Prometheus configurable queries

  allow externalized prometheus queries in a properties file

This resolves linkedin#1540

config/prometheus-query.properties

@@ -0,0 +1,10 @@
+# This file contains all the custom prometheus queries
+# This is an example property file for Kafka Cruise Control configurable prometheus queries.
+
+
+# =======================================
+# This must define all the queries for the different RawMetricType needed.
+# based on the schema <RAW_METRIC_TYPE>=query
+
+BROKER_CPU_UTIL=1 - avg by (instance) (irate(node_cpu_seconds_total{mode="idle"}[2m]))
+# ..

cruise-control/src/main/java/com/linkedin/kafka/cruisecontrol/monitor/sampling/prometheus/ConfigurablePrometheusQuerySupplier.java

@@ -0,0 +1,57 @@
+package com.linkedin.kafka.cruisecontrol.monitor.sampling.prometheus;
+
+import com.linkedin.cruisecontrol.common.CruiseControlConfigurable;
+import com.linkedin.kafka.cruisecontrol.metricsreporter.metric.RawMetricType;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+
+import static com.linkedin.cruisecontrol.common.utils.Utils.validateNotNull;
+import static com.linkedin.kafka.cruisecontrol.monitor.sampling.prometheus.PrometheusMetricSampler.PROMETHEUS_QUERY_FILE_CONFIG;
+
+/**
+ * Configurable prometheus query supplier. This needs a configuration file to specify the different
+ * prometheus metrics.
+ * <p>
+ * See {@link PrometheusQuerySupplier}
+ */
+public class ConfigurablePrometheusQuerySupplier implements CruiseControlConfigurable, PrometheusQuerySupplier {
+    private static final Map<RawMetricType, String> TYPE_TO_QUERY = new HashMap<>();
+
+    @Override
+    public Map<RawMetricType, String> get() {
+        return TYPE_TO_QUERY;
+    }
+
+    @Override
+    public void configure(Map<String, ?> configs) {
+        String configFileName = validateNotNull((String) configs.get(PROMETHEUS_QUERY_FILE_CONFIG),
+                "Prometheus configuration file is missing.");
+
+        internalParse(configFileName);
+    }
+
+    /**
+     * Parse the config file to fill in the map
+     * @param configFileName the name of the input config file
+     */
+    private void internalParse(String configFileName) {
+        Properties props = new Properties();
+        try (InputStream propStream = new FileInputStream(configFileName)) {
+            props.load(propStream);
+        } catch (IOException e) {
+            throw new IllegalArgumentException(e);
+        }
+
+        // load each entry of the properties into the internal map
+        props.forEach((key, value) -> loadEntry((String) key, (String) value));
+    }
+
+    private void loadEntry(String rawMetricTypeName, String query) {
+        // will throw a IllegalArgumentException if the name is unknown in the RawMetricType enum
+        TYPE_TO_QUERY.put(RawMetricType.valueOf(rawMetricTypeName), query);
+    }
+}

cruise-control/src/main/java/com/linkedin/kafka/cruisecontrol/monitor/sampling/prometheus/PrometheusMetricSampler.java

@@ -59,7 +59,10 @@ public class PrometheusMetricSampler extends AbstractMetricSampler {
 
     // Config name visible to tests
     static final String PROMETHEUS_QUERY_SUPPLIER_CONFIG = "prometheus.query.supplier";
+    static final String PROMETHEUS_QUERY_FILE_CONFIG = "prometheus.query.file";
+
     private static final Class<?> DEFAULT_PROMETHEUS_QUERY_SUPPLIER = DefaultPrometheusQuerySupplier.class;
+    private static final Class<?> PROMETHEUS_QUERY_FILE_SUPPLIER = ConfigurablePrometheusQuerySupplier.class;
 
     private static final Logger LOG = LoggerFactory.getLogger(PrometheusMetricSampler.class);
 
@@ -120,15 +123,21 @@ private void configurePrometheusAdapter(Map<String, ?> configs) {
     }
 
     private void configureQueryMap(Map<String, ?> configs) {
+        String prometheusQueryFileName = (String) configs.get(PROMETHEUS_QUERY_FILE_CONFIG);
         String prometheusQuerySupplierClassName = (String) configs.get(PROMETHEUS_QUERY_SUPPLIER_CONFIG);
         Class<?> prometheusQuerySupplierClass = DEFAULT_PROMETHEUS_QUERY_SUPPLIER;
-        if (prometheusQuerySupplierClassName != null) {
-            prometheusQuerySupplierClass = (Class<?>) ConfigDef.parseType(PROMETHEUS_QUERY_SUPPLIER_CONFIG,
-                prometheusQuerySupplierClassName, CLASS);
-            if (!PrometheusQuerySupplier.class.isAssignableFrom(prometheusQuerySupplierClass)) {
-                throw new ConfigException(String.format(
-                    "Invalid %s is provided to prometheus metric sampler, provided %s",
-                    PROMETHEUS_QUERY_SUPPLIER_CONFIG, prometheusQuerySupplierClass));
+        // prometheus configuration file is first over other custom or default query supplier class
+        if (null != prometheusQueryFileName) {
+            prometheusQuerySupplierClass = PROMETHEUS_QUERY_FILE_SUPPLIER;
+        } else {
+            if (prometheusQuerySupplierClassName != null) {
+                prometheusQuerySupplierClass = (Class<?>) ConfigDef.parseType(PROMETHEUS_QUERY_SUPPLIER_CONFIG,
+                        prometheusQuerySupplierClassName, CLASS);
+                if (!PrometheusQuerySupplier.class.isAssignableFrom(prometheusQuerySupplierClass)) {
+                    throw new ConfigException(String.format(
+                            "Invalid %s is provided to prometheus metric sampler, provided %s",
+                            PROMETHEUS_QUERY_SUPPLIER_CONFIG, prometheusQuerySupplierClass));
+                }
             }
         }
         PrometheusQuerySupplier prometheusQuerySupplier = KafkaCruiseControlConfigUtils.getConfiguredInstance(

