add VtDriver version metric (#146)

src/main/java/com/jd/jdbc/monitor/HealthCheckCollector.java

@@ -29,7 +29,7 @@
 import java.util.List;
 import java.util.Map;
 
-public final class HealthCheckCollector extends Collector {
+public final class HealthCheckCollector extends Collector implements Collector.Describable {
     private static final String COLLECT_NAME = "health_check";
 
     private static final String COLLECT_HELP = "healthByAlias info in HealthCheck";
@@ -92,4 +92,10 @@ public static void buildGaugeMetric(GaugeMetricFamily labeledGauge, TabletHealth
         long uid = tablet.getAlias().getUid();
         labeledGauge.addMetric(labelValues, tabletHealthCheck.getServing().get() ? uid : -uid);
     }
+
+    @Override
+    public List<MetricFamilySamples> describe() {
+        GaugeMetricFamily labeledGauge = new GaugeMetricFamily(COLLECT_NAME, COLLECT_HELP, DefaultConfig.HEALTH_CHECK_LABEL_NAMES);
+        return Collections.singletonList(labeledGauge);
+    }
 }

src/main/java/com/jd/jdbc/monitor/HealthyCollector.java

@@ -23,11 +23,12 @@
 import io.prometheus.client.Collector;
 import io.prometheus.client.GaugeMetricFamily;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 
-public final class HealthyCollector extends Collector {
+public final class HealthyCollector extends Collector implements Collector.Describable {
     private static final String COLLECT_NAME = "healthy";
 
     private static final String COLLECT_HELP = "healthy info in HealthCheck";
@@ -108,4 +109,9 @@ public static long stateHealthyChecksum(Map<String, List<TabletHealthCheck>> hea
         return Crc32Utill.checksumByCrc32(sb.toString().getBytes());
     }
 
+    @Override
+    public List<MetricFamilySamples> describe() {
+        GaugeMetricFamily labeledGauge = new GaugeMetricFamily(COLLECT_NAME, COLLECT_HELP, DefaultConfig.HEALTH_CHECK_LABEL_NAMES);
+        return Collections.singletonList(labeledGauge);
+    }
 }

src/main/java/com/jd/jdbc/monitor/SqlErrorCollector.java

@@ -40,7 +40,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
-public final class SqlErrorCollector extends Collector {
+public final class SqlErrorCollector extends Collector implements Collector.Describable {
     private static final Log LOG = LogFactory.getLog(SqlErrorCollector.class);
 
     private static final Integer DEFAULT_CAPACITY = 300;
@@ -135,6 +135,12 @@ public void add(final String keyspace, final String userSQL, final Map<String, B
         }
     }
 
+    @Override
+    public List<MetricFamilySamples> describe() {
+        GaugeMetricFamily labeledGauge = new GaugeMetricFamily(COLLECT_NAME, COLLECT_HELP, LABEL_NAMES);
+        return Collections.singletonList(labeledGauge);
+    }
+
     private static class Ignored {
         public static boolean match(final SQLException e) {
             return e instanceof SQLIntegrityConstraintViolationException

src/main/java/com/jd/jdbc/monitor/SrvKeyspaceCollector.java

@@ -29,7 +29,7 @@
 import java.util.List;
 import java.util.Map;
 
-public final class SrvKeyspaceCollector extends Collector {
+public final class SrvKeyspaceCollector extends Collector implements Collector.Describable {
     private static final List<String> LABEL_NAMES = Lists.newArrayList("Keyspace");
 
     private static final String COLLECT_NAME = "SrvKeyspaceCollector";
@@ -66,15 +66,15 @@ public final class SrvKeyspaceCollector extends Collector {
         .help("SrvKeyspaceTask update counter")
         .register(MonitorServer.getCollectorRegistry());
 
-    private static final SrvKeyspaceCollector srvKeyspaceCollector = new SrvKeyspaceCollector();
+    private static final SrvKeyspaceCollector SRV_KEYSPACE_COLLECTOR = new SrvKeyspaceCollector();
 
     private final List<ResilientServer> resilientServerList = new ArrayList<>();
 
     private SrvKeyspaceCollector() {
     }
 
     public static SrvKeyspaceCollector getInstance() {
-        return srvKeyspaceCollector;
+        return SRV_KEYSPACE_COLLECTOR;
     }
 
     public static Counter getCounter() {
@@ -122,4 +122,10 @@ public List<MetricFamilySamples> collect() {
     public void add(final ResilientServer resilientServer) {
         resilientServerList.add(resilientServer);
     }
+
+    @Override
+    public List<MetricFamilySamples> describe() {
+        GaugeMetricFamily labeledGauge = new GaugeMetricFamily(COLLECT_NAME, COLLECT_HELP, LABEL_NAMES);
+        return Collections.singletonList(labeledGauge);
+    }
 }

src/main/java/com/jd/jdbc/monitor/VersionCollector.java

@@ -0,0 +1,31 @@
+/*
+Copyright 2021 JD Project Authors.
+
+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 com.jd.jdbc.monitor;
+
+import io.prometheus.client.Gauge;
+
+public class VersionCollector {
+    private static final Gauge VTDRIVER_VERSION_COUNTER = Gauge.build()
+        .name("VtDriver_version")
+        .help("VtDriver version info")
+        .labelNames("version")
+        .register(MonitorServer.getCollectorRegistry());
+
+    public static Gauge getVersionGauge() {
+        return VTDRIVER_VERSION_COUNTER;
+    }
+}

src/main/java/com/jd/jdbc/vitess/metadata/VitessDatabaseMetaData.java

@@ -19,6 +19,7 @@
 import static com.jd.jdbc.common.Constant.DRIVER_MAJOR_VERSION;
 import static com.jd.jdbc.common.Constant.DRIVER_MINOR_VERSION;
 import static com.jd.jdbc.common.Constant.DRIVER_NAME;
+import com.jd.jdbc.monitor.VersionCollector;
 import com.jd.jdbc.pool.InnerConnection;
 import com.jd.jdbc.pool.StatefulConnectionPool;
 import com.jd.jdbc.queryservice.util.RoleUtils;
@@ -45,6 +46,7 @@ public class VitessDatabaseMetaData extends AbstractDatabaseMetaData {
             properties.load(VitessDatabaseMetaData.class.getClassLoader().getResourceAsStream("vtdriver-version.properties"));
             if (!properties.isEmpty()) {
                 version = properties.getProperty("version");
+                VersionCollector.getVersionGauge().labels(version).set(0);
             }
         } catch (IOException e) {
         }