From e5654d807f84faad8c6e87225d65494f0172608a Mon Sep 17 00:00:00 2001
From: Reuben Rodrigues <admin@reubenrodrigues.com>
Date: Tue, 4 May 2021 13:36:17 +0000
Subject: [PATCH] fixup! core: reuse remote transcoder for stream

---
 core/orch_test.go    | 66 +++++++++++++++++++++++++-------------------
 core/orchestrator.go |  5 ++++
 2 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/core/orch_test.go b/core/orch_test.go
index bb8115ec8f..67fe910c9e 100644
--- a/core/orch_test.go
+++ b/core/orch_test.go
@@ -9,6 +9,7 @@ import (
 	"math/big"
 	"math/rand"
 	"os"
+	"strconv"
 	"sync"
 	"testing"
 	"time"
@@ -388,36 +389,45 @@ func TestCompleteStreamSession(t *testing.T) {
 }
 
 func TestRemoveFromRemoteTranscoders(t *testing.T) {
-	m := NewRemoteTranscoderManager()
-	strm := &StubTranscoderServer{manager: m}
-	strm2 := &StubTranscoderServer{manager: m}
-
-	// sanity check that transcoder is not in liveTranscoders or remoteTranscoders
+	remoteTranscoderList := []*RemoteTranscoder{}
 	assert := assert.New(t)
-	assert.Nil(m.liveTranscoders[strm])
-	assert.Empty(m.remoteTranscoders)
-
-	// register transcoders, which adds transcoder to liveTranscoders and remoteTranscoders
-	go func() { m.Manage(strm, 1) }()
-	time.Sleep(1 * time.Millisecond) // allow time for first stream to register
-	go func() { m.Manage(strm2, 1) }()
-	time.Sleep(1 * time.Millisecond) // allow time for second stream to register
-
-	// assert two transcoders added
-	assert.Len(m.remoteTranscoders, 2)
-	t1 := m.liveTranscoders[strm]
-	t2 := m.liveTranscoders[strm2]
-
-	assert.Equal(m.remoteTranscoders[0], t1)
-	assert.Equal(m.remoteTranscoders[1], t2)
-
-	// Remove transcoders and assert size reduces
-	m.remoteTranscoders = removeFromRemoteTranscoders(t1, m.remoteTranscoders)
-	assert.Equal(m.remoteTranscoders[0], t2)
-	assert.Len(m.remoteTranscoders, 1)
 
-	m.remoteTranscoders = removeFromRemoteTranscoders(t2, m.remoteTranscoders)
-	assert.Len(m.remoteTranscoders, 0)
+	// Create 4 tanscoders
+	tr := make([]*RemoteTranscoder, 4)
+	for i := 0; i < 4; i++ {
+		tr[i] = &RemoteTranscoder{addr: "testAddress" + strconv.Itoa(i)}
+	}
+
+	// Add to list
+	remoteTranscoderList = append(remoteTranscoderList, tr...)
+	assert.Len(remoteTranscoderList, 4)
+
+	// Remove transcoder froms head of the list
+	remoteTranscoderList = removeFromRemoteTranscoders(tr[0], remoteTranscoderList)
+	assert.Equal(remoteTranscoderList[0], tr[1])
+	assert.Equal(remoteTranscoderList[1], tr[2])
+	assert.Equal(remoteTranscoderList[2], tr[3])
+	assert.Len(remoteTranscoderList, 3)
+
+	// Remove transcoder from the middle of the list
+	remoteTranscoderList = removeFromRemoteTranscoders(tr[3], remoteTranscoderList)
+	assert.Equal(remoteTranscoderList[0], tr[1])
+	assert.Equal(remoteTranscoderList[1], tr[2])
+	assert.Len(remoteTranscoderList, 2)
+
+	// Remove transcoder from the end of the list
+	remoteTranscoderList = removeFromRemoteTranscoders(tr[2], remoteTranscoderList)
+	assert.Equal(remoteTranscoderList[0], tr[1])
+	assert.Len(remoteTranscoderList, 1)
+
+	// Remove the last transcoder
+	remoteTranscoderList = removeFromRemoteTranscoders(tr[1], remoteTranscoderList)
+	assert.Len(remoteTranscoderList, 0)
+
+	// Remove a transcoder when list is empty
+	remoteTranscoderList = removeFromRemoteTranscoders(tr[1], remoteTranscoderList)
+	emptyTList := []*RemoteTranscoder{}
+	assert.Equal(remoteTranscoderList, emptyTList)
 }
 
 func TestTranscoderManagerTranscoding(t *testing.T) {
diff --git a/core/orchestrator.go b/core/orchestrator.go
index 8d68af24e4..ad475e4811 100644
--- a/core/orchestrator.go
+++ b/core/orchestrator.go
@@ -860,6 +860,11 @@ func (rtm *RemoteTranscoderManager) Manage(stream net.Transcoder_RegisterTransco
 }
 
 func removeFromRemoteTranscoders(rt *RemoteTranscoder, remoteTranscoders []*RemoteTranscoder) []*RemoteTranscoder {
+	if len(remoteTranscoders) == 0 {
+		// No transocerds to remove, return
+		return remoteTranscoders
+	}
+
 	lastIndex := len(remoteTranscoders) - 1
 	last := remoteTranscoders[lastIndex]
 	if rt == last {