Google Home Guide

Learn to make a Goole action using Grails

Authors: Ryan Vanderwerf, Sergio del Amo

Grails Version: 3.3.0

1 Grails Training

Grails Training - Developed and delivered by the folks who created and actively maintain the Grails framework!.

2 Getting Started

In this guide you are going to learn how to create a Grails application to host a Google Action for your Google Home device to interact with. We will build, deploy, and set up everything necessary to facilitate this on Google App Engine Flexible and Google APIs.

We will be using the early access unofficial Java SDK to build actions. This is because the only official SDK is built with node.

2.1 What you will need

Some time on your hands
A decent text editor or IDE
A Google account
A Google Cloud account
curl command to help debugging

2.2 How to complete the guide

To get started do the following:

Download and unzip the source

Clone the Git repository:
git clone https://github.com/grails-guides/grails-google-home.git

The Grails guides repositories contain two folders:

initial Initial project. Often a simple Grails app with some additional code to give you a head-start.
complete A completed example. It is the result of working through the steps presented by the guide and applying those changes to the initial folder.

To complete the guide, go to the initial folder

cd into grails-guides/grails-google-home/initial

and follow the instructions in the next sections.

You can go right to the completed example if you cd into grails-guides/grails-google-home/complete

The initial project is a Grails Application built with the web profile where we removed the asset-pipeline and hibernate depenencies.

Although you can go right to the completed example, in order to deploy the app you would need to complete several configuration steps Google Cloud Settings.

You will need to edit the file src/main/resources/action.json to point to your Google App Engine Flexible deployment.

3 Google Cloud Settings

This guide uses paid services; you may need to enable Billing in Google Cloud to complete some steps in this guide.

3.1 Create a Google Cloud Project

Signup for Google Cloud Platform and create a new project:

Install Cloud SDK for your operating system.

After you have installed the SDK, run the init command in your terminal:

$ gcloud init

It will prompt you to select the Google account and the project which you want to use.

3.2 Install gactions CLI

We will use gactions CLI to test our app.

Go to gactions CLI and download it:

Make the gactions binary executable (chmod +x on linux and OSX).

After you have installed gactions, run the init command in your terminal:

$ gactions init --force

Other commands you can run: preview, update, deploy, test, and list.

3.3 Configure Google Actions

Enable Google Actions API

Go to Google API Manager Console and enable Google Actions API.

Import your Project to the Google Actions Console

Go to the new Google Actions Console and import the project your previoulsy created:

Configure your project ID in `action.json`

action.json is a metadata file which we use to inform the Google Cloud Actions Console about the actions supported by our application.

Here you can also control:

sample queries to help google understand which action to call
intent to call

src/main/resources/action.json

{
  "actions": [
    {
      "description": "Default Welcome Intent",
      "name": "MAIN",
      "fulfillment": {
        "conversationName": "color-finder-echo"
      },
      "intent": {
        "name": "actions.intent.MAIN"
      }

    },
    {
      "description": "Deep link that finds brighter colors",
      "name":"color.intent",
      "fulfillment": {
        "conversationName": "color.intent"
      },
      "intent": {
        "name": "color.intent",
        "parameters": [{
          "name": "color",
          "type": "SchemaOrg_Color"
        }],
        "trigger": {
          "queryPatterns": [
            "find a brighter color for $SchemaOrg_Color:color"
          ]
        }
      }
    }
  ],
  "conversations": {
    "color-finder-echo": {
      "name": "color-finder-echo",
      "url": "https://grails-color-finder.appspot.com/assistantAction/index"
    },
    "color.intent": {
      "name": "color.intent",
      "url": "https://grails-color-finder.appspot.com/assistantAction/color"
    }
  }
}

As shown above, our app supports two actions. We explain those actions with more detail in the next sections of this guide.

We will need to modify the httpExecution items to match your deployed application endpoints.

src/main/resources/action.json

"url": "https://PROJECT_ID.appspot.com/assistantAction/index"

Add Actions to your assistant app

The first time you select a project in the Google Cloud Actions Console, you will need to supply the action package JSON via the gactions tool like so:

gactions update --action_package src/main/resources/action.json --project PROJECT_ID

Follow the instructions prompted by the above command. It involves an authorization process.

At the end you will see an output similar to:

Your app for the Assistant for project PROJECT_ID was successfully updated with your actions. Visit the Actions on Google console to finish registering your app and submit it for review at https://console.actions.google.com/project/PROJECT_ID/overview

Add App Information

After you actions package has been validated, you will be able to enter directory information such as images, privacy policy, and descriptions. Here you can also pick the voice of the speaker in your skill.

