ZK goes EC2 (Part 3)

November 25, 2011

ZK goes EC2 (Part 3)

Filed under: tutorial,zk,amazon aws — devdude @ 9:44 pm
Tags: netbeans, plugin, zk, sdk, s3, ec2, aws, dyndns, instance, tag, reservation, endpoint

The third part of the tutorial where I improve a few things. I will not walk through the complete code but highlight a few important points and give you the complete sourcecode at the end.

To recap, my requirements:

I want to allow users in my company to start and stop instances on their own without them login to AWS console.
Only specific instances are available to them.
Avoid using elastic IP’s (you pay for them if they are not assigned)
Make it configurable

The improvements in this version:

Remove the hardcoded access keys and place them encrypted in a properties file.
Only instances that are not protected can be started or stopped.
Update DynDNS entries from the application
Some cosmetic cleanup of the control panel

Running Application

Prerequisites:

The project from part 1 and 2 (link)

Important points:

Read from and write to properties files
The file will be located in our domain folder. We encrypt the password and secret access key.

Properties File

properties
Encryption
Encryption
Update DynDNS
This we can avoid paying for unused elastic IP’s since our instances only run occasionally.
I use a tag in the instance properties for the dyndns name

DynDNS Hostname

AWS instance tag

Update Method

Complete sourcecode:

instances.zul

<?xml version="1.0" encoding="UTF-8"?>

<zk xmlns="http://www.zkoss.org/2005/zul">
    <style dynamic="true">
            .style1 {
            font-family: monospace, courier;font-size: 13px; }
    </style>

    <window id="list" apply="controller.instancesControllerX" title="ZK EC2 CloudControl 0.2" width="100%">

        <listbox id="lstInstance" width="100%" >
            <listhead sizable="true">
                <listheader  label="Instance ID"/>
                <listheader label="Name"/>
                <listheader  label="Public IP" />
                <listheader  label="DynDNS" />
                <listheader  label="State" />
                <listheader  label="Protected" />
                <listheader  label="Launch Time" />
            </listhead>
        </listbox>
        <separator bar="true"/>

        <grid width="100%" >
            <columns>
                <column label="" width="10%"/>
                <column label=""/>
            </columns>
            <rows>
                <row>
                    <label value="Selected Endpoint" />
                    <label sclass="style1" id="lblEndpoint"/>
                </row>

                <row>
                    <label value="Status:" />
                    <label sclass="style1" id="lblStatus"/>
                </row>
                <row>
                    <button width="120px" id="btnReconnect" label="Reconnect" />
                    <button width="120px" id="btnRefresh" label="Refresh" />
                </row>
                <row>
                    <button width="120px" id="btnStart" label="Start instance" />
                    <button width="120px" id="btnStop" label="Stop instance" />
                </row>
                 <row>
                    <label/>
                    <button width="120px" id="btnDynDNS" label="Update DynDNS" />
                </row>
                <row>
                    <button width="120px" id="btnEndPoints" label="Show endpoints" onClick='regions.open(list,"overlap")'/>
                    <button width="120px" id="btnkeys" label="Settings" onClick='ec2keys.open(list,"overlap")'/>
                </row>
            </rows>
        </grid>

        <popup id="regions" width="350px" >
            <listbox id="lstRegion" width="100%">
                <listhead sizable="true" >
                    <listheader id="a" label="Region Name"/>
                    <listheader id="b" label="Region Endpoint" />
                </listhead>
            </listbox>
            <button id="btnSelectEndpoint" label="Select Endpoint" onClick=""/>
            <button id="btnCloseEndPoints" label="Close" onClick='regions.close()'/>
        </popup>

        <popup id="ec2keys" width="450px" >
            <grid>
                <columns>
                    <column label="" width="30%"/>
                    <column label=""/>
                </columns>
                <rows>
                    <row>
                        <label value="AWS Access Key"/>
                        <textbox id="txtKey" cols="40"/>
                    </row>
                    <row>
                        <label value="AWS Secret Access Key"/>
                        <textbox id="txtSkey" cols="40" type="password"/>
                    </row>
                    <row>
                        <label value="DynDNS Username"/>
                        <textbox id="txtDynUser" cols="40"/>
                    </row>
                    <row>
                        <label value="DynDNS Password"/>
                        <textbox id="txtDynPw" cols="40" type="password"/>
                    </row>
                    <row>
                        <button id="btnSaveKeys" label="Save Settings" />
                        <button id="btnCloseKeys" label="Close" onClick='ec2keys.close()'/>
                    </row>
                </rows>
            </grid>
        </popup>
    </window>
</zk>

