adding scripts for invocating MQTT sensors

iot/MQTT/README.md

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+# Apache Kafka + Kafka Connect + MQTT Connector + Sensor Data
+
+This demo shows an Internet of Things (IoT) integration example using Apache Kafka + Kafka Connect + MQTT Connector + Sensor Data.
+
+This project does not include any source code as Kafka Connect allows integration with data sources and sinks just with configuration. 
+
+
+### Requirements
+- Java 8
+- [Confluent Platform 5.0+](https://www.confluent.io/download/) (Confluent Enterprise if you want to use the Confluent MQTT Proxy, Confluent Open Source if you just want to run the KSQL UDF and send data via kafkacat instead of MQTT)
+- MQTT Client and Broker (this demo uses [Mosquitto](https://mosquitto.org/download/))
+- [Confluent MQTT Connector](https://www.confluent.io/connector/kafka-connect-mqtt/) (a Kafka Connect based connector to send and receive MQTT messages) - Very easy installation via Confluent Hub, just one command:
+
+                confluent-hub install confluentinc/kafka-connect-mqtt:1.0.0-preview
+- Optional: [MQTT.fx](https://mqttfx.jensd.de/) (a nice, simple UI to test MQTT pub/sub; not required - just makes life more comfortable)
+
+The code is developed and tested on Mac.
+
+
+
+
+
+