The previous screenshots display two buttons. Test and Submit. We will click the Test in the previous screenshots once we have deployed our app to Google App Engine Flexible and we are ready to test our actions.

3.4 Google App Engine

We are going to deploy the Grails application developed in this guide to the Google App Engine Flexible Environment

App Engine allows developers to focus on doing what they do best: writing code. Based on Google Compute Engine, the App Engine flexible environment automatically scales your app up and down while balancing the load. Microservices, authorization, SQL and NoSQL databases, traffic splitting, logging, versioning, security scanning, and content delivery networks are all supported natively.

Run the command:

$ gcloud app create

to initialize an App Engine application within the current Google Cloud project.

4 Writing the Application

4.1 Handle Request from Google in Grails

We name our app color finder. We want to achieve the scenario pictured below:

First, we are going to add a dependency to Google Actions Java SDK

/build.gradle

compile 'com.frogermcs.gactions:gactions:0.1.1'

The illustrated conversation is managed with the handlers. We instantiate the handlers with factories. Add the next classes to your app:

/src/main/groovy/demo/MainRequestHandlerFactory.groovy

package demo

import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import groovy.transform.CompileStatic

@CompileStatic
class MainRequestHandlerFactory extends RequestHandler.Factory {
    @Override
    RequestHandler create(RootRequest rootRequest) {
        new MainRequestHandler(rootRequest)
    }
}

/src/main/groovy/demo/MainRequestHandler.groovy

package demo

import com.frogermcs.gactions.ResponseBuilder
import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import com.frogermcs.gactions.api.response.RootResponse
import groovy.transform.CompileStatic

@CompileStatic
class MainRequestHandler extends RequestHandler {
    protected MainRequestHandler(RootRequest rootRequest) {
        super(rootRequest)
    }

    @Override
    RootResponse getResponse() {
        ResponseBuilder.askResponse('Hey, it works! Now tell something so I could repeat it.')
    }
}

/src/main/groovy/demo/MainRequestHandler.groovy

package demo

import com.frogermcs.gactions.ResponseBuilder
import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import com.frogermcs.gactions.api.response.RootResponse
import groovy.transform.CompileStatic

@CompileStatic
class MainRequestHandler extends RequestHandler {
    protected MainRequestHandler(RootRequest rootRequest) {
        super(rootRequest)
    }

    @Override
    RootResponse getResponse() {
        ResponseBuilder.askResponse('Hey, it works! Now tell something so I could repeat it.')
    }
}

/src/main/groovy/demo/TextRequestHandlerFactory.groovy

package demo

import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import groovy.transform.CompileStatic

@CompileStatic
class TextRequestHandlerFactory extends RequestHandler.Factory {
    @Override
    RequestHandler create(RootRequest rootRequest) {
        new TextRequestHandler(rootRequest)
    }
}

/src/main/groovy/demo/TextRequestHandler.groovy

package demo

import com.frogermcs.gactions.ResponseBuilder
import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import com.frogermcs.gactions.api.response.RootResponse
import groovy.transform.CompileStatic

@CompileStatic
class TextRequestHandler extends RequestHandler {
    protected TextRequestHandler(RootRequest rootRequest) {
        super(rootRequest)
    }

    @Override
    RootResponse getResponse() {
        ResponseBuilder.tellResponse("You just told: ${rootRequest.inputs.get(0).raw_inputs.get(0).query}")
    }
}

We are going to handle the request that come from Google in a Grails Controller:

A controller fulfills the C in the Model View Controller (MVC) pattern and is responsible for handling web requests. In Grails a controller is a class with a name that ends in the convention "Controller" and lives in the grails-app/controllers directory.

The Grails Controller, in turn, will delegate to Actions SDK.

