
 
-    let output = match Command::new("dmidecode")
-        .arg("-s")
-        .arg("system-uuid")
-        .output()
-    {
-        Ok(output) => output,
-        Err(_) => {
-            return None;
-        }
-    };
-
-    let result = String::from_utf8_lossy(&output.stdout);
-    let identifier = result.trim();
-    if identifier.is_empty() {
     None
-    } else {
-        Some(identifier.to_string())
-    }
 }