cruise-control/src/test/java/com/linkedin/kafka/cruisecontrol/monitor/sampling/prometheus/PrometheusMetricSamplerTest.java

@@ -169,6 +169,44 @@ public void testGetSamplesPrometheusQuerySupplierInvalidClass() throws Exception
         _prometheusMetricSampler.configure(config);
     }
 
+    @Test
+    public void testGetSamplesCustomPrometheusQueryFile() throws Exception {
+        Map<String, Object> config = new HashMap<>();
+        config.put(PROMETHEUS_SERVER_ENDPOINT_CONFIG, "http://kafka-cluster-1.org:9090");
+        addCapacityConfig(config);
+        config.put(PROMETHEUS_QUERY_FILE_CONFIG, this.getClass().getClassLoader().getResource("prometheusQueriesTest.properties").getFile());
+        _prometheusMetricSampler.configure(config);
+
+        MetricSamplerOptions metricSamplerOptions = buildMetricSamplerOptions(TEST_TOPIC);
+        _prometheusMetricSampler._prometheusAdapter = _prometheusAdapter;
+
+        expect(_prometheusAdapter.queryMetric(eq(TestQuerySupplier.TEST_QUERY), anyLong(), anyLong()))
+                .andReturn(buildBrokerResults());
+        replay(_prometheusAdapter);
+
+        _prometheusMetricSampler.getSamples(metricSamplerOptions);
+
+        verify(_prometheusAdapter);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetSamplesCustomPrometheusQueryFileNotFoundFile() throws Exception {
+        Map<String, Object> config = new HashMap<>();
+        config.put(PROMETHEUS_SERVER_ENDPOINT_CONFIG, "http://kafka-cluster-1.org:9090");
+        addCapacityConfig(config);
+        config.put(PROMETHEUS_QUERY_FILE_CONFIG, "/a/b/file.properties");
+        _prometheusMetricSampler.configure(config);
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void testGetSamplesCustomPrometheusQueryFileUnknownMetricType() throws Exception {
+        Map<String, Object> config = new HashMap<>();
+        config.put(PROMETHEUS_SERVER_ENDPOINT_CONFIG, "http://kafka-cluster-1.org:9090");
+        addCapacityConfig(config);
+        config.put(PROMETHEUS_QUERY_FILE_CONFIG, this.getClass().getClassLoader().getResource("prometheusQueriesTestFailing.properties").getFile());
+        _prometheusMetricSampler.configure(config);
+    }
+
     private static MetricSamplerOptions buildMetricSamplerOptions(String topic) {
 
         return new MetricSamplerOptions(

cruise-control/src/test/resources/prometheusQueriesTest.properties

@@ -0,0 +1 @@
+ALL_TOPIC_BYTES_IN=test_query

cruise-control/src/test/resources/prometheusQueriesTestFailing.properties

@@ -0,0 +1,2 @@
+ALL_TOPIC_BYTES_IN=test_query
+Unknown="I don't know"

docs/wiki/User Guide/Configurations.md

@@ -298,6 +298,7 @@ We are still trying to improve cruise control. And following are some configurat
 | prometheus.server.endpoint                           | String  | Y         |                                                                                             | The HTTP endpoint of the Prometheus server which is to be used as a source for sampling metrics.                                                                                                           |
 | prometheus.query.resolution.step.ms                  | Integer | N         | 60,000                                                                                      | The resolution of the Prometheus query made to the server. If this is set to 30 seconds for a 2 minutes query interval, the query returns with 4 values, which are then aggregated into the metric sample. |
 | prometheus.query.supplier                            | Class   | N         | com.linkedin.kafka.cruisecontrol.monitor.sampling.prometheus.DefaultPrometheusQuerySupplier | The class that supplies the Prometheus queries corresponding to Kafka raw metrics. If there are no customizations done when configuring Prometheus node exporter, the default class should work fine.      |
+| prometheus.query.file                                | String  | N         |                                                                                             | The configuration file supplying the custom Prometheus queries corresponding to Kafka raw metrics. Takes precedence over prometheus.query.supplier.                                                        |
 | prometheus.broker.metrics.scraping.frequency.seconds | Integer | N         | 60                                                                                          | The scraping frequency with which Prometheus scrapes metrics from Kafka brokers. This value is used by DefaultPrometheusQuerySupplier to construct the iRate query that is used to get broker cpu metrics. |
 ### KafkaSampleStore configurations
 | Name                                                  | Type    | Required? | Default Value | Description                                                                                                                                                                                             |