instancesController.java

package controller;

import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.services.ec2.AmazonEC2;
import com.amazonaws.services.ec2.AmazonEC2Client;
import com.amazonaws.services.ec2.model.DescribeInstancesResult;
import com.amazonaws.services.ec2.model.DescribeRegionsResult;
import com.amazonaws.services.ec2.model.Instance;
import com.amazonaws.services.ec2.model.InstanceState;
import com.amazonaws.services.ec2.model.Region;
import com.amazonaws.services.ec2.model.Reservation;
import com.amazonaws.services.ec2.model.StartInstancesRequest;
import com.amazonaws.services.ec2.model.StartInstancesResult;
import com.amazonaws.services.ec2.model.StopInstancesRequest;
import com.amazonaws.services.ec2.model.StopInstancesResult;
import com.amazonaws.services.ec2.model.Tag;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.event.EventListener;
import org.zkoss.zk.ui.event.Events;
import org.zkoss.zk.ui.util.Clients;
import org.zkoss.zk.ui.util.ComposerExt;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Button;
import org.zkoss.zul.Label;
import org.zkoss.zul.ListModelList;
import org.zkoss.zul.Listbox;
import org.zkoss.zul.Listcell;
import org.zkoss.zul.Listitem;
import org.zkoss.zul.ListitemRenderer;
import org.zkoss.zul.Messagebox;
import org.zkoss.zul.Popup;
import org.zkoss.zul.Textbox;
import org.zkoss.zul.Window;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class instancesControllerX extends GenericForwardComposer implements ComposerExt {

    // ZK Variables
    private Listbox lstInstance;
    private Listbox lstRegion;
    private Label lblStatus;
    private Label lblEndpoint;
    private Button btnStart;
    private Button btnStop;
    private Button btnRefresh;
    private Button btnEndPoints;
    private Button btnDynDNS;
    private Textbox txtKey;
    private Textbox txtSkey;
    private Textbox txtDynPw;
    private Textbox txtDynUser;
    private Popup regions;
    private Popup ec2keys;
    private Window list;
    //Amazon Variables
    AmazonEC2 ec2;
    List<Reservation> listEC2Reservations = null;
    List<Instance> listEC2Instances = null;
    List<Region> listEC2Regions = null;
    //Others
    String msgboxTitle = "ZKEC2CloudControl";
    String defEndpoint = "ec2.ap-southeast-1.amazonaws.com";
    static String crypKey = "somekey";
    static String propFile = "ec2cloudcontrol.properties";
    String accessKey = "";
    String secretAccessKey = "";
    String endPoint = "";
    String dynDNSuser = "";
    String dynDNSpw = "";
    boolean ec2Conn = false;

    private void initEC2() {

        try {
            BasicAWSCredentials ecProp = new BasicAWSCredentials(accessKey, secretAccessKey);
            ec2 = new AmazonEC2Client(ecProp);
            ec2.setEndpoint(endPoint);

            // Retrieve the available EC2 regions
            DescribeRegionsResult regionsResult = ec2.describeRegions();
            listEC2Regions = regionsResult.getRegions();
            lstRegion.setModel(new ListModelList(listEC2Regions));

            ec2Conn = true;
            lblStatus.setValue("Connected.");

            btnRefresh.setDisabled(false);
            btnEndPoints.setDisabled(false);

        } catch (Exception ex) {
            ec2Conn = false;
            lblStatus.setValue(ex.getMessage());
            btnRefresh.setDisabled(true);
            btnEndPoints.setDisabled(true);
        }
    }

    @Override
    public void doAfterCompose(Component comp) throws Exception {
        super.doAfterCompose(comp);

        btnStart.setDisabled(true);
        btnStop.setDisabled(true);
        btnRefresh.setDisabled(true);

        if (readProperties()) {
            if (endPoint.isEmpty()) {
                endPoint = defEndpoint;
            }
            txtKey.setValue(accessKey);
            txtSkey.setValue(secretAccessKey);
            txtDynPw.setValue(dynDNSpw);
            txtDynUser.setValue(dynDNSuser);
            initEC2();
        } else {
            lblStatus.setValue("Missing AWS keys.");
        }

        setupRenderer();

        lblEndpoint.setValue(endPoint);
        if (ec2Conn) {
            listReservationsInstances();
        }

