feat: #WB-3251, expose ent version as metrics

Author: juniorode

infra/src/main/java/org/entcore/infra/Starter.java

@@ -27,6 +27,7 @@
 import io.vertx.core.DeploymentOptions;
 import io.vertx.core.eventbus.MessageConsumer;
 import io.vertx.core.json.JsonArray;
+import io.vertx.core.metrics.MetricsOptions;
 import io.vertx.core.shareddata.AsyncMap;
 import io.vertx.core.shareddata.LocalMap;
 import org.entcore.common.email.EmailFactory;
@@ -37,6 +38,7 @@
 import org.entcore.infra.controllers.*;
 import org.entcore.infra.cron.HardBounceTask;
 import org.entcore.infra.cron.MonitoringEventsChecker;
+import org.entcore.infra.metrics.MicrometerInfraMetricsRecorder;
 import org.entcore.infra.services.EventStoreService;
 import org.entcore.infra.services.impl.ClamAvService;
 import org.entcore.infra.services.impl.ExecCommandWorker;
@@ -225,6 +227,20 @@ public void start() {
 			);
 			vertx.setPeriodic(checkMonitoringEvents.getLong("period", 300000L), monitoringEventsChecker);
 		}
+		final boolean metricsActivated;
+		if(config.getJsonObject("metricsOptions") == null) {
+			final String metricsOptions = (String) vertx.sharedData().getLocalMap("server").get("metricsOptions");
+			if(metricsOptions == null){
+				metricsActivated = false;
+			}else{
+				metricsActivated = new MetricsOptions(new JsonObject(metricsOptions)).isEnabled();
+			}
+		} else {
+			metricsActivated = new MetricsOptions(config.getJsonObject("metricsOptions")).isEnabled();
+		}
+		if(metricsActivated) {
+			new MicrometerInfraMetricsRecorder(vertx);
+		}
 	}
 
 	private void loadInvalidEmails() {

infra/src/main/java/org/entcore/infra/metrics/InfraMetricsRecorder.java

@@ -0,0 +1,7 @@
+package org.entcore.infra.metrics;
+
+public interface InfraMetricsRecorder {
+  class NoopInfraMetricsRecorder implements InfraMetricsRecorder {
+    public static final InfraMetricsRecorder instance = new NoopInfraMetricsRecorder();
+  }
+}

infra/src/main/java/org/entcore/infra/metrics/MicrometerInfraMetricsRecorder.java

@@ -0,0 +1,70 @@
+package org.entcore.infra.metrics;
+
+import io.micrometer.core.instrument.Gauge;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.vertx.core.Vertx;
+import io.vertx.core.logging.Logger;
+import io.vertx.core.logging.LoggerFactory;
+import io.vertx.core.shareddata.LocalMap;
+import io.vertx.micrometer.backends.BackendRegistries;
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.apache.commons.lang3.StringUtils.isNotEmpty;
+
+/**
+ * Supplies the metric 'ent.version' that contains a codified version of the ENT.
+ * It takes the value of "ent-version" from the configuration and then applies the following transformation :
+ * - only numbers, hyphens and dots are preserved
+ * - each group of digits between hyphens and dots are grouped together, right-padded with 0 if needed
+ *  - the groups are "concatenated" together and parsed to a long to get the exposed metric.
+ *  The metric is tagged with the version as specified in the configuration.
+ */
+public class MicrometerInfraMetricsRecorder implements InfraMetricsRecorder {
+  private static final Logger log = LoggerFactory.getLogger(MicrometerInfraMetricsRecorder.class);
+  private static final int VERSION_PADDING = 2;
+  public MicrometerInfraMetricsRecorder(final Vertx vertx) {
+    final MeterRegistry registry = BackendRegistries.getDefaultNow();
+    if(registry == null) {
+      throw new IllegalStateException("micrometer.registries.empty");
+    }
+    String literalVersion;
+    final AtomicLong version = new AtomicLong();
+    try {
+      literalVersion = getLiteralVersion(vertx);
+      version.set(getEntVersion(literalVersion));
+    } catch (Exception e) {
+      log.error("An error occurred while creating the metrics to expose ent version");
+      literalVersion = "error";
+      version.set(-1);
+    }
+    Gauge.builder("ent.version", version::get)
+      .tag("ent-version", literalVersion).register(registry);
+  }
+
+  private String getLiteralVersion(Vertx vertx) {
+    String entVersion = vertx.getOrCreateContext().config().getString("ent-version");
+    if(org.apache.commons.lang3.StringUtils.isEmpty(entVersion)) {
+      final LocalMap<Object, Object> localMap = vertx.sharedData().getLocalMap("server");
+      entVersion = (String)localMap.get("ent-version");
+    }
+    return StringUtils.isEmpty(entVersion) ? "na" : entVersion;
+  }
+
+  private Long getEntVersion(final String entVersion) {
+    final String cleanVersion = entVersion
+      .replaceAll("[^\\d-\\.]","")
+      .replaceAll("-", ".")
+      .replaceAll("\\.{2,}", "");
+    final String[] parts = cleanVersion.split("\\.");
+    long version = 0;
+    for(int i = 0; i < parts.length ; i++) {
+      final String part = parts[i].trim();
+      if(isNotEmpty(part)) {
+        version += (long) (Integer.parseInt(part) * Math.pow(10, VERSION_PADDING * (parts.length - (i + 1))));
+      }
+    }
+    return version;
+  }
+}