[ONOS-3536] Implement back-end metrics saving logic using RRD

Change-Id: I1b3c495380884571dc88d2f9fb3152fdf41ef655

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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
+ *
+ *     http://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 org.onosproject.cpman;
+
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Database for storing a metric.
+ */
+public interface MetricsDatabase {
+    /**
+     * Returns the metric name of this database.
+     *
+     * @return metric name
+     */
+    String metricName();
+
+    /**
+     * Update metric value by specifying metric type.
+     *
+     * @param metricType metric type (e.g., load, usage, etc.)
+     * @param value metric value
+     */
+    void updateMetric(String metricType, double value);
+
+    /**
+     * Update metric value by specifying metric type in a certain time.
+     *
+     * @param metricType metric type (e.g., load, usage, etc.)
+     * @param value metric value
+     * @param time update time in seconds
+     */
+    void updateMetric(String metricType, double value, long time);
+
+    /**
+     * Update metric values of a collection of metric types.
+     *
+     * @param metrics a collection of metrics which consists of a pair of
+     *                metric type and metric value
+     * @param time    update time in seconds
+     */
+    void updateMetrics(Map<String, Double> metrics, long time);
+
+    /**
+     * Update metric values of a collection of metric types.
+     *
+     * @param metrics a collection of metrics which consists of a pair of
+     *                metric type and metric value
+     */
+    void updateMetrics(Map<String, Double> metrics);
+
+    /**
+     * Returns most recent metric value of a given metric type.
+     *
+     * @param metricType metric type
+     * @return metric value
+     */
+    double recentMetric(String metricType);
+
+    /**
+     * Return most recent metric values of a given metric type for a given period.
+     *
+     * @param metricType metric type
+     * @param duration duration
+     * @param unit time unit
+     * @return a collection of metric value
+     */
+    double[] recentMetrics(String metricType, int duration, TimeUnit unit);
+
+    /**
+     * Returns minimum metric value of a given metric type.
+     *
+     * @param metricType metric type
+     * @return metric value
+     */
+    double minMetric(String metricType);
+
+    /**
+     * Returns maximum metric value of a given metric type.
+     *
+     * @param metricType metric type
+     * @return metric value
+     */
+    double maxMetric(String metricType);
+
+    /**
+     * Returns a collection of metric values of a given metric type for a day.
+     *
+     * @param metricType metric type
+     * @return a collection of metric value
+     */
+    double[] metrics(String metricType);
+
+    /**
+     * Returns a collection of metric values of a given metric type for
+     * a given period.
+     *
+     * @param metricType metric type
+     * @param startTime start time
+     * @param endTime end time
+     * @return a collection of metric value
+     */
+    double[] metrics(String metricType, long startTime, long endTime);
+
+    /**
+     * A builder of MetricsDatabase.
+     */
+    interface Builder {
+
+        /**
+         * Sets the metric name.
+         *
+         * @param metricName metric name
+         * @return builder object
+         */
+        Builder withMetricName(String metricName);
+
+        /**
+         * Add a new metric to be monitored.
+         *
+         * @param metricType control metric type
+         */
+        Builder addMetricType(String metricType);
+
+        /**
+         * Builds a MetricDatabase instance.
+         *
+         * @return MetricDatabase instance
+         */
+        MetricsDatabase build();
+    }
+}

@@ -105,6 +105,11 @@
             <version>1.1.1</version>
         </dependency>
         <dependency>
+            <groupId>org.rrd4j</groupId>
+            <artifactId>rrd4j</artifactId>
+            <version>2.2</version>
+        </dependency>
+        <dependency>
             <groupId>com.sun.jersey</groupId>
             <artifactId>jersey-servlet</artifactId>
         </dependency>

@@ -43,7 +43,6 @@ public class ControlPlaneMonitor implements ControlPlaneMonitorService {
 
     @Activate
     public void activate() {
-
     }
 
     @Deactivate
@@ -53,6 +52,7 @@ public class ControlPlaneMonitor implements ControlPlaneMonitorService {
     @Override
     public void updateMetric(ControlMetric cpm, Integer updateInterval,
                              Optional<DeviceId> deviceId) {
+
     }
 