/grails-app/controllers/demo/AssistantActionController.groovy

package demo

import com.frogermcs.gactions.AssistantActions
import com.frogermcs.gactions.api.StandardIntents
import com.frogermcs.gactions.api.request.RootRequest
import com.google.gson.Gson
import com.google.gson.stream.JsonReader
import javax.servlet.http.HttpServletRequest
import groovy.transform.CompileStatic

@CompileStatic
class AssistantActionController {
    def index() {
        AssistantActions assistantActions =
                new AssistantActions.Builder(new GrailsResponseHandler(response))
                        .addRequestHandlerFactory(StandardIntents.MAIN, new MainRequestHandlerFactory())  (1)
                        .addRequestHandlerFactory(StandardIntents.TEXT, new TextRequestHandlerFactory())
                        .build()
        RootRequest rootRequest = parseActionRequest(request)
        assistantActions.handleRequest(rootRequest) (2)
        null (3)
    }
    private RootRequest parseActionRequest(HttpServletRequest request) throws IOException {
        JsonReader jsonReader = new JsonReader(request.reader)
        new Gson().fromJson(jsonReader, RootRequest)
    }

1	We can chain handlers
2	Grails action delegates to Actions SDK to handle requests that come from Google.
3	We do not want to return a grails view. The handlers manage the response

Add GrailsResponseHandler to your project. As illustrated above, it allow us to use a controller to process the incoming requests.

/src/main/groovy/demo/GrailsResponseHandler.groovy

package demo

import com.frogermcs.gactions.ResponseHandler
import com.frogermcs.gactions.api.response.RootResponse
import com.google.gson.Gson
import groovy.transform.CompileStatic
import javax.servlet.http.HttpServletResponse
import groovy.util.logging.Slf4j

/**
 * This is a handler for the SDK to make it work with Grails properly
 */
@CompileStatic
@Slf4j
class GrailsResponseHandler implements ResponseHandler {
    private final HttpServletResponse httpServletResponse
    private final Gson gson

    GrailsResponseHandler(HttpServletResponse httpServletResponse) {
        this(httpServletResponse, new Gson())
    }

    GrailsResponseHandler(HttpServletResponse httpServletResponse, Gson gson) {
        this.httpServletResponse = httpServletResponse
        this.gson = gson
    }

    @Override
    void onPrepareContentType(String contentType) {
        httpServletResponse.setContentType(contentType)
    }

    @Override
    void onPrepareResponseHeaders(Map<String, String> headers) {
        for (String headerName : headers.keySet()) {
            httpServletResponse.addHeader(headerName, headers.get(headerName))
        }
    }

    @Override
    void onResponse(RootResponse rootResponse) {
        try {
            gson.toJson(rootResponse, httpServletResponse.writer)
            httpServletResponse.flushBuffer()
        } catch (IOException e) {
            log.error('Error writing response', e)
        }
    }

    String getResponse(RootResponse rootResponse) {

        try {
            gson.toJson(rootResponse)
        } catch (IOException e) {
            log.error('Error getting response', e)
        }
    }
}

4.2 Color Handler

To honor our app’s name we want to handle the next scenario as well:

Similar to the previous example. We need a handler and a factory to instantiate the handler.

This handler demonstrates passing a verbal parameter into the intent. When the user asks for a brighter color for X it will try to find a brighter color with a name and say it to the user.

/src/main/groovy/demo/ColorRequestHandlerFactory.groovy

package demo

import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import groovy.transform.CompileStatic

@CompileStatic
class ColorRequestHandlerFactory extends RequestHandler.Factory {
    @Override
    RequestHandler create(RootRequest rootRequest) {
        new ColorRequestHandler(rootRequest)
    }

}

/src/main/groovy/demo/ColorRequestHandler.groovy

package demo

import com.frogermcs.gactions.ResponseBuilder
import com.frogermcs.gactions.api.RequestHandler
import com.frogermcs.gactions.api.request.RootRequest
import com.frogermcs.gactions.api.response.RootResponse
import demo.util.ColorUtils
import java.awt.Color
import java.lang.reflect.Field
import groovy.transform.CompileStatic
import groovy.util.logging.Slf4j

/**
 * take a color name input and returns a brighter color name in return if possible
 */
@CompileStatic
@Slf4j
class ColorRequestHandler extends RequestHandler {

    protected ColorRequestHandler(RootRequest rootRequest) {
        super(rootRequest)
    }

    @Override
    RootResponse getResponse() {
        log.debug("Inputs=${rootRequest.inputs.toListString()}")
        String color = rootRequest.inputs[0].arguments[0].raw_text.toLowerCase()

        Color parsedColor = null
        try {
            Field field = Class.forName('java.awt.Color').getField(color)
            parsedColor = (Color)field.get(null)
        } catch (NoSuchFieldException ne) {
            return colorNotFound(color)
        }
        if (parsedColor) {
            ColorUtils colorUtils = new ColorUtils()
            String brighter = colorUtils.findBrighterNameForColor(parsedColor).toLowerCase()
            String answer = "Sorry I can't find a brighter color for ${color}."
            if (brighter != color) {
                answer = "The brighter color for ${color} is ${brighter} "
            }
            return ResponseBuilder.tellResponse(answer)
        }
        colorNotFound(color)
    }

    private RootResponse colorNotFound(String color) {
        ResponseBuilder.tellResponse("Sorry I don't understand the color ${color}.")
    }
}

