Support setting flush interval of the metric log via SentinelConfig property

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

@@ -55,12 +55,14 @@ public final class SentinelConfig {
     public static final String COLD_FACTOR = "csp.sentinel.flow.cold.factor";
     public static final String STATISTIC_MAX_RT = "csp.sentinel.statistic.max.rt";
     public static final String SPI_CLASSLOADER = "csp.sentinel.spi.classloader";
+    public static final String METRIC_FLUSH_INTERVAL = "csp.sentinel.metric.flush.interval";
 
     public static final String DEFAULT_CHARSET = "UTF-8";
     public static final long DEFAULT_SINGLE_METRIC_FILE_SIZE = 1024 * 1024 * 50;
     public static final int DEFAULT_TOTAL_METRIC_FILE_COUNT = 6;
     public static final int DEFAULT_COLD_FACTOR = 3;
     public static final int DEFAULT_STATISTIC_MAX_RT = 5000;
+    public static final long DEFAULT_METRIC_FLUSH_INTERVAL = 1L;
 
     static {
         try {
@@ -98,6 +100,7 @@ private static void initialize() {
         setConfig(TOTAL_METRIC_FILE_COUNT, String.valueOf(DEFAULT_TOTAL_METRIC_FILE_COUNT));
         setConfig(COLD_FACTOR, String.valueOf(DEFAULT_COLD_FACTOR));
         setConfig(STATISTIC_MAX_RT, String.valueOf(DEFAULT_STATISTIC_MAX_RT));
+        setConfig(METRIC_FLUSH_INTERVAL, String.valueOf(DEFAULT_METRIC_FLUSH_INTERVAL));
     }
 
     private static void loadProps() {
@@ -155,6 +158,24 @@ public static int getAppType() {
     public static String charset() {
         return props.get(CHARSET);
     }
+
+    /**
+     * Get the metric log flush interval in second
+     * @return  the metric log flush interval in second
+     */
+    public static long metricLogFlushIntervalSec() {
+        String flushIntervalStr = SentinelConfig.getConfig(METRIC_FLUSH_INTERVAL);
+        if (flushIntervalStr == null) {
+            return DEFAULT_METRIC_FLUSH_INTERVAL;
+        }
+        try {
+            return Long.parseLong(flushIntervalStr);
+        } catch (Throwable throwable) {
+            RecordLog.warn("[SentinelConfig] Parse the metricLogFlushInterval fail, use default value: "
+                    + DEFAULT_METRIC_FLUSH_INTERVAL, throwable);
+            return DEFAULT_METRIC_FLUSH_INTERVAL;
+        }
+    }
 
     public static long singleMetricFileSize() {
         try {

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/FlowRuleManager.java

@@ -26,6 +26,7 @@
 import java.util.concurrent.atomic.AtomicReference;
 
 import com.alibaba.csp.sentinel.concurrent.NamedThreadFactory;
+import com.alibaba.csp.sentinel.config.SentinelConfig;
 import com.alibaba.csp.sentinel.log.RecordLog;
 import com.alibaba.csp.sentinel.util.AssertUtil;
 import com.alibaba.csp.sentinel.util.StringUtil;
@@ -61,9 +62,29 @@ public class FlowRuleManager {
     static {
         flowRules.set(Collections.<String, List<FlowRule>>emptyMap());
         currentProperty.addListener(LISTENER);
-        SCHEDULER.scheduleAtFixedRate(new MetricTimerListener(), 0, 1, TimeUnit.SECONDS);
+        startMetricTimerListener();
     }
-
+
+    /**
+     * <p> Start the MetricTimerListener
+     * <ol>
+     *     <li>If the flushInterval more than 0,
+     * the timer will run with the flushInterval as the rate </li>.
+     *      <li>If the flushInterval less than 0(include) or value is not valid,
+     * then means the timer will not be started </li>
+     * <ol></p>
+     */
+    private static void startMetricTimerListener() {
+        long flushInterval = SentinelConfig.metricLogFlushIntervalSec();
+        if (flushInterval <= 0) {
+            RecordLog.info("[FlowRuleManager] The MetricTimerListener is'n started. If you want to start it, "
+                    + "please change the value(current: {}) of config({}) more than 0 to start it.", flushInterval,
+                    SentinelConfig.METRIC_FLUSH_INTERVAL);
+            return;
+        }
+        SCHEDULER.scheduleAtFixedRate(new MetricTimerListener(), 0, flushInterval, TimeUnit.SECONDS);
+    }
+
     /**
      * Listen to the {@link SentinelProperty} for {@link FlowRule}s. The property is the source of {@link FlowRule}s.
      * Flow rules can also be set by {@link #loadRules(List)} directly.