Add environment (system/container) memory metrics

micrometer-core/src/main/java/io/micrometer/core/instrument/binder/system/MemoryMetrics.java

@@ -0,0 +1,174 @@
+/*
+ * Copyright 2017 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.core.instrument.binder.system;
+
+import io.micrometer.common.lang.NonNullApi;
+import io.micrometer.common.lang.NonNullFields;
+import io.micrometer.common.lang.Nullable;
+import io.micrometer.core.instrument.*;
+import io.micrometer.core.instrument.binder.BaseUnits;
+import io.micrometer.core.instrument.binder.MeterBinder;
+
+import java.lang.management.*;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.List;
+
+import static java.util.Collections.emptyList;
+import static java.util.Objects.requireNonNull;
+
+/**
+ * Record metrics that report memory usage.
+ *
+ * @author Fábio C. Martins
+ */
+@NonNullApi
+@NonNullFields
+public class MemoryMetrics implements MeterBinder {
+
+    /**
+     * List of public, exported interface class names from supported JVM implementations.
+     */
+    private static final List<String> OPERATING_SYSTEM_BEAN_CLASS_NAMES = Arrays.asList(
+            "com.ibm.lang.management.OperatingSystemMXBean", // J9
+            "com.sun.management.OperatingSystemMXBean" // HotSpot
+    );
+
+    private final OperatingSystemMXBean operatingSystemBean;
+
+    @Nullable
+    private final Class<?> operatingSystemBeanClass;
+
+    private final Iterable<Tag> tags;
+
+    @Nullable
+    private final Method committedVirtualMemorySize;
+
+    @Nullable
+    private final Method totalSwapSpaceSize;
+
+    @Nullable
+    private final Method freeSwapSpaceSize;
+
+    @Nullable
+    private final Method freePhysicalMemorySize;
+
+    @Nullable
+    private final Method totalPhysicalMemorySize;
+
+    public MemoryMetrics() {
+        this(emptyList());
+    }
+
+    public MemoryMetrics(Iterable<Tag> tags) {
+        this.tags = tags;
+        this.operatingSystemBean = ManagementFactory.getOperatingSystemMXBean();
+        this.operatingSystemBeanClass = getFirstClassFound(OPERATING_SYSTEM_BEAN_CLASS_NAMES);
+        this.committedVirtualMemorySize = detectMethod("getCommittedVirtualMemorySize");
+        this.totalSwapSpaceSize = detectMethod("getTotalSwapSpaceSize");
+        this.freeSwapSpaceSize = detectMethod("getFreeSwapSpaceSize");
+        this.freePhysicalMemorySize = detectMethod("getFreePhysicalMemorySize");
+        this.totalPhysicalMemorySize = detectMethod("getTotalPhysicalMemorySize");
+    }
+
+    @Override
+    public void bindTo(MeterRegistry registry) {
+        Runtime runtime = Runtime.getRuntime();
+        if (committedVirtualMemorySize != null) {
+            Gauge.builder("system.virtualmemory.commited", operatingSystemBean, x -> invoke(committedVirtualMemorySize))
+                .tags(tags)
+                .baseUnit(BaseUnits.BYTES)
+                .description(
+                        "The amount of virtual memory in bytes that is commited for the Java virtual machine to use")
+                .register(registry);
+        }
+
+        if (totalSwapSpaceSize != null) {
+            Gauge.builder("system.swap.total", operatingSystemBean, x -> invoke(totalSwapSpaceSize))
+                .tags(tags)
+                .baseUnit(BaseUnits.BYTES)
+                .description("The total amount of swap space in bytes")
+                .register(registry);
+        }
+
+        if (freeSwapSpaceSize != null) {
+            Gauge.builder("system.swap.free", operatingSystemBean, x -> invoke(freeSwapSpaceSize))
+                .tags(tags)
+                .baseUnit(BaseUnits.BYTES)
+                .description("The amount of free swap space in bytes")
+                .register(registry);
+        }
+
+        if (freePhysicalMemorySize != null) {
+            Gauge.builder("system.memory.free", operatingSystemBean, x -> invoke(freePhysicalMemorySize))
+                .tags(tags)
+                .baseUnit(BaseUnits.BYTES)
+                .description("The amount of free physical memory in bytes")
+                .register(registry);
+        }
+
+        if (totalPhysicalMemorySize != null) {
+            Gauge.builder("system.memory.total", operatingSystemBean, x -> invoke(totalPhysicalMemorySize))
+                .tags(tags)
+                .baseUnit(BaseUnits.BYTES)
+                .description("The total amount of physical memory in  bytes")
+                .register(registry);
+        }
+    }
+
+    private double invoke(@Nullable Method method) {
+        try {
+            return method != null ? toDouble((Number) method.invoke(operatingSystemBean)) : Double.NaN;
+        }
+        catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
+            return Double.NaN;
+        }
+    }
+
+    private double toDouble(@Nullable Number number) {
+        return number != null ? number.doubleValue() : Double.NaN;
+    }
+
+    @Nullable
+    private Method detectMethod(String name) {
+        requireNonNull(name);
+        if (operatingSystemBeanClass == null) {
+            return null;
+        }
+        try {
+            // ensure the Bean we have is actually an instance of the interface
+            operatingSystemBeanClass.cast(operatingSystemBean);
+            return operatingSystemBeanClass.getMethod(name);
+        }
+        catch (ClassCastException | NoSuchMethodException | SecurityException e) {
+            return null;
+        }
+    }
+
+    @Nullable
+    private Class<?> getFirstClassFound(List<String> classNames) {
+        for (String className : classNames) {
+            try {
+                return Class.forName(className);
+            }
+            catch (ClassNotFoundException ignore) {
+            }
+        }
+        return null;
+    }
+
+}