We are going to handle the request that come from Google in another action of our controller:

/grails-app/controllers/demo/AssistantActionController.groovy

package demo

import com.frogermcs.gactions.AssistantActions
import com.frogermcs.gactions.api.StandardIntents
import com.frogermcs.gactions.api.request.RootRequest
import com.google.gson.Gson
import com.google.gson.stream.JsonReader
import javax.servlet.http.HttpServletRequest
import groovy.transform.CompileStatic

@CompileStatic
class AssistantActionController {
    def color() {
        AssistantActions assistantActions =
                new AssistantActions.Builder(new GrailsResponseHandler(response))
                        .addRequestHandlerFactory('color.intent', new ColorRequestHandlerFactory()) (1)
                        .build()
        RootRequest rootRequest = parseActionRequest(request)  (2)
        assistantActions.handleRequest(rootRequest)
        null  (3)
    }
    private RootRequest parseActionRequest(HttpServletRequest request) throws IOException {
        JsonReader jsonReader = new JsonReader(request.reader)
        new Gson().fromJson(jsonReader, RootRequest)
    }

1	Instantiate the handler with the help of the factory
2	Grails action delegates to Actions SDK to handle requests that come from Google.
3	We do not want to return a grails view. The handlers manage the response

Let’s use a simple utility class to make our action do something interesting. This will help us map a given java.awt.Color to give us a english name for it.

/src/main/groovy/demo/util/ColorUtils.java

package demo.util;

import java.awt.*;
import java.util.ArrayList;

/**
 * Java Code to get a color name from rgb/hex value/awt color
 *
 * The part of looking up a color name from the rgb values is edited from
 * https://gist.github.com/nightlark/6482130#file-gistfile1-java (that has some errors) by Ryan Mast (nightlark)
 *
 * @author Xiaoxiao Li
 *
 */
public class ColorUtils {

