Create lookup tables metrics supplier (#24038)

* Implement lookup tables metrics supplier

* Add changelog

changelog/unreleased/pr-24038.toml

@@ -0,0 +1,5 @@
+type = "a"
+message = "Create metrics supplier for lookup tables."
+
+pulls = ["24038"]
+issues = ["Graylog2/graylog-plugin-enterprise#12226"]

graylog2-server/src/main/java/org/graylog2/lookup/db/DBLookupTableService.java

@@ -136,4 +136,13 @@ public class DBLookupTableService {
     public void forEach(Consumer<? super LookupTableDto> action) {
         collection.find().forEach(action);
     }
+
+    /**
+     * Returns the total count of lookup tables.
+     *
+     * @return total count of lookup tables
+     */
+    public long count() {
+        return collection.countDocuments();
+    }
 }

graylog2-server/src/main/java/org/graylog2/telemetry/TelemetryModule.java

@@ -22,6 +22,7 @@ import org.graylog2.telemetry.scheduler.TelemetrySubmissionPeriodical;
 import org.graylog2.telemetry.suppliers.InputsMetricsSupplier;
 import org.graylog2.telemetry.suppliers.OutputsMetricsSupplier;
 import org.graylog2.telemetry.suppliers.ShardsMetricsSupplier;
+import org.graylog2.telemetry.suppliers.LookupTablesSupplier;
 
 public class TelemetryModule extends PluginModule {
     @Override
@@ -35,5 +36,6 @@ public class TelemetryModule extends PluginModule {
         addTelemetryMetricProvider("Inputs Metrics", InputsMetricsSupplier.class);
         addTelemetryMetricProvider("Outputs Metrics", OutputsMetricsSupplier.class);
         addTelemetryMetricProvider("Shards Metrics", ShardsMetricsSupplier.class);
+        addTelemetryMetricProvider("Lookup Tables Metrics", LookupTablesSupplier.class);
     }
 }

graylog2-server/src/main/java/org/graylog2/telemetry/suppliers/LookupTablesSupplier.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2020 Graylog, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ */
+package org.graylog2.telemetry.suppliers;
+
+import jakarta.inject.Inject;
+import org.graylog2.lookup.db.DBLookupTableService;
+import org.graylog2.telemetry.scheduler.TelemetryEvent;
+import org.graylog2.telemetry.scheduler.TelemetryMetricSupplier;
+
+import java.util.Map;
+import java.util.Optional;
+
+public class LookupTablesSupplier implements TelemetryMetricSupplier {
+    private final DBLookupTableService dbLookupTableService;
+
+    @Inject
+    public LookupTablesSupplier(DBLookupTableService dbLookupTableService) {
+        this.dbLookupTableService = dbLookupTableService;
+    }
+
+    @Override
+    public Optional<TelemetryEvent> get() {
+        Map<String, Object> metrics = Map.of(
+                "lookup_table_count", dbLookupTableService.count()
+        );
+
+        return Optional.of(TelemetryEvent.of(metrics));
+    }
+}

graylog2-server/src/test/java/org/graylog2/telemetry/suppliers/LookupTablesSupplierTest.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2020 Graylog, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the Server Side Public License, version 1,
+ * as published by MongoDB, Inc.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * Server Side Public License for more details.
+ *
+ * You should have received a copy of the Server Side Public License
+ * along with this program. If not, see
+ * <http://www.mongodb.com/licensing/server-side-public-license>.
+ */
+package org.graylog2.telemetry.suppliers;
+
+import org.graylog2.lookup.db.DBLookupTableService;
+import org.graylog2.telemetry.scheduler.TelemetryEvent;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class LookupTablesSupplierTest {
+    @Mock
+    private DBLookupTableService dbLookupTableService;
+
+    @InjectMocks
+    private LookupTablesSupplier lookupTablesSupplier;
+
+    @Test
+    public void shouldReturnLookupTablesMetrics() {
+        long expectedCount = 5L;
+        when(dbLookupTableService.count()).thenReturn(expectedCount);
+
+        Optional<TelemetryEvent> metrics = lookupTablesSupplier.get();
+
+        assertTrue(metrics.isPresent());
+        assertEquals(expectedCount, metrics.get().metrics().get("lookup_table_count"));
+    }
+}