     @Override

+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * 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
+ *
+ *     http://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 org.onosproject.cpman.impl;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.onosproject.cpman.MetricsDatabase;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Unit test for control plane metrics back-end database.
+ */
+public class MetricsDatabaseTest {
+
+    private MetricsDatabase mdb;
+    private static final String CPU_METRIC = "cpu";
+    private static final String CPU_LOAD = "load";
+    private static final String MEMORY_METRIC = "memory";
+    private static final String MEMORY_FREE_PERC = "freePerc";
+    private static final String MEMORY_USED_PERC = "usedPerc";
+
+    /**
+     * Initializes the MetricsDatabase instance.
+     */
+    @Before
+    public void setUp() {
+        mdb = new DefaultMetricsDatabase.Builder()
+                .withMetricName(CPU_METRIC)
+                .addMetricType(CPU_LOAD)
+                .build();
+    }
+
+    /**
+     * Tests the metric update function.
+     */
+    @Test
+    public void testMetricUpdate() {
+        long currentTime = System.currentTimeMillis() / 1000L;
+
+        mdb.updateMetric(CPU_LOAD, 30, currentTime);
+        assertThat(30D, is(mdb.recentMetric(CPU_LOAD)));
+
+        mdb.updateMetric(CPU_LOAD, 40, currentTime + 60);
+        assertThat(40D, is(mdb.recentMetric(CPU_LOAD)));
+
+        mdb.updateMetric(CPU_LOAD, 50, currentTime + 120);
+        assertThat(50D, is(mdb.recentMetric(CPU_LOAD)));
+    }
+
+    /**
+     * Tests the metric range fetch function.
+     */
+    @Test
+    public void testMetricRangeFetch() {
+        // full range fetch
+        assertThat(mdb.metrics(CPU_LOAD).length, is(60 * 24));
+
+        // query one minute time range
+        assertThat(mdb.recentMetrics(CPU_LOAD, 1, TimeUnit.MINUTES).length, is(1));
+
+        // query one hour time range
+        assertThat(mdb.recentMetrics(CPU_LOAD, 1, TimeUnit.HOURS).length, is(60));
+
+        // query one day time range
+        assertThat(mdb.recentMetrics(CPU_LOAD, 1, TimeUnit.DAYS).length, is(60 * 24));
+
+        // query a specific time range
+        long endTime = System.currentTimeMillis() / 1000L;
+        long startTime = endTime - 60 * 5;
+        assertThat(mdb.metrics(CPU_LOAD, startTime, endTime).length, is(5));
+    }
+
+    /**
+     * Test the projected time range.
+     */
+    @Test(expected = IllegalArgumentException.class)
+    public void testExceededTimeRange() {
+        // query 25 hours time range
+        assertThat(mdb.recentMetrics(CPU_LOAD, 25, TimeUnit.HOURS).length, is(60 * 24));
+    }
+
+    /**
+     * Test the projected time range.
+     */
+    @Test(expected = IllegalArgumentException.class)
+    public void testInsufficientTimeRange() {
+        // query 50 seconds time range
+        assertThat(mdb.recentMetrics(CPU_LOAD, 50, TimeUnit.SECONDS).length, is(1));
+    }
+
+    /**
+     * Test multiple metrics update and query.
+     */
+    @Test
+    public void testMultipleMetrics() {
+        MetricsDatabase multiMdb = new DefaultMetricsDatabase.Builder()
+                        .withMetricName(MEMORY_METRIC)
+                        .addMetricType(MEMORY_FREE_PERC)
+                        .addMetricType(MEMORY_USED_PERC)
+                        .build();
+
+        Map<String, Double> metrics = new HashMap<>();
+        metrics.putIfAbsent(MEMORY_FREE_PERC, 30D);
+        metrics.putIfAbsent(MEMORY_USED_PERC, 70D);
+        multiMdb.updateMetrics(metrics);
+
+        assertThat(30D, is(multiMdb.recentMetric(MEMORY_FREE_PERC)));
+        assertThat(70D, is(multiMdb.recentMetric(MEMORY_USED_PERC)));
+    }
+}