    /**
     * Initialize the color list that we have.
     */
    private ArrayList<ColorName> initColorList() {
        ArrayList<ColorName> colorList = new ArrayList<ColorName>();
        colorList.add(new ColorName("AliceBlue", 0xF0, 0xF8, 0xFF));
        colorList.add(new ColorName("AntiqueWhite", 0xFA, 0xEB, 0xD7));
        colorList.add(new ColorName("Aqua", 0x00, 0xFF, 0xFF));
        colorList.add(new ColorName("Aquamarine", 0x7F, 0xFF, 0xD4));
        colorList.add(new ColorName("Azure", 0xF0, 0xFF, 0xFF));
        colorList.add(new ColorName("Beige", 0xF5, 0xF5, 0xDC));
        colorList.add(new ColorName("Bisque", 0xFF, 0xE4, 0xC4));
        colorList.add(new ColorName("Black", 0x00, 0x00, 0x00));
        colorList.add(new ColorName("BlanchedAlmond", 0xFF, 0xEB, 0xCD));
        colorList.add(new ColorName("Blue", 0x00, 0x00, 0xFF));
        colorList.add(new ColorName("BlueViolet", 0x8A, 0x2B, 0xE2));
        colorList.add(new ColorName("Brown", 0xA5, 0x2A, 0x2A));
        colorList.add(new ColorName("BurlyWood", 0xDE, 0xB8, 0x87));
        colorList.add(new ColorName("CadetBlue", 0x5F, 0x9E, 0xA0));
        colorList.add(new ColorName("Chartreuse", 0x7F, 0xFF, 0x00));
        colorList.add(new ColorName("Chocolate", 0xD2, 0x69, 0x1E));
        colorList.add(new ColorName("Coral", 0xFF, 0x7F, 0x50));
        colorList.add(new ColorName("CornflowerBlue", 0x64, 0x95, 0xED));
        colorList.add(new ColorName("Cornsilk", 0xFF, 0xF8, 0xDC));
        colorList.add(new ColorName("Crimson", 0xDC, 0x14, 0x3C));
        colorList.add(new ColorName("Cyan", 0x00, 0xFF, 0xFF));
        colorList.add(new ColorName("DarkBlue", 0x00, 0x00, 0x8B));
        colorList.add(new ColorName("DarkCyan", 0x00, 0x8B, 0x8B));
        colorList.add(new ColorName("DarkGoldenRod", 0xB8, 0x86, 0x0B));
        colorList.add(new ColorName("DarkGray", 0xA9, 0xA9, 0xA9));
        colorList.add(new ColorName("DarkGreen", 0x00, 0x64, 0x00));
        colorList.add(new ColorName("DarkKhaki", 0xBD, 0xB7, 0x6B));
        colorList.add(new ColorName("DarkMagenta", 0x8B, 0x00, 0x8B));
        colorList.add(new ColorName("DarkOliveGreen", 0x55, 0x6B, 0x2F));
        colorList.add(new ColorName("DarkOrange", 0xFF, 0x8C, 0x00));
        colorList.add(new ColorName("DarkOrchid", 0x99, 0x32, 0xCC));
        colorList.add(new ColorName("DarkRed", 0x8B, 0x00, 0x00));
        colorList.add(new ColorName("DarkSalmon", 0xE9, 0x96, 0x7A));
        colorList.add(new ColorName("DarkSeaGreen", 0x8F, 0xBC, 0x8F));
        colorList.add(new ColorName("DarkSlateBlue", 0x48, 0x3D, 0x8B));
        colorList.add(new ColorName("DarkSlateGray", 0x2F, 0x4F, 0x4F));
        colorList.add(new ColorName("DarkTurquoise", 0x00, 0xCE, 0xD1));
        colorList.add(new ColorName("DarkViolet", 0x94, 0x00, 0xD3));
        colorList.add(new ColorName("DeepPink", 0xFF, 0x14, 0x93));
        colorList.add(new ColorName("DeepSkyBlue", 0x00, 0xBF, 0xFF));
        colorList.add(new ColorName("DimGray", 0x69, 0x69, 0x69));
        colorList.add(new ColorName("DodgerBlue", 0x1E, 0x90, 0xFF));
        colorList.add(new ColorName("FireBrick", 0xB2, 0x22, 0x22));
        colorList.add(new ColorName("FloralWhite", 0xFF, 0xFA, 0xF0));
        colorList.add(new ColorName("ForestGreen", 0x22, 0x8B, 0x22));
        colorList.add(new ColorName("Fuchsia", 0xFF, 0x00, 0xFF));
        colorList.add(new ColorName("Gainsboro", 0xDC, 0xDC, 0xDC));
        colorList.add(new ColorName("GhostWhite", 0xF8, 0xF8, 0xFF));
        colorList.add(new ColorName("Gold", 0xFF, 0xD7, 0x00));
        colorList.add(new ColorName("GoldenRod", 0xDA, 0xA5, 0x20));
        colorList.add(new ColorName("Gray", 0x80, 0x80, 0x80));
        colorList.add(new ColorName("Green", 0x00, 0x80, 0x00));
        colorList.add(new ColorName("GreenYellow", 0xAD, 0xFF, 0x2F));
        colorList.add(new ColorName("HoneyDew", 0xF0, 0xFF, 0xF0));
        colorList.add(new ColorName("HotPink", 0xFF, 0x69, 0xB4));
        colorList.add(new ColorName("IndianRed", 0xCD, 0x5C, 0x5C));
        colorList.add(new ColorName("Indigo", 0x4B, 0x00, 0x82));
        colorList.add(new ColorName("Ivory", 0xFF, 0xFF, 0xF0));
        colorList.add(new ColorName("Khaki", 0xF0, 0xE6, 0x8C));
        colorList.add(new ColorName("Lavender", 0xE6, 0xE6, 0xFA));
        colorList.add(new ColorName("LavenderBlush", 0xFF, 0xF0, 0xF5));
        colorList.add(new ColorName("LawnGreen", 0x7C, 0xFC, 0x00));
        colorList.add(new ColorName("LemonChiffon", 0xFF, 0xFA, 0xCD));
        colorList.add(new ColorName("LightBlue", 0xAD, 0xD8, 0xE6));
        colorList.add(new ColorName("LightCoral", 0xF0, 0x80, 0x80));
        colorList.add(new ColorName("LightCyan", 0xE0, 0xFF, 0xFF));
        colorList.add(new ColorName("LightGoldenRodYellow", 0xFA, 0xFA, 0xD2));
        colorList.add(new ColorName("LightGray", 0xD3, 0xD3, 0xD3));
        colorList.add(new ColorName("LightGreen", 0x90, 0xEE, 0x90));
