doug.iotdemo.lambda.sensor.SensorLambda.java Source code

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Here is the source code for doug.iotdemo.lambda.sensor.SensorLambda.java

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/*******************************************************************************
 * Copyright (c) 2016 QNX Software Systems and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package doug.iotdemo.lambda.sensor;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.paho.client.mqttv3.MqttException;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.model.AttributeAction;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.AttributeValueUpdate;
import com.amazonaws.services.dynamodbv2.model.GetItemRequest;
import com.amazonaws.services.dynamodbv2.model.GetItemResult;
import com.amazonaws.services.dynamodbv2.model.UpdateItemRequest;
import com.amazonaws.services.lambda.runtime.Context;
import com.amazonaws.services.lambda.runtime.RequestStreamHandler;
import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.AmazonSQSClient;
import com.amazonaws.services.sqs.model.SendMessageRequest;
import com.google.gson.Gson;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

import doug.iotdemo.common.AmazonUtils;
import doug.iotdemo.common.MQTTUtils;

public class SensorLambda implements RequestStreamHandler {

    private AmazonDynamoDB db = new AmazonDynamoDBClient();
    private String sensorTableName = AmazonUtils.getSensorTableName();

    @Override
    public void handleRequest(InputStream input, OutputStream output, Context context) throws IOException {
        Path certPath = Files.createTempFile("cert", ".jks");
        InputStream certIn = getClass().getResourceAsStream("/lambda.jks");
        Files.copy(certIn, certPath, StandardCopyOption.REPLACE_EXISTING);
        System.setProperty("javax.net.ssl.keyStore", certPath.toString());
        System.setProperty("javax.net.ssl.keyStorePassword", "password");

        JsonObject request = new JsonParser().parse(new InputStreamReader(input)).getAsJsonObject();
        System.out.println("Request: " + request);

        if (!request.has("sensor")) {
            System.out.println("No sensor id");
            return;
        }

        if (request.has("init")) {
            handleInitMessage(request);
        }

        if (request.has("state")) {
            handleStateChange(request);
        }

        if (request.has("time")) {
            handleTime(request);
        }

        Files.deleteIfExists(certPath);
    }

    /*
     * Send down the current threshold value.
     */
    private void handleInitMessage(JsonObject request) throws IOException {
        try {
            long thresh = 20000; // default

            String sensor = request.get("sensor").getAsString();
            GetItemRequest getRequest = new GetItemRequest().withTableName(sensorTableName).addKeyEntry("sensor",
                    new AttributeValue().withS(sensor));
            GetItemResult getResult = db.getItem(getRequest);
            Map<String, AttributeValue> sensorItem = getResult.getItem();
            if (sensorItem != null && sensorItem.containsKey("time")) {
                long time = Long.parseLong(sensorItem.get("time").getN());
                long count = Long.parseLong(sensorItem.get("count").getN());
                thresh = time / count;
            }

            new MQTTUtils().sendThreshold(sensor, thresh);
        } catch (MqttException e) {
            throw new IOException(e);
        }
    }

    /*
     * Update the sensor's state in the db.
     */
    private void handleStateChange(JsonObject request) throws IOException {
        UpdateItemRequest updateRequest = new UpdateItemRequest().withTableName(sensorTableName)
                .addKeyEntry("sensor", new AttributeValue().withS(request.get("sensor").getAsString()))
                .addAttributeUpdatesEntry("state",
                        new AttributeValueUpdate(
                                new AttributeValue().withN(Integer.toString(request.get("state").getAsInt())),
                                AttributeAction.PUT));
        db.updateItem(updateRequest);
        System.out.println("Sensor table updated");
    }

    /*
     * Store the new time value in Dynamo and send SQS to analyzer
     */
    private void handleTime(JsonObject request) throws IOException {
        Map<String, AttributeValue> item = new HashMap<>();
        item.put("sensor", new AttributeValue().withS(request.get("sensor").getAsString()));
        item.put("timestamp", new AttributeValue().withN(Long.toString(System.currentTimeMillis())));
        item.put("time", new AttributeValue().withN(Integer.toString(request.get("time").getAsInt())));
        db.putItem(AmazonUtils.getTimeTableName(), item);
        System.out.println("Item writen to TimeTable");

        AmazonSQS sqs = new AmazonSQSClient();
        String url = AmazonUtils.getTimeQueueURL();
        sqs.sendMessage(new SendMessageRequest(url, new Gson().toJson(request)));
        System.out.println("SQS Message sent to " + url);
    }

}