Support setting config file path via system env and improve error handling in SentinelConfigLoader

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/config/SentinelConfigLoader.java

@@ -35,7 +35,8 @@ import static com.alibaba.csp.sentinel.util.ConfigUtil.addSeparator;
  */
 public final class SentinelConfigLoader {
 
-    public static final String SENTINEL_CONFIG = "csp.sentinel.config.file";
+    public static final String SENTINEL_CONFIG_ENV_KEY = "CSP_SENTINEL_CONFIG_FILE";
+    public static final String SENTINEL_CONFIG_PROPERTY_KEY = "csp.sentinel.config.file";
 
     private static final String DIR_NAME = "logs" + File.separator + "csp";
     private static final String USER_HOME = "user.home";
@@ -45,13 +46,21 @@ public final class SentinelConfigLoader {
     private static Properties properties = new Properties();
 
     static {
-        load();
+        try {
+            load();
+        } catch (Throwable t) {
+            RecordLog.warn("[SentinelConfigLoader] Failed to initialize configuration items", t);
+        }
     }
 
     private static void load() {
-        String fileName = System.getProperty(SENTINEL_CONFIG);
+        // Order: system property -> system env -> default file (classpath:sentinel.properties) -> legacy path
+        String fileName = System.getProperty(SENTINEL_CONFIG_PROPERTY_KEY);
         if (StringUtil.isBlank(fileName)) {
-            fileName = DEFAULT_SENTINEL_CONFIG_FILE;
+            fileName = System.getenv(SENTINEL_CONFIG_ENV_KEY);
+            if (StringUtil.isBlank(fileName)) {
+                fileName = DEFAULT_SENTINEL_CONFIG_FILE;
+            }
         }
 
         Properties p = ConfigUtil.loadProperties(fileName);
@@ -88,5 +97,4 @@ public final class SentinelConfigLoader {
         return properties;
     }
 
-
 }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/log/LogConfigLoader.java

@@ -30,23 +30,34 @@ import java.util.concurrent.CopyOnWriteArraySet;
  */
 public class LogConfigLoader {
 
-    public static final String LOG_CONFIG = "csp.sentinel.config.file";
+    public static final String LOG_CONFIG_ENV_KEY = "CSP_SENTINEL_CONFIG_FILE";
+    public static final String LOG_CONFIG_PROPERTY_KEY = "csp.sentinel.config.file";
 
     private static final String DEFAULT_LOG_CONFIG_FILE = "classpath:sentinel.properties";
 
     private static final Properties properties = new Properties();
 
     static {
-        load();
+        try {
+            load();
+        } catch (Throwable t) {
+            // NOTE: do not use RecordLog here, or there will be circular class dependency!
+            System.err.println("[LogConfigLoader] Failed to initialize configuration items");
+            t.printStackTrace();
+        }
     }
 
     private static void load() {
-        String file = System.getProperty(LOG_CONFIG);
-        if (StringUtil.isBlank(file)) {
-            file = DEFAULT_LOG_CONFIG_FILE;
+        // Order: system property -> system env -> default file (classpath:sentinel.properties) -> legacy path
+        String fileName = System.getProperty(LOG_CONFIG_PROPERTY_KEY);
+        if (StringUtil.isBlank(fileName)) {
+            fileName = System.getenv(LOG_CONFIG_ENV_KEY);
+            if (StringUtil.isBlank(fileName)) {
+                fileName = DEFAULT_LOG_CONFIG_FILE;
+            }
         }
 
-        Properties p = ConfigUtil.loadProperties(file);
+        Properties p = ConfigUtil.loadProperties(fileName);
         if (p != null && !p.isEmpty()) {
             properties.putAll(p);
         }