        colorList.add(new ColorName("LightPink", 0xFF, 0xB6, 0xC1));
        colorList.add(new ColorName("LightSalmon", 0xFF, 0xA0, 0x7A));
        colorList.add(new ColorName("LightSeaGreen", 0x20, 0xB2, 0xAA));
        colorList.add(new ColorName("LightSkyBlue", 0x87, 0xCE, 0xFA));
        colorList.add(new ColorName("LightSlateGray", 0x77, 0x88, 0x99));
        colorList.add(new ColorName("LightSteelBlue", 0xB0, 0xC4, 0xDE));
        colorList.add(new ColorName("LightYellow", 0xFF, 0xFF, 0xE0));
        colorList.add(new ColorName("Lime", 0x00, 0xFF, 0x00));
        colorList.add(new ColorName("LimeGreen", 0x32, 0xCD, 0x32));
        colorList.add(new ColorName("Linen", 0xFA, 0xF0, 0xE6));
        colorList.add(new ColorName("Magenta", 0xFF, 0x00, 0xFF));
        colorList.add(new ColorName("Maroon", 0x80, 0x00, 0x00));
        colorList.add(new ColorName("MediumAquaMarine", 0x66, 0xCD, 0xAA));
        colorList.add(new ColorName("MediumBlue", 0x00, 0x00, 0xCD));
        colorList.add(new ColorName("MediumOrchid", 0xBA, 0x55, 0xD3));
        colorList.add(new ColorName("MediumPurple", 0x93, 0x70, 0xDB));
        colorList.add(new ColorName("MediumSeaGreen", 0x3C, 0xB3, 0x71));
        colorList.add(new ColorName("MediumSlateBlue", 0x7B, 0x68, 0xEE));
        colorList.add(new ColorName("MediumSpringGreen", 0x00, 0xFA, 0x9A));
        colorList.add(new ColorName("MediumTurquoise", 0x48, 0xD1, 0xCC));
        colorList.add(new ColorName("MediumVioletRed", 0xC7, 0x15, 0x85));
        colorList.add(new ColorName("MidnightBlue", 0x19, 0x19, 0x70));
        colorList.add(new ColorName("MintCream", 0xF5, 0xFF, 0xFA));
        colorList.add(new ColorName("MistyRose", 0xFF, 0xE4, 0xE1));
        colorList.add(new ColorName("Moccasin", 0xFF, 0xE4, 0xB5));
        colorList.add(new ColorName("NavajoWhite", 0xFF, 0xDE, 0xAD));
        colorList.add(new ColorName("Navy", 0x00, 0x00, 0x80));
        colorList.add(new ColorName("OldLace", 0xFD, 0xF5, 0xE6));
        colorList.add(new ColorName("Olive", 0x80, 0x80, 0x00));
        colorList.add(new ColorName("OliveDrab", 0x6B, 0x8E, 0x23));
        colorList.add(new ColorName("Orange", 0xFF, 0xA5, 0x00));
        colorList.add(new ColorName("OrangeRed", 0xFF, 0x45, 0x00));
        colorList.add(new ColorName("Orchid", 0xDA, 0x70, 0xD6));
        colorList.add(new ColorName("PaleGoldenRod", 0xEE, 0xE8, 0xAA));
        colorList.add(new ColorName("PaleGreen", 0x98, 0xFB, 0x98));
        colorList.add(new ColorName("PaleTurquoise", 0xAF, 0xEE, 0xEE));
        colorList.add(new ColorName("PaleVioletRed", 0xDB, 0x70, 0x93));
        colorList.add(new ColorName("PapayaWhip", 0xFF, 0xEF, 0xD5));
        colorList.add(new ColorName("PeachPuff", 0xFF, 0xDA, 0xB9));
        colorList.add(new ColorName("Peru", 0xCD, 0x85, 0x3F));
        colorList.add(new ColorName("Pink", 0xFF, 0xC0, 0xCB));
        colorList.add(new ColorName("Plum", 0xDD, 0xA0, 0xDD));
        colorList.add(new ColorName("PowderBlue", 0xB0, 0xE0, 0xE6));
        colorList.add(new ColorName("Purple", 0x80, 0x00, 0x80));
        colorList.add(new ColorName("Red", 0xFF, 0x00, 0x00));
        colorList.add(new ColorName("RosyBrown", 0xBC, 0x8F, 0x8F));
        colorList.add(new ColorName("RoyalBlue", 0x41, 0x69, 0xE1));
        colorList.add(new ColorName("SaddleBrown", 0x8B, 0x45, 0x13));
        colorList.add(new ColorName("Salmon", 0xFA, 0x80, 0x72));
        colorList.add(new ColorName("SandyBrown", 0xF4, 0xA4, 0x60));
        colorList.add(new ColorName("SeaGreen", 0x2E, 0x8B, 0x57));
        colorList.add(new ColorName("SeaShell", 0xFF, 0xF5, 0xEE));
        colorList.add(new ColorName("Sienna", 0xA0, 0x52, 0x2D));
        colorList.add(new ColorName("Silver", 0xC0, 0xC0, 0xC0));
        colorList.add(new ColorName("SkyBlue", 0x87, 0xCE, 0xEB));
        colorList.add(new ColorName("SlateBlue", 0x6A, 0x5A, 0xCD));
        colorList.add(new ColorName("SlateGray", 0x70, 0x80, 0x90));
        colorList.add(new ColorName("Snow", 0xFF, 0xFA, 0xFA));
        colorList.add(new ColorName("SpringGreen", 0x00, 0xFF, 0x7F));
        colorList.add(new ColorName("SteelBlue", 0x46, 0x82, 0xB4));
        colorList.add(new ColorName("Tan", 0xD2, 0xB4, 0x8C));
        colorList.add(new ColorName("Teal", 0x00, 0x80, 0x80));
        colorList.add(new ColorName("Thistle", 0xD8, 0xBF, 0xD8));
        colorList.add(new ColorName("Tomato", 0xFF, 0x63, 0x47));
        colorList.add(new ColorName("Turquoise", 0x40, 0xE0, 0xD0));
        colorList.add(new ColorName("Violet", 0xEE, 0x82, 0xEE));
        colorList.add(new ColorName("Wheat", 0xF5, 0xDE, 0xB3));
        colorList.add(new ColorName("White", 0xFF, 0xFF, 0xFF));
        colorList.add(new ColorName("WhiteSmoke", 0xF5, 0xF5, 0xF5));
        colorList.add(new ColorName("Yellow", 0xFF, 0xFF, 0x00));
        colorList.add(new ColorName("YellowGreen", 0x9A, 0xCD, 0x32));
        return colorList;
    }

