Fix missing parameter storage metrics (#252)

Fixed open telemetry gauge value provider

Author: Rentacookie

.changeset/small-clouds-collect.md

@@ -0,0 +1,6 @@
+---
+'@powersync/service-module-mongodb-storage': patch
+'@powersync/service-core': patch
+---
+
+Fixed opentelemetry observable gauge value provider ignoring 0 values

modules/module-mongodb-storage/src/storage/MongoBucketStorage.ts

@@ -306,7 +306,7 @@ export class MongoBucketStorage
   }
 
   async getStorageMetrics(): Promise<storage.StorageMetrics> {
-    const ignoreNotExiting = (e: unknown) => {
+    const ignoreNotExisting = (e: unknown) => {
       if (lib_mongo.isMongoServerError(e) && e.codeName == 'NamespaceNotFound') {
         // Collection doesn't exist - return 0
         return [{ storageStats: { size: 0 } }];
@@ -333,7 +333,7 @@ export class MongoBucketStorage
         }
       ])
       .toArray()
-      .catch(ignoreNotExiting);
+      .catch(ignoreNotExisting);
 
     const parameters_aggregate = await this.db.bucket_parameters
       .aggregate([
@@ -344,7 +344,7 @@ export class MongoBucketStorage
         }
       ])
       .toArray()
-      .catch(ignoreNotExiting);
+      .catch(ignoreNotExisting);
 
     const replication_aggregate = await this.db.current_data
       .aggregate([
@@ -355,7 +355,7 @@ export class MongoBucketStorage
         }
       ])
       .toArray()
-      .catch(ignoreNotExiting);
+      .catch(ignoreNotExisting);
 
     return {
       operations_size_bytes: Number(operations_aggregate[0].storageStats.size),

packages/service-core/src/metrics/open-telemetry/OpenTelemetryMetricsFactory.ts

@@ -35,7 +35,7 @@ export class OpenTelemetryMetricsFactory implements MetricsFactory {
         gauge.addCallback(async (result) => {
           const value = await valueProvider();
 
-          if (value) {
+          if (value != undefined) {
             result.observe(value);
           }
         });

packages/service-core/src/storage/storage-metrics.ts

@@ -34,7 +34,7 @@ export function initializeCoreStorageMetrics(engine: MetricsEngine, storage: Buc
   let cacheTimestamp = 0;
 
   const getMetrics = () => {
-    if (cachedRequest == null || Date.now() - cacheTimestamp > MINIMUM_INTERVAL) {
+    if (!cachedRequest || Date.now() - cacheTimestamp > MINIMUM_INTERVAL) {
       cachedRequest = storage.getStorageMetrics().catch((e) => {
         logger.error(`Failed to get storage metrics`, e);
         return null;