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/system/MemoryMetricsTest.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2017 VMware, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micrometer.core.instrument.binder.system;
+
+import io.micrometer.core.instrument.Gauge;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.binder.BaseUnits;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Assumptions.assumeFalse;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
+
+/**
+ * Tests for {@link MemoryMetrics}.
+ *
+ * @author Fábio C. Martins
+ */
+class MemoryMetricsTest {
+
+    MeterRegistry registry = new SimpleMeterRegistry();
+
+    @BeforeEach
+    void setup() {
+        new MemoryMetrics().bindTo(registry);
+    }
+
+    @Test
+    void memoryMetrics() {
+        Gauge virtualMemCommited = registry.get("system.virtualmemory.commited").gauge();
+        assertThat(virtualMemCommited.getId().getBaseUnit()).isEqualTo(BaseUnits.BYTES);
+
+        Gauge swapTotal = registry.get("system.swap.total").gauge();
+        assertThat(swapTotal.value()).isNotNegative();
+        assertThat(swapTotal.getId().getBaseUnit()).isEqualTo(BaseUnits.BYTES);
+
+        Gauge swapFree = registry.get("system.swap.free").gauge();
+        assertThat(swapFree.value()).isNotNegative();
+        assertThat(swapFree.getId().getBaseUnit()).isEqualTo(BaseUnits.BYTES);
+
+        Gauge memFree = registry.get("system.memory.free").gauge();
+        assertThat(memFree.getId().getBaseUnit()).isEqualTo(BaseUnits.BYTES);
+
+        Gauge memTotal = registry.get("system.memory.total").gauge();
+        assertThat(memTotal.value()).isNotNegative();
+        assertThat(memTotal.getId().getBaseUnit()).isEqualTo(BaseUnits.BYTES);
+    }
+
+    @Test
+    void hotspotMetrics() {
+        assumeFalse(isOpenJ9());
+        assertThat(registry.get("system.virtualmemory.commited").gauge().value()).isNotNegative();
+        assertThat(registry.get("system.memory.free").gauge().value()).isNotNegative();
+    }
+
+    @Test
+    void j9Metrics() {
+        assumeTrue(isOpenJ9());
+
+        assertThat(registry.get("system.virtualmemory.commited").gauge().value()).isGreaterThanOrEqualTo(-1);
+        assertThat(registry.get("system.memory.free").gauge().value()).isGreaterThanOrEqualTo(-1);
+    }
+
+    private boolean isOpenJ9() {
+        return classExists("com.ibm.lang.management.OperatingSystemMXBean");
+    }
+
+    private boolean classExists(String className) {
+        try {
+            Class.forName(className);
+            return true;
+        }
+        catch (ClassNotFoundException e) {
+            return false;
+        }
+    }
+
+}