    /**
     * Get the closest color name from our list
     *
     * @param r
     * @param g
     * @param b
     * @return
     */
    public String getColorNameFromRgb(int r, int g, int b) {
        ArrayList<ColorName> colorList = initColorList();
        ColorName closestMatch = null;
        int minMSE = Integer.MAX_VALUE;
        int mse;
        for (ColorName c : colorList) {
            mse = c.computeMSE(r, g, b);
            if (mse < minMSE) {
                minMSE = mse;
                closestMatch = c;
            }
        }

        if (closestMatch != null) {
            return closestMatch.getName();
        } else {
            return "No matched color name.";
        }
    }

    /**
     * Convert hexColor to rgb, then call getColorNameFromRgb(r, g, b)
     *
     * @param hexColor
     * @return
     */
    public String getColorNameFromHex(int hexColor) {
        int r = (hexColor & 0xFF0000) >> 16;
        int g = (hexColor & 0xFF00) >> 8;
        int b = (hexColor & 0xFF);
        return getColorNameFromRgb(r, g, b);
    }

    public int colorToHex(Color c) {
        return Integer.decode("0x"
                + Integer.toHexString(c.getRGB()).substring(2));
    }

    public String getColorNameFromColor(Color color) {
        return getColorNameFromRgb(color.getRed(), color.getGreen(),
                color.getBlue());
    }

    public String findBrighterNameForColor(Color color) {
        String name = getColorNameFromColor(color);
        String nextColorName = name;
        int colorCount = 0;
        while (name.equals(nextColorName) && colorCount < 100) {
            color = color.brighter();
            nextColorName = getColorNameFromColor(color);
            colorCount++;
        }
        return nextColorName;



    }

    public String findDarkerNameForColor(Color color) {
        String name = getColorNameFromColor(color);
        String nextColorName = name;
        int colorCount = 0;
        while (name.equals(nextColorName) && colorCount < 100) {
            color = color.darker();
            nextColorName = getColorNameFromColor(color);
            colorCount++;
        }
        return nextColorName;



    }

    /**
     * SubClass of ColorUtils. In order to lookup color name
     *
     * @author Xiaoxiao Li
     *
     */
    public class ColorName {
        public int r, g, b;
        public String name;

        public ColorName(String name, int r, int g, int b) {
            this.r = r;
            this.g = g;
            this.b = b;
            this.name = name;
        }

        public int computeMSE(int pixR, int pixG, int pixB) {
            return (int) (((pixR - r) * (pixR - r) + (pixG - g) * (pixG - g) + (pixB - b)
                    * (pixB - b)) / 3);
        }

        public int getR() {
            return r;
        }

        public int getG() {
            return g;
        }

        public int getB() {
            return b;
        }

        public String getName() {
            return name;
        }
    }
}

Previous class is a Java Class. Grails allows us to mix Groovy and Java code seamlessly.

