Mask iKeys in logs (#43698)

Author: jeanbisutti

sdk/monitor/azure-monitor-opentelemetry-autoconfigure/src/main/java/com/azure/monitor/opentelemetry/autoconfigure/implementation/pipeline/TelemetryItemExporter.java

@@ -28,6 +28,7 @@
 import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
 import java.util.zip.GZIPOutputStream;
 
 import static com.azure.monitor.opentelemetry.autoconfigure.implementation.utils.AzureMonitorMsgId.TELEMETRY_ITEM_EXPORTER_ERROR;
@@ -131,18 +132,9 @@ CompletableResultCode internalSendByBatch(TelemetryItemBatchKey telemetryItemBat
     private static List<ByteBuffer> serialize(List<TelemetryItem> telemetryItems) {
         try {
             if (logger.canLogAtLevel(LogLevel.VERBOSE)) {
-                try (StringWriter debug = new StringWriter()) {
-                    for (int i = 0; i < telemetryItems.size(); i++) {
-                        JsonWriter jsonWriter = JsonProviders.createWriter(debug);
-                        telemetryItems.get(i).toJson(jsonWriter);
-                        jsonWriter.flush();
-
-                        if (i < telemetryItems.size() - 1) {
-                            debug.write('\n');
-                        }
-                    }
-                    logger.verbose("sending telemetry to ingestion service:{}{}", System.lineSeparator(), debug);
-                }
+                String json = toJson(telemetryItems);
+                String jsonWithoutIKeys = maskIKeys(telemetryItems, json);
+                logger.verbose("sending telemetry to ingestion service:{}{}", System.lineSeparator(), jsonWithoutIKeys);
             }
 
             ByteBufferOutputStream out = writeTelemetryItemsAsByteBufferOutputStream(telemetryItems);
@@ -157,6 +149,31 @@ private static List<ByteBuffer> serialize(List<TelemetryItem> telemetryItems) {
         }
     }
 
+    private static String toJson(List<TelemetryItem> telemetryItems) throws IOException {
+        try (StringWriter debug = new StringWriter()) {
+            for (int i = 0; i < telemetryItems.size(); i++) {
+                JsonWriter jsonWriter = JsonProviders.createWriter(debug);
+                TelemetryItem telemetryItem = telemetryItems.get(i);
+                telemetryItem.toJson(jsonWriter);
+                jsonWriter.flush();
+                if (i < telemetryItems.size() - 1) {
+                    debug.write('\n');
+                }
+            }
+            return debug.toString();
+        }
+    }
+
+    private static String maskIKeys(List<TelemetryItem> telemetryItems, String json) {
+        Set<String> iKeys
+            = telemetryItems.stream().map(TelemetryItem::getInstrumentationKey).collect(Collectors.toSet());
+        for (String instrumentationKey : iKeys) {
+            String maskedIKey = "*" + instrumentationKey.substring(instrumentationKey.length() - 13);
+            json = json.replace(instrumentationKey, maskedIKey);
+        }
+        return json;
+    }
+
     // gzip and add new line delimiter from a list of telemetry items to a byte buffer output stream
     private static ByteBufferOutputStream
         writeTelemetryItemsAsByteBufferOutputStream(List<TelemetryItem> telemetryItems) throws IOException {