iot/MQTT/sensor_generator.sh

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+#! /bin/bash
+
+#Log levels
+OFF=0
+FATAL=100
+ERROR=200
+WARN=300
+INFO=400
+DEBUG=500
+
+#Sensor value range
+MINVAL=2
+MAXVAL=8
+DECVAL=2
+EVENTID=99999
+
+#Measurement array
+ASIZE=210
+ADELIM="#"
+initVal=""
+msgSize=0
+msgArr=""
+arrLen=0
+msgNr=0
+
+#MQTT Client command
+PUBEXE="mosquitto_pub"
+HOST="0.0.0.0" 
+PORT=1883
+TOPIC="temperature"
+QOS=2
+
+#Set log level for the script
+LOGLEVEL=$INFO
+
+log()
+{ # This function will log the input message to STDOUT if the log level for the message is lower or equal to the log level set for the script
+	local logMessage=$1
+	local msgLevel=$2
+
+	if [ $LOGLEVEL -ge $msgLevel ]
+	then
+		echo -e $logMessage
+	fi
+}
+
+initialVal()
+{ # This function initialises a sensor value for the signal we want to generate
+
+  local initBase=-1
+  local initFract=0
+  local decMod=$((10**$DECVAL))
+  log "Modulus divisor value for decimal generation is: $decMod" $DEBUG
+
+  until [ $initBase -ge $MINVAL ] && [ $initBase -lt $MAXVAL ]
+  do
+    initBase=$((RANDOM % $MAXVAL))
+    log "Ïnitial generated sensor base value is: $initBase" $DEBUG
+  done
+
+  initFract=$(($RANDOM % $decMod))
+
+  # Prepend 0's for fractions with a shorter length then the nr of defined decimails0
+  while [ ${#initFract} -lt $DECVAL ]
+  do
+    initFract=0${initFract}
+    log "Random generated number was smaller than 100, appending it with zeros. Current number value is $initFract" $DEBUG
+  done
+
+  initVal="${initBase}.${initFract}"
+  log "Ïnitial generated sensor value is: $initVal" $DEBUG
+  return 0
+}
+
+genInterval()
+{ # This function will generate an increasing or decreasing interval of sensor reading values, based on its input parameters of startReading, intervalSize and intervalDirection
+
+  local sensReading="`echo $1 | cut -f 1 -d '.'``echo $1 | cut -f 2 -d '.'`"
+  log "Last sensor reading value: $sensReading" $DEBUG
+  local intSize=$2
+  log "Interval size: $intSize" $DEBUG
+  local intDirection=$3
+  local incrDiv=0
+  local readIncr=-1
+  local newReading
+  local intArr=""
+  local i=0
+
+  while [ $i -lt $intSize ]
+  do
+    # Generate an reading value increment size (choice between 1/100th or 1/10th multple)
+    incrDiv=$((10**$(($(($RANDOM % 2))+1))))
+    log "Increment divisor: $incrDiv" $DEBUG
+
+    # Generate reading value increment
+    readIncr=$(($RANDOM % $incrDiv))
+
+    if [ $intDirection -eq 0 ]
+    then 
+      readIncr=$(($readIncr * -1))
+    fi    
+    log "Reading increment is : $readIncr" $DEBUG
+
+    #Calculate new reading
+    sensReading=$(($sensReading + $readIncr))
+    log "New generated reading number in interval is: $sensReading" $DEBUG
+
+    newReading="`echo $sensReading | cut -c 1`.`echo $sensReading|cut -c 2-3`"
+    log "New generated reading value in interval is: $newReading" $DEBUG
+
+    # Swap the interval direction in case we've crossed a boundary value
+    if [ $intDirection -eq 0 ] && [ $sensReading -le $(($MINVAL * 100)) ]
+    then
+      intDirection=1
+    elif [ $intDirection -eq 1 ] && [ $sensReading -ge $(($MAXVAL * 100)) ]
+    then
+      intDirection=0
+    fi
+
+    intArr="${intArr}${newReading}${ADELIM} "
+    log "Current sensor readings interval array: $intArr" $DEBUG
+    i=$(($i+1))
+  done
+  msgArr=${msgArr}${intArr}
+  msgSize=$(($msgSize + $intSize))
+  return 0
+}
+
+
+randomTemp()
+{ # This function will generate a random temperature value between 0 and 10 and two decimals precision
+
+ local temp=""
+ # Generate random number	
+ local rNum=$RANDOM
+ log "Random generated number : $rNum" $DEBUG
+
+  # Append 0's for random numbers smaller than 100
+  while [ ${#rNum} -lt 3 ]
+  do 
+    rNum=${rNum}0
+    log "Random generated number was smaller than 100, appending it with zeros. Current number value is $rNum" $DEBUG
+  done
+
+  # Construct random temperature value from first 3 digits of random number
+  temp="`echo $rNum|cut -c 1`.`echo $rNum|cut -c 2-3`"
+  log "Random generated temperature value of $temp" $DEBUG
+
+  return $temp
+}
+
+# We are not in the main program. Let's first initialize a first measurement value
+initialVal
+
+if [ $? -eq 0 ]
+then 
+  log "initialVal function returned initial sensor value : $initVal" $DEBUG
+
+  # Now we will start the endless loop to generate sensorvalues in ranges
+  while true;
+  do
+    if [ $msgSize -eq 0 ]
+    then
+      #initialise a new message array
+      msgNr=$(($msgNr + 1))
+      msgArr="${EVENTID},"
+    fi
+
+    # Now lets generate sensor value ranges that increase or decrease from the current sensor value
+    rangeLength=$(($(($RANDOM % 10))+1)) # a value between 1 and 10
+    if [ $ASIZE -lt $(($msgSize + $rangeLength)) ]
+    then
+	    rangeLength=$(($ASIZE - $msgSize))
+    fi
+    log "Length for the interval is: $rangeLength" $DEBUG
+
+    rangeDir=$((RANDOM % 2)) # 0 is decreasing interval and 1 is an increasing interval
+    log "Direction for the interval is: $rangeDir" $DEBUG
+
+    genInterval $initVal $rangeLength $rangeDir
+
+    if [ $? -eq 0 ]
+    then
+      arrLen=${#msgArr}
+      log "Current measurements array for next message to sent is: $msgArr" $DEBUG
+      if [ $msgSize -eq $ASIZE ]
+      then 
+	# We need to prepare the message for sending, by removing the last two characters (delimter)
+	msgArr=`echo $msgArr | cut -c 1-$(($arrLen - 2))`
+    # log "${PUBEXE} -h ${HOST} -p ${PORT} -t ${TOPIC} -q ${QOS} -m \"${msgArr}\"" $DEBUG
+    $(${PUBEXE} -h ${HOST} -p ${PORT} -t ${TOPIC} -q ${QOS} -m "${msgArr}")
+
+	if [ $? -eq 0 ] 
+        then 
+          log "New message published, nr: $msgNr" $INFO
+	  msgSize=0
+
+	  log "Current message measurement array has a length of : $arrLen" $DEBUG
+       	  initVal=`echo $msgArr | cut -c $(($arrLen - 5))-$(($arrLen))`
+   	  log "New start measurement value for next message is : $initVal" $DEBUG
+        fi
+      else
+        # We need take the last measurement from the interval and set it as the initialisation value for the next interval
+	log "Current message measurement array has a length of : $arrLen" $DEBUG
+	initVal=`echo $msgArr | cut -c $(($arrLen - 5))-$(($arrLen - 2))`
+	log "New start measurement value for next interval is : $initVal" $DEBUG
+      fi
+    fi
+  done
+fi