Quickpulse Post Request Json Bug Fix (#42144)

* fix

* changelog

* removing unnecessary imports

Author: harsimar

sdk/monitor/azure-monitor-opentelemetry-exporter/CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Breaking Changes
 
 ### Bugs Fixed
+- Fix a bug where post requests to Live Metrics returned http 400 due to malformed json.
 
 ### Other Changes
 

sdk/monitor/azure-monitor-opentelemetry-exporter/src/main/java/com/azure/monitor/opentelemetry/exporter/implementation/quickpulse/QuickPulseDataFetcher.java

@@ -6,6 +6,7 @@
 import com.azure.core.http.HttpRequest;
 import com.azure.core.util.logging.ClientLogger;
 import com.azure.monitor.opentelemetry.exporter.implementation.quickpulse.model.QuickPulseEnvelope;
+import com.azure.monitor.opentelemetry.exporter.implementation.quickpulse.model.QuickPulseMonitoringDataPoints;
 import com.azure.monitor.opentelemetry.exporter.implementation.quickpulse.model.QuickPulseMetrics;
 import com.azure.monitor.opentelemetry.exporter.implementation.utils.Strings;
 import org.slf4j.MDC;
@@ -123,9 +124,9 @@ private String buildPostEntity(QuickPulseDataCollector.FinalCounters counters) t
         postEnvelope.setTimeStamp("/Date(" + System.currentTimeMillis() + ")/");
         postEnvelope.setMetrics(addMetricsToQuickPulseEnvelope(counters));
         envelopes.add(postEnvelope);
-
+        QuickPulseMonitoringDataPoints points = new QuickPulseMonitoringDataPoints(envelopes);
         // By default '/' is not escaped in JSON, so we need to escape it manually as the backend requires it.
-        return postEnvelope.toJsonString().replace("/", "\\/");
+        return points.toJsonString().replace("/", "\\/");
     }
 
     private static List<QuickPulseMetrics>

sdk/monitor/azure-monitor-opentelemetry-exporter/src/main/java/com/azure/monitor/opentelemetry/exporter/implementation/quickpulse/model/QuickPulseMonitoringDataPoints.java

@@ -0,0 +1,20 @@
+package com.azure.monitor.opentelemetry.exporter.implementation.quickpulse.model;
+
+import com.azure.json.JsonSerializable;
+import com.azure.json.JsonWriter;
+
+import java.io.IOException;
+import java.util.List;
+
+public class QuickPulseMonitoringDataPoints implements JsonSerializable<QuickPulseEnvelope> {
+    private List<QuickPulseEnvelope> monitoringDataPoints;
+
+    public QuickPulseMonitoringDataPoints(List<QuickPulseEnvelope> monitoringDataPoints) {
+        this.monitoringDataPoints = monitoringDataPoints;
+    }
+
+    @Override
+    public JsonWriter toJson(JsonWriter jsonWriter) throws IOException {
+        return jsonWriter.writeArray(monitoringDataPoints, JsonWriter::writeJson, false);
+    }
+}