    }

    private void listReservationsInstances() {

        btnStart.setDisabled(true);
        btnStop.setDisabled(true);
        btnDynDNS.setDisabled(true);
        Clients.showBusy("Retrieving instance information..");
        Events.echoEvent("onListReservationsInstances", list, null);
    }

    public void onListReservationsInstances(Event event) {

        DescribeInstancesResult describeInstancesRequest = ec2.describeInstances();
        listEC2Reservations = describeInstancesRequest.getReservations();

        Set<Instance> instances = new HashSet<Instance>();
        for (Reservation reservation : listEC2Reservations) {
            instances.addAll(reservation.getInstances());
        }

        listEC2Instances = new ArrayList<Instance>(instances);

        lstInstance.setModel(new ListModelList(listEC2Instances));
        lblStatus.setValue("Loaded " + listEC2Instances.size() + " instances.");
        Clients.clearBusy();

    }

    public void onClick$btnRefresh(Event evt) throws InterruptedException {
        listReservationsInstances();
        lblStatus.setValue("");
    }

    public void onClick$btnReconnect(Event evt) throws InterruptedException {
        lblStatus.setValue("");
        listEC2Instances.clear();
        lstInstance.setModel(new ListModelList(listEC2Instances));
        initEC2();
    }

    public void onClick$btnSelectEndpoint(Event evt) throws InterruptedException {
        if (lstRegion.getSelectedIndex() > -1) {
            String newEndpoint = ((Region) lstRegion.getSelectedItem().getValue()).getEndpoint();
            ec2.setEndpoint(newEndpoint);
            lblEndpoint.setValue(newEndpoint);
            listReservationsInstances();
            regions.close();
        }
    }

    public void onClick$btnStart(Event evt) throws InterruptedException {
          if (lstInstance.getSelectedIndex() > -1) {
            Messagebox.show("Start instance <" + ((Instance) lstInstance.getSelectedItem().getValue()).getInstanceId() + "> ?", msgboxTitle, Messagebox.OK | Messagebox.CANCEL,
                    Messagebox.QUESTION,
                    new EventListener() {

                        public void onEvent(Event evt) {
                            switch (((Integer) evt.getData()).intValue()) {
                                case Messagebox.OK:
                                    doStart();
                                    break; //the Yes button is pressed
                            }
                        }
                    });
        }
    }

    private void doStart() {
        List<String> startIDs = new ArrayList<String>();
        startIDs.add(((Instance) lstInstance.getSelectedItem().getValue()).getInstanceId());
        StartInstancesRequest start = new StartInstancesRequest(startIDs);
        StartInstancesResult result = ec2.startInstances(start);
        lblStatus.setValue(result.toString() + " Refresh after 10 or more seconds.");

    }

    public void onClick$btnStop(Event evt) throws InterruptedException {

          if (lstInstance.getSelectedIndex() > -1) {
            Messagebox.show("Stop instance <" + ((Instance) lstInstance.getSelectedItem().getValue()).getInstanceId() + "> ?", msgboxTitle, Messagebox.OK | Messagebox.CANCEL,
                    Messagebox.QUESTION,
                    new EventListener() {

                        public void onEvent(Event evt) {
                            switch (((Integer) evt.getData()).intValue()) {
                                case Messagebox.OK:
                                    doStop();
                                    break; //the Yes button is pressed
                            }
                        }
                    });
        }
    }

    private void doStop() {
        List<String> stopIDs = new ArrayList<String>();
        stopIDs.add(((Instance) lstInstance.getSelectedItem().getValue()).getInstanceId());
        StopInstancesRequest stop = new StopInstancesRequest(stopIDs);
        StopInstancesResult result = ec2.stopInstances(stop);
        lblStatus.setValue(result.toString() + " Refresh after 10 or more seconds.");
    }

    public void onClick$btnSaveKeys(Event evt) throws InterruptedException {

        accessKey = txtKey.getValue();
        secretAccessKey = txtSkey.getValue();
        dynDNSpw = txtDynPw.getValue();
        dynDNSuser = txtDynUