From 06cdaddd714b3310574dcacabc6e416d03646b33 Mon Sep 17 00:00:00 2001
From: Cameron Diver <cameron@balena.io>
Date: Wed, 16 Jan 2019 13:14:49 +0000
Subject: [PATCH] Send connection message when streaming local mode logs

Change-type: patch
Signed-off-by: Cameron Diver <cameron@balena.io>
---
 src/device-api/v2.ts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/device-api/v2.ts b/src/device-api/v2.ts
index bbe6762e..632bbc2e 100644
--- a/src/device-api/v2.ts
+++ b/src/device-api/v2.ts
@@ -327,6 +327,13 @@ export function createV2Api(router: Router, applications: ApplicationManager) {
 		// Get the stream, and stream it into res
 		const listenStream = backend.attachListener();
 
+		// The http connection doesn't correctly intialise until some data is sent,
+		// which means any callers waiting on the data being returned will hang
+		// until the first logs comes through. To avoid this we send an initial
+		// message
+		res.write(
+			`${JSON.stringify({ message: 'Streaming logs', isSystem: true })}\n`,
+		);
 		listenStream.pipe(res);
 	});