fix: support underscore dashboard env vars

Author: hutiefang76

sentinel-dashboard/src/main/java/com/alibaba/csp/sentinel/dashboard/config/DashboardConfig.java

@@ -73,6 +73,13 @@ private static String getConfig(String name) {
         if (StringUtils.isNotEmpty(val)) {
             return val;
         }
+        String underscoreName = name.replace('.', '_');
+        if (!underscoreName.equals(name)) {
+            val = System.getenv(underscoreName);
+            if (StringUtils.isNotEmpty(val)) {
+                return val;
+            }
+        }
         // properties
         val = System.getProperty(name);
         if (StringUtils.isNotEmpty(val)) {

sentinel-dashboard/src/test/java/com/alibaba/csp/sentinel/dashboard/config/DashboardConfigTest.java

@@ -47,6 +47,15 @@ public void testGetConfigStr() {
         assertEquals("222", DashboardConfig.getConfigStr("a"));
     }
 
+    @Test
+    public void testGetConfigStrFromUnderscoreEnv() {
+        DashboardConfig.clearCache();
+
+        environmentVariables.set("sentinel_dashboard_auth_password", "from_env");
+
+        assertEquals("from_env", DashboardConfig.getAuthPassword());
+    }
+
     @Test
     public void testGetConfigInt() {
         // clear cache