Add option for how to batch

server/private/lib/logStreaming/providers/HttpLogDestination.ts

@@ -12,7 +12,7 @@
  */
 
 import logger from "@server/logger";
-import { LogEvent, HttpConfig } from "../types";
+import { LogEvent, HttpConfig, PayloadFormat } from "../types";
 import { LogDestinationProvider } from "./LogDestinationProvider";
 
 // ---------------------------------------------------------------------------
@@ -22,6 +22,9 @@ import { LogDestinationProvider } from "./LogDestinationProvider";
 /** Maximum time (ms) to wait for a single HTTP response. */
 const REQUEST_TIMEOUT_MS = 30_000;
 
+/** Default payload format when none is specified in the config. */
+const DEFAULT_FORMAT: PayloadFormat = "json_array";
+
 // ---------------------------------------------------------------------------
 // HttpLogDestination
 // ---------------------------------------------------------------------------
@@ -32,16 +35,31 @@ const REQUEST_TIMEOUT_MS = 30_000;
  *
  * **Payload format**
  *
- * Without a body template the payload is a JSON array, one object per event:
- * ```json
- * [
- *   { "event": "request", "timestamp": "2024-01-01T00:00:00.000Z", "data": { … } },
- *   …
- * ]
- * ```
+ * **Payload formats** (controlled by `config.format`):
  *
- * With a body template each event is rendered through the template and the
- * resulting objects are wrapped in the same outer array.  Template placeholders:
+ * - `json_array` (default) — one POST per batch, body is a JSON array:
+ *   ```json
+ *   [
+ *     { "event": "request", "timestamp": "2024-01-01T00:00:00.000Z", "data": { … } },
+ *     …
+ *   ]
+ *   ```
+ *   `Content-Type: application/json`
+ *
+ * - `ndjson` — one POST per batch, body is newline-delimited JSON (one object
+ *   per line, no outer array).  Required by Splunk HEC, Elastic/OpenSearch,
+ *   and Grafana Loki:
+ *   ```
+ *   {"event":"request","timestamp":"…","data":{…}}
+ *   {"event":"action","timestamp":"…","data":{…}}
+ *   ```
+ *   `Content-Type: application/x-ndjson`
+ *
+ * - `json_single` — one POST **per event**, body is a plain JSON object.
+ *   Use only for endpoints that cannot handle batches at all.
+ *
+ * With a body template each event is rendered through the template before
+ * serialisation.  Template placeholders:
  *   - `{{event}}`     → the LogType string ("request", "action", etc.)
  *   - `{{timestamp}}` → ISO-8601 UTC datetime string
  *   - `{{data}}`      → raw inline JSON object  (**no surrounding quotes**)
@@ -67,9 +85,41 @@ export class HttpLogDestination implements LogDestinationProvider {
     async send(events: LogEvent[]): Promise<void> {
         if (events.length === 0) return;
 
-        const headers = this.buildHeaders();
-        const payload = this.buildPayload(events);
-        const body = JSON.stringify(payload);
+        const format = this.config.format ?? DEFAULT_FORMAT;
+
+        if (format === "json_single") {
+            // One HTTP POST per event – send sequentially so a failure on one
+            // event throws and lets the manager retry the whole batch from the
+            // same cursor position.
+            for (const event of events) {
+                await this.postRequest(
+                    this.buildSingleBody(event),
+                    "application/json"
+                );
+            }
+            return;
+        }
+
+        if (format === "ndjson") {
+            const body = this.buildNdjsonBody(events);
+            await this.postRequest(body, "application/x-ndjson");
+            return;
+        }
+
+        // json_array (default)
+        const body = JSON.stringify(this.buildArrayPayload(events));
+        await this.postRequest(body, "application/json");
+    }
+
+    // -----------------------------------------------------------------------
+    // Internal HTTP sender
+    // -----------------------------------------------------------------------
+
+    private async postRequest(
+        body: string,
+        contentType: string
+    ): Promise<void> {
+        const headers = this.buildHeaders(contentType);
 
         const controller = new AbortController();
         const timeoutHandle = setTimeout(
@@ -124,9 +174,9 @@ export class HttpLogDestination implements LogDestinationProvider {
     // Header construction
     // -----------------------------------------------------------------------
 
-    private buildHeaders(): Record<string, string> {
+    private buildHeaders(contentType: string): Record<string, string> {
         const headers: Record<string, string> = {
-            "Content-Type": "application/json"
+            "Content-Type": contentType
         };
 
         // Authentication
@@ -176,24 +226,36 @@ export class HttpLogDestination implements LogDestinationProvider {
     // Payload construction
     // -----------------------------------------------------------------------
 
-    /**
-     * Build the JSON-serialisable value that will be sent as the request body.
-     *
-     * - No template  → `Array<{ event, timestamp, data }>`
-     * - With template → `Array<parsed-template-result>`
-     */
-    private buildPayload(events: LogEvent[]): unknown {
+    /** Single default event object (no surrounding array). */
+    private buildEventObject(event: LogEvent): unknown {
         if (this.config.useBodyTemplate && this.config.bodyTemplate?.trim()) {
-            return events.map((event) =>
-                this.renderTemplate(this.config.bodyTemplate!, event)
-            );
+            return this.renderTemplate(this.config.bodyTemplate!, event);
         }
-
-        return events.map((event) => ({
+        return {
             event: event.logType,
             timestamp: epochSecondsToIso(event.timestamp),
             data: event.data
-        }));
+        };
+    }
+
+    /** JSON array payload – used for `json_array` format. */
+    private buildArrayPayload(events: LogEvent[]): unknown[] {
+        return events.map((e) => this.buildEventObject(e));
+    }
+
+    /**
+     * NDJSON payload – one JSON object per line, no outer array.
+     * Each line must be a complete, valid JSON object.
+     */
+    private buildNdjsonBody(events: LogEvent[]): string {
+        return events
+            .map((e) => JSON.stringify(this.buildEventObject(e)))
+            .join("\n");
+    }
+
+    /** Single-event body – used for `json_single` format. */
+    private buildSingleBody(event: LogEvent): string {
+        return JSON.stringify(this.buildEventObject(event));
     }
 
     /**