4.3 Unofficial Google Actions Java SDK

The SDK is at https://github.com/frogermcs/Google-Actions-Java-SDK however all we need to do is edit our build.gradle to include the library.

/build.gradle

compile 'com.frogermcs.gactions:gactions:0.1.1'

4.4 Google App Engine Gradle Plugin

To deploy to App Engine, we are going to use the Google App Engine Gradle Plugin.

We need to modify build.gradle, add the plugin as a buildscript dependency and apply the plugin:

build.gradle

buildscript {
    repositories {
        mavenLocal()
        maven { url "https://repo.grails.org/grails/core" }
    }
    dependencies {
        classpath "org.grails:grails-gradle-plugin:$grailsVersion"
        classpath 'com.google.cloud.tools:appengine-gradle-plugin:1.1.1'
    }
}
...
apply plugin: 'com.google.cloud.tools.appengine'

4.5 Application Deployment Configuration

To deploy to Google App Engine, we need to add the file src/main/appengine/app.yaml

It describes the application’s deployment configuration:

/src/main/appengine/app.yaml

runtime: java
env: flex

runtime_config:
    jdk: openjdk8
    server: jetty9

health_check:
    enable_health_check: False

resources:
    cpu: 1
    memory_gb: 2.3

manual_scaling:
  instances: 1

Here, app.yaml specifies the runtime used by the app, and sets env: flex, specifying that the app uses the flexible environment.

The minimal app.yaml application configuration file shown above is sufficient for a simple Grails application. Depending on the size, complexity, and features that your application uses, you may need to change and extend this basic configuration file. For more information on what can be configured via app.yaml, please see the Configuring Your App with app.yaml guide.

For more information on how the Java runtime works, see Java 8 / Jetty 9.3 Runtime.

4.6 SpringBoot Jetty

As shown in the previous app engine configuration file, we are using Jetty.

Following SpringBoot’s documentation, we need to do the following changes to deploy to Jetty instead of Tomcat

Replace tomcat:

app/build.gradle

provided 'org.springframework.boot:spring-boot-starter-tomcat'

with jetty:

/build.gradle

provided "org.springframework.boot:spring-boot-starter-jetty"

We need to exclude the tomcat-juli dependency as well. Add:

/build.gradle

configurations {
    compile.exclude module: "tomcat-juli"
}

4.7 Deploying the App

To deploy the app to Google App Engine run:

$ ./gradlew appengineDeploy

Initial deployment may take a while. When finished, you will be able to access your app.

5 Test

5.1 Test and interact with your Google Action

Once your app is deployed in Google App Engine Flexible, you can test it.

Go back to the Google Actions Console and click test.

Try to test out your actions with the following phrases:

Ask to Grails Color Finder to find a brighter color for magenta

You should see the response:

Sure, here is the test version of Grails Color Finder The brighter color for magenta is fuchsia"

Let’s try another:

talk to Grails Color Finder

You’ll see:

Sure, here is the test version of Grails Color Finder Hey, it works! Now tell something so I could repeat it.

Now respond with something:

Grails is awesome

You should see it echo back what you entered:

You just told: Grails is awesome

Now you can make a more rich skill, and when you are ready go to the Google API dashboard, fill in the directory listing and submit it for testing.

1 Grails Training

2 Getting Started

2.1 What you will need

2.2 How to complete the guide

3 Google Cloud Settings

3.1 Create a Google Cloud Project

3.2 Install gactions CLI

3.3 Configure Google Actions

Enable Google Actions API

Import your Project to the Google Actions Console

Configure your project ID in action.json

Add Actions to your assistant app

Add App Information

3.4 Google App Engine

4 Writing the Application

4.1 Handle Request from Google in Grails

4.2 Color Handler

4.3 Unofficial Google Actions Java SDK

4.4 Google App Engine Gradle Plugin

4.5 Application Deployment Configuration

4.6 SpringBoot Jetty

4.7 Deploying the App

5 Test

5.1 Test and interact with your Google Action

Configure your project ID in `action.json`