feat(logging): Optimize Loki log configuration to support distributed tracing - Disable readMarkers and verbose mode to improve performance - Configure low-cardinality static labels, following official recommended practices

- Add support for structured metadata to associate trace_id and span_id
- Update the log message format to include complete exception stack trace information
- Configure HTTP timeout parameters to enhance connection stability
- Add batch processing configuration to prevent log truncation and set an appropriate buffer size
- Add downgrade handling to accommodate missing features in older API versions

cloud/plugin/plugin-micrometer/src/main/java/com/bgasol/plugin/micrometer/config/LokiAppenderConfig.java

@@ -29,32 +29,61 @@ public class LokiAppenderConfig implements ApplicationListener<ApplicationStarte
         lokiAppender.setName("LOKI");
         lokiAppender.setContext(context);
         lokiAppender.setMetricsEnabled(true);
-        lokiAppender.setReadMarkers(true);
-        lokiAppender.setStructuredMetadata("level=%level\nthread=%thread\nlogger=%logger\n*=%%mdc\n*=%%kvp");
+        lokiAppender.setReadMarkers(false);
+        lokiAppender.setVerbose(false);
+
+        // 标签：只使用低基数的静态标签（官方推荐）
         lokiAppender.setLabels(String.format(
                 "app=%s\nhost=%s",
                 serviceName,
                 context.getProperty(CoreConstants.HOSTNAME_KEY)
         ));
-        {
-            // 使用 PatternLayout 设置日志格式
-            PatternLayout layout = new PatternLayout();
-            layout.setContext(context);
-            layout.setPattern("%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} [%X{traceId:-}] - %msg%n%throwable");
-            layout.setOutputPatternAsHeader(true);
-            layout.start();
-            lokiAppender.setMessage(layout);
-        }
-        {
-            // 设置 HTTP 配置
-            PipelineConfigAppenderBase.HttpCfg httpCfg = new Loki4jAppender.HttpCfg();
-            httpCfg.setUrl(logEndpoint);
-            lokiAppender.setHttp(httpCfg);
+
+        // 结构化元数据：包含 trace_id 和 span_id，支持 Tempo 关联
+        lokiAppender.setStructuredMetadata(
+                "level=%level\n" +
+                        "thread=%thread\n" +
+                        "logger=%logger\n" +
+                        "trace_id=%mdc{traceId}\n" +
+                        "span_id=%mdc{spanId}\n" +
+                        "*=%%mdc\n" +
+                        "*=%%kvp"
+        );
+
+        // 日志消息格式：包含 traceId、spanId 和完整异常堆栈
+        PatternLayout messageLayout = new PatternLayout();
+        messageLayout.setContext(context);
+        messageLayout.setPattern(
+                "%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} " +
+                        "[traceId=%X{traceId:-}, spanId=%X{spanId:-}] - %msg%n%ex{full}"
+        );
+        messageLayout.setOutputPatternAsHeader(false);
+        messageLayout.start();
+        lokiAppender.setMessage(messageLayout);
+
+        // HTTP 配置
+        PipelineConfigAppenderBase.HttpCfg httpCfg = new Loki4jAppender.HttpCfg();
+        httpCfg.setUrl(logEndpoint);
+        httpCfg.setConnectionTimeoutMs(10000);
+        httpCfg.setRequestTimeoutMs(60000);
+        lokiAppender.setHttp(httpCfg);
+
+        // 批处理配置：防止日志被截断（关键配置）
+        try {
+            // 官方文档参数: maxItems, maxBytes, timeoutMs
+            PipelineConfigAppenderBase.BatchCfg batchCfg = new Loki4jAppender.BatchCfg();
+            batchCfg.setMaxItems(1000);
+            batchCfg.setMaxBytes(4194304); // 4MB，足够容纳完整堆栈
+            batchCfg.setTimeoutMs(1000);
+            lokiAppender.setBatch(batchCfg);
+        } catch (Exception e) {
+            // 如果 BatchCfg API 不存在，使用默认配置并记录警告
+            System.err.println("Warning: Cannot configure batch settings, using defaults. " + e.getMessage());
         }
+
         lokiAppender.start();
 
         Logger rootLogger = context.getLogger("ROOT");
         rootLogger.addAppender(lokiAppender);
-
     }
 }