Hi,
I have created a B4J non-UI app that will receive a UDP message and then send the message by MQTT.
Everything had been working fine, and then all of a sudden I am noticing a strange thing happening.
As the UDP message arrives, I am then sending it by MQTT. If the message contains a value, then I want to send it to a second MQTT topic.
If I make it so that it only sends the message to a single MQTT topic, then it works fine. Soon as I add the second MQTT topic then I am noticing all MQTT messages are delayed in being sent for a few minutes and evenly stops all together.
I'm not sure if this is due to too many incoming UDP messages or some other bottleneck. I also don't know how to resolve this issue.
I am using Mosquitto as the MQTT broker.
The MQTT broker and B4J is on the same VPS server running on Linux Ubuntu.
Here is how I am doing It:
The above code used to work, but now it runs really slow and the it will crash my B4J app.
If I remove (or comment out) the following, then the code works fine. The first MQTT message is sent in almost realtime.
If I add the above line back in again, the first MQTT message is delayed by many minutes before my B4J crashes.
If I run the code as above (so it sends the 2 MQTT messages) and only one UDP message being received to the B4J app then it works fine and both MQTT topics are sent fine.
Soon as many messages are received then it crashes.
To work out how many MQTT messages are being sent, I added a Global int in the main module and commented out the MQTT being sent.
The first MQTT message is sent 450 messages per second (on average).
The second MQTT message is sent 320 messages per second (on average).
I am trying to learn and work out why it is causing this issue when I try and send the second MQTT message.
I have created a B4J non-UI app that will receive a UDP message and then send the message by MQTT.
Everything had been working fine, and then all of a sudden I am noticing a strange thing happening.
As the UDP message arrives, I am then sending it by MQTT. If the message contains a value, then I want to send it to a second MQTT topic.
If I make it so that it only sends the message to a single MQTT topic, then it works fine. Soon as I add the second MQTT topic then I am noticing all MQTT messages are delayed in being sent for a few minutes and evenly stops all together.
I'm not sure if this is due to too many incoming UDP messages or some other bottleneck. I also don't know how to resolve this issue.
I am using Mosquitto as the MQTT broker.
The MQTT broker and B4J is on the same VPS server running on Linux Ubuntu.
Here is how I am doing It:
Main Module:
'Non-UI application (console / server application)
#Region Project Attributes
#CommandLineArgs:
#MergeLibraries: True
#End Region
Sub Process_Globals
Private working As Boolean = True
Public mqtt As MqttClient 'jMQTT Lib v1.25
Private username As String = "Mqtt_username_here"
Public MQTT_password As String = $"My_MQTT_Password_here"$
Private MQTT_Protocol As String = "tcp" ' using TCP
Private MQTT_Server As String = "localhost"
Private MQTT_Port As String = "1883"
Public Server_ID As String = "server1"
Type MQTTMSG (message As String)
Dim serializator As B4XSerializator ' jRandomAccessFile Lib v2.34
Dim su As StringUtils ' jStringUtils Lib 1.03
End Sub
Sub AppStart (Args() As String)
MQTTInitialize
StartMessageLoop
End Sub
Sub MQTTInitialize
working = True
Do While working
If mqtt.IsInitialized Then mqtt.Close
mqtt.Initialize("mqtt", MQTT_Protocol & "://" & MQTT_Server & ":" & MQTT_Port, "cloud_1_" & Rnd(0, 999999999))
Dim mo As MqttConnectOptions 'jMQTT Lib v1.25
mo.Initialize(username, MQTT_password)
Log("MQTT Trying to connect")
mqtt.Connect2(mo)
Wait For Mqtt_Connected (Success As Boolean)
If Success Then
Log("MQTT Connected")
incomingUDP.Initialize ' Start listening to UDP messages
Do While working And mqtt.Connected
mqtt.Publish2("Cloud_1_Ping", Array As Byte(0), 1, False)
Sleep(5000)
Loop
Log("MQTT Disconnected")
Else
Log("MQTT Error connecting.")
End If
Sleep(5000)
Loop
End Sub
Sub SendMessageMQTT(Topic As String, msg As String)
Try
If mqtt.Connected = False Then
Log("MQTTClient is not connected.")
Return
Else
mqtt.Publish2(Topic, CreateMessage(msg), 0,False)
End If
Catch
Log("error: SendMessageMQTT")
Log(LastException.Message)
End Try
End Sub
public Sub CreateMessage(msg As String) As Byte()
Dim m As MQTTMSG
m.Initialize
m.message = EncryptText(msg)
Return serializator.ConvertObjectToBytes(m)
End Sub
Public Sub EncryptText(text As String) As String
Dim c As B4XCipher 'B4XEncryption Lib v1.00
Return su.EncodeBase64(c.Encrypt(text.GetBytes("utf8"), "MySecurePasswordHere"))
End Sub
incomingUDP:
Sub Process_Globals
Dim Port As String = "5422"
Dim EventSockUDP As UDPSocket ' jNetwork Lib v1.20
End Sub
Sub Initialize
EventSockUDP.Initialize("UDP",Port,600)
End Sub
Sub UDP_PacketArrived (Packet As UDPPacket)
Try
' incomining messages will look like this: xxxxxxxx//0//xxxxx.....xxxxx
Dim msg As String ' This will hold the incoming message
msg = BytesToString(Packet.Data, Packet.Offset, Packet.Length, "Windows-1252")
Dim msg_string() As String = Regex.Split("//",msg)
Try
If msg_string.Length < 3 Then
Log("Invalid Message: " & msg)
Log("Length is too short.. Ignore Message")
Log("IP: " & Packet.Host & ", Port: " & Packet.Port)
Return
End If
Catch
Log(LastException.Message)
End Try
' 0 1 2
' xxxxxxxx//0//xxxxx.....xxxxx
' ^
If msg_string(1) = "1" Then
' Ignore any that are set to 1
Return
End If
' 0 1 2
' xxxxxxxx//0//xxxxx.....xxxxx
' ^
msg = msg_string(2)
' If the message is nothing then ignore message
If msg = Null Then Return
If msg = "" Then Return
' remove Carriage Return Line Feed
msg = msg.Replace(Chr(10),"")
msg = msg.Replace(Chr(13),"")
' Send MQTT Message
' msg_string(0) = Topic
' msg_string(0)//msg = Message to send
Main.SendMessageMQTT(msg_string(0),msg_string(0) & "//" & msg)
' If the message (MSG) 3 and 4 value is "AA" Or "BB" then send a second MQTT message to a different MQTT Topic
If msg.SubString2(2,4) = "AA" Or msg.SubString2(2,4) = "AB" Then
Main.SendMessageMQTT("FCM",msg_string(0) & "//" & msg)
End If
Catch
Log(LastException.Message)
Log("IP: " & Packet.Host & ", Port: " & Packet.Port)
End Try
End SubThe above code used to work, but now it runs really slow and the it will crash my B4J app.
If I remove (or comment out) the following, then the code works fine. The first MQTT message is sent in almost realtime.
B4X:
Main.SendMessageMQTT("FCM",msg_string(0) & "//" & msg)If I add the above line back in again, the first MQTT message is delayed by many minutes before my B4J crashes.
If I run the code as above (so it sends the 2 MQTT messages) and only one UDP message being received to the B4J app then it works fine and both MQTT topics are sent fine.
Soon as many messages are received then it crashes.
To work out how many MQTT messages are being sent, I added a Global int in the main module and commented out the MQTT being sent.
The first MQTT message is sent 450 messages per second (on average).
The second MQTT message is sent 320 messages per second (on average).
I am trying to learn and work out why it is causing this issue when I try and send the second MQTT message.
