使用 AWS Lambda 和 AWS Greengrass 在边缘站点进行协议转换

sudo apt-get updatesudo apt-get install python-devsudo apt-get install python-pipsudo pip install pymodbussudo pip install pycryptosudo pip install pyasn1

#
# Copyright 2010-2017 Amazon.com, Inc. or its affiliates.保留所有权利。#
# ModbusSlaveServer.py# Runs a modbus slave device in memory for testing purposes.# This AWS Lambda function allocates registers for the modbus tcp slave and starts# the server.If an exception occurs, it will wait 5 seconds and try again.# Since the function is long-lived it will run forever when deployed to a# Greengrass core. The handler will NOT be invoked in our example since# the we are executing an infinite loop.
import timeimport loggingimport sys#import pymodbus libraries for the serverfrom pymodbus.server.sync import StartTcpServerfrom pymodbus.datastore import ModbusSequentialDataBlockfrom pymodbus.datastore import ModbusSlaveContext, ModbusServerContext
# instantiate logger which will log any exceptions to Cloudwatch or Greengrass# local logslogger = logging.getLogger(__name__)logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
while True:try:#create registy for modbus serverstore = ModbusSlaveContext(di = ModbusSequentialDataBlock(0, [17]*100),co = ModbusSequentialDataBlock(0, [17]*100),hr = ModbusSequentialDataBlock(0, [17]*100),ir = ModbusSequentialDataBlock(0, [17]*100))context = ModbusServerContext(slaves=store, single=True)
# change default port of modbus from 502 to 5020 as it requires# root permissions below 1024StartTcpServer(context, address=("localhost", 5020))except Exception, e:logging.info("Error: {0}".format(str(e)))time.sleep(5)
# this function is never called as it will be configured as long-lived.def lambda_handler(event, context):return 'Hello' 

## Copyright 2010-2017 Amazon.com, Inc. or its affiliates.保留所有权利。#
# ModbusSlaveSim.py# This is a simulator script that connects to a modbus slave device and# writes the CPU temperature for the raspberry pi device to a modbus register.# If an exception occurs, it will wait 5 seconds and try again.# Since the function is long-lived it will run forever when deployed to a# Greengrass core. The handler will NOT be invoked in our example since# we are executing an infinite loop.
import timeimport loggingimport sysimport os# import pymodbus libraries for the simulator clientfrom pymodbus.client.sync import ModbusTcpClient as ModbusClientfrom pymodbus.payload import BinaryPayloadDecoderfrom pymodbus.payload import BinaryPayloadBuilderfrom pymodbus.constants import Endianfrom pymodbus.compat import iteritems
# Default port for modbus slave is typically 502.Using 5020 for simulation to# avoid root permissions.client = ModbusClient('127.0.0.1', port=5020)
# instantiate logger which will log any exceptions to Cloudwatch or Greengrass# local logslogger = logging.getLogger(__name__)logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
# returns the cpu temperature from the raspberry pi devicedef get_temp():f = open("/sys/class/thermal/thermal_zone0/temp")CPUTemp = f.read()f.close()return float(CPUTemp)/1000.0
# in an infinite loop, this procedure will poll the cpu temperature and write# it to a local modbus slave device.def poll_temp():while True:try:client.connect()builder = BinaryPayloadBuilder(endian=Endian.Big)builder.add_32bit_float(get_temp())payload = builder.build()address = 0rq = client.write_registers(address, payload, skip_encode=True, unit=1)
except Exception, e:logging.info("Error: {0}".format(str(3)))time.sleep(5)
# executing polling on startup.poll_temp()
# this function is never called as it will be configured as long-lived.def lambda_handler(event, context):return 'Hello'

## Copyright 2010-2017 Amazon.com, Inc. or its affiliates.保留所有权利。#
# ModbusToAWSIoT.py# This is an example script that connects to a modbus slave device to read# a temperature value and publish to an MQTT Topic in AWS IoT every 5 seconds.# If an exception occurs, it will wait 5 seconds and try again.# Since the function is long-lived it will run forever when deployed to a# Greengrass core. The handler will NOT be invoked in our example since# we are executing an infinite loop.
import greengrasssdkimport platformfrom threading import Timerimport timeimport loggingimport sysimport json# import pymodbus libraries for the modbus clientfrom pymodbus.client.sync import ModbusTcpClient as ModbusClientfrom pymodbus.payload import BinaryPayloadDecoderfrom pymodbus.payload import BinaryPayloadBuilderfrom pymodbus.constants import Endianfrom pymodbus.compat import iteritems
# Instantiate the client for your modbus slave device.In this example we are# using the local IP address where a simulator exists.Change this to your# desired IP.In addition, the typical default port for Modbus TCP is 502.For# this example, 5020 was used.mbclient = ModbusClient('127.0.0.1', port=5020)
# Default port for modbus slave is typically 502.Using 5020 for simulation to# avoid root permissions.logger = logging.getLogger(__name__)logging.basicConfig(stream=sys.stdout, level=logging.DEBUG)
# Creating a greengrass core sdk clientclient = greengrasssdk.client('iot-data')
# in an infinite loop, this procedure will poll the bearing temperature from a# modbus slave device (simulator) and publish the value to AWS IoT via MQTT.def poll_temp():while True:try:# connect to modbus slave devicembclient.connect()# set the address and number of bytes that will be read on the modbus deviceaddress = 0x00count = 8# read the holding register value for the temperaturerr = mbclient.read_holding_registers(address, count, unit=1)# decode results as a 32 bit floatdecoder = BinaryPayloadDecoder.fromRegisters(rr.registers, endian=Endian.Big)decoded = {'float': decoder.decode_32bit_float()}# publish results to topic in AWS IoTfor name, value in iteritems(decoded):client.publish(topic='dt/controller/extruder/plc1/rtd', payload=json.dumps({ 'Temp': value}))except Exception, e:logging.info("Error: {0}".format(str(e)))
time.sleep(5)
poll_temp()
# This is a dummy handler and will not be invoked# Instead the code above will be executed in an infinite loop for our exampledef function_handler(event, context):return