From 145bf4d7b1e823fa1fe2fe760915bc106a4dbd1b Mon Sep 17 00:00:00 2001
From: stephen <stephen@sbyrne.net>
Date: Thu, 30 Nov 2023 14:59:36 -0500
Subject: [PATCH] Connect from connect thread. Avoids stack overflow

---
 src/main/kotlin/net/eksb/obsdc/Obs.kt | 41 ++++++++++++++++-----------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/main/kotlin/net/eksb/obsdc/Obs.kt b/src/main/kotlin/net/eksb/obsdc/Obs.kt
index 76851a9..82c8a38 100644
--- a/src/main/kotlin/net/eksb/obsdc/Obs.kt
+++ b/src/main/kotlin/net/eksb/obsdc/Obs.kt
@@ -28,12 +28,14 @@ class Obs(
 	/** Queue of requests to run. */
 	private val q:BlockingQueue<Req> = LinkedBlockingQueue()
 
-	/** Backoff on errors. */
-	private val backoff = Backoff()
-
 	/** Flag to set when closed to stop queue poll loop. */
 	private val closed = AtomicBoolean(false)
 
+	/**
+	 * Flag set when we start trying to connect, unset when disconnected.
+	 * Used to determine if we should reconnect on controller error.
+	 */
+	private val connectingOrConnected = AtomicBoolean(false)
 	/**
 	 * Flag to set when connected, unset when disconnected.
 	 * Used to determine if we should reconnect on controller error.
@@ -69,9 +71,21 @@ class Obs(
 		addShutdownHook {
 			close()
 		}
-		// connect() blocks until OBS is up, so fork it.
-		thread(name="obs-init-connect", isDaemon=true, start=true) {
-			controller.connect()
+		// Thread that connects if we are not connected/connecting.
+		thread(name="obs-connect", isDaemon=true, start=true) {
+			while(!closed.get()) {
+				if (connectingOrConnected.compareAndSet(false,true)) {
+					log.debug("Not closed, not connected. Try to connect...")
+					try {
+						// Only call connect from here; if you try to call connect from [onControllerError] or [onDisconnect]
+						// eventually you will get stack overflow.
+						controller.connect()
+					} catch (e:Exception) {
+						log.warn("failed to connect: ${e.message}", e)
+					}
+				}
+				Thread.sleep(connectionTimeout.toLong() * 1000L) // in case the error was immediate
+			}
 		}
 	}
 
@@ -82,11 +96,10 @@ class Obs(
 
 	private fun onControllerError(e:ReasonThrowable) {
 		log.debug("controller error - ${e.reason}",e.throwable)
-		if (!closed.get() && !connected.get()) {
-			log.debug("connection failed")
-			backoff.backoff()
-			log.debug("reconnect after connection failed...")
-			controller.connect()
+		// If we are not connected, a controller error means that connection failed and we will not connect.
+		// If we are connected, it does not mean we are/will be disconnected.
+		if (!connected.get()) {
+			connectingOrConnected.set(false)
 		}
 	}
 	private fun onCommError(e:ReasonThrowable) {
@@ -94,12 +107,8 @@ class Obs(
 	}
 	private fun onDisconnect() {
 		log.debug("disconnected")
+		connectingOrConnected.set(false)
 		connected.set(false)
-		if (! closed.get()) {
-			backoff.backoff()
-			log.debug("reconnect after disconnected..")
-			controller.connect()
-		}
 	}
 
 	private fun onReady() {