From 92b41b680a1b147908196d59091a5f117d8a57fb Mon Sep 17 00:00:00 2001
From: coderzc <zhaocong@apache.org>
Date: Thu, 28 Jul 2022 16:10:53 +0800
Subject: [PATCH] Use reflection to get metrics

---
 pom.xml                                       |  3 --
 .../broker/loadbalance/LinuxInfoUtils.java    | 42 +++++++++++++++----
 .../loadbalance/SimpleBrokerStartTest.java    |  3 +-
 3 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/pom.xml b/pom.xml
index 9e0b82f866fb9d..e956c06b957d97 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1772,9 +1772,6 @@ flexible messaging model and an intuitive client API.</description>
           <version>${maven-compiler-plugin.version}</version>
           <configuration>
             <release>${pulsar.broker.compiler.release}</release>
-            <compilerArgs>
-              <arg>--add-opens java.base/jdk.internal.platform=ALL-UNNAMED</arg>
-            </compilerArgs>
           </configuration>
         </plugin>
         <plugin>
diff --git a/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/LinuxInfoUtils.java b/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/LinuxInfoUtils.java
index d5c1dabf68c3eb..c4142809605ac5 100644
--- a/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/LinuxInfoUtils.java
+++ b/pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/LinuxInfoUtils.java
@@ -20,6 +20,7 @@
 
 import com.google.common.base.Charsets;
 import java.io.IOException;
+import java.lang.reflect.Method;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -29,11 +30,10 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import jdk.internal.platform.Container;
-import jdk.internal.platform.Metrics;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
+import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.lang3.SystemUtils;
@@ -49,10 +49,29 @@ public class LinuxInfoUtils {
     private static final int ARPHRD_ETHER = 1;
     private static final String NIC_SPEED_TEMPLATE = "/sys/class/net/%s/speed";
 
-    private static final Metrics METRICS;
+    private static Object /*jdk.internal.platform.Metrics*/ metrics;
+    private static Method getMetricsProviderMethod;
+    private static Method getCpuQuotaMethod;
+    private static Method getCpuPeriodMethod;
+    private static Method getCpuUsageMethod;
 
     static {
-        METRICS = Container.metrics();
+        try {
+            metrics = Class.forName("jdk.internal.platform.Container").getMethod("metrics")
+                    .invoke(null);
+            if (metrics != null) {
+                getMetricsProviderMethod = metrics.getClass().getMethod("getProvider");
+                getMetricsProviderMethod.setAccessible(true);
+                getCpuQuotaMethod = metrics.getClass().getMethod("getCpuQuota");
+                getCpuQuotaMethod.setAccessible(true);
+                getCpuPeriodMethod = metrics.getClass().getMethod("getCpuPeriod");
+                getCpuPeriodMethod.setAccessible(true);
+                getCpuUsageMethod = metrics.getClass().getMethod("getCpuUsage");
+                getCpuUsageMethod.setAccessible(true);
+            }
+        } catch (Throwable e) {
+            log.warn("Failed to get runtime metrics", e);
+        }
     }
 
     /**
@@ -68,10 +87,10 @@ public static boolean isLinux() {
      */
     public static boolean isCGroupEnabled() {
         try {
-            if (METRICS == null) {
+            if (metrics == null) {
                 return false;
             }
-            String provider = METRICS.getProvider();
+            String provider = (String) getMetricsProviderMethod.invoke(metrics);
             log.info("[LinuxInfo] The system metrics provider is: {}", provider);
             return provider.contains("cgroup");
         } catch (Exception e) {
@@ -85,10 +104,11 @@ public static boolean isCGroupEnabled() {
      * @param isCGroupsEnabled Whether CGroup is enabled
      * @return Total cpu limit
      */
+    @SneakyThrows
     public static double getTotalCpuLimit(boolean isCGroupsEnabled) {
         if (isCGroupsEnabled) {
-            long quota = METRICS.getCpuQuota();
-            long period = METRICS.getCpuPeriod();
+            long quota = (long) getCpuQuotaMethod.invoke(metrics);
+            long period = (long) getCpuPeriodMethod.invoke(metrics);
             if (quota > 0) {
                 return 100.0 * quota / period;
             }
@@ -101,8 +121,12 @@ public static double getTotalCpuLimit(boolean isCGroupsEnabled) {
      * Get CGroup cpu usage.
      * @return Cpu usage
      */
+    @SneakyThrows
     public static double getCpuUsageForCGroup() {
-        return METRICS.getCpuUsage();
+        if (getCpuUsageMethod == null) {
+            return  -1;
+        }
+        return (double) getCpuUsageMethod.invoke(metrics);
     }
 
 
diff --git a/pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/SimpleBrokerStartTest.java b/pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/SimpleBrokerStartTest.java
index 143c431e8728a7..1506e0bc2cb481 100644
--- a/pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/SimpleBrokerStartTest.java
+++ b/pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/SimpleBrokerStartTest.java
@@ -29,7 +29,6 @@
 import java.util.Optional;
 import lombok.Cleanup;
 import lombok.extern.slf4j.Slf4j;
-import org.apache.commons.lang3.SystemUtils;
 import org.apache.pulsar.broker.PulsarServerException;
 import org.apache.pulsar.broker.PulsarService;
 import org.apache.pulsar.broker.ServiceConfiguration;
@@ -106,7 +105,7 @@ public void testNoNICSpeed() throws Exception {
 
     @Test
     public void testCGroupMetrics() throws IOException {
-        if (!SystemUtils.IS_OS_LINUX) {
+        if (!LinuxInfoUtils.isLinux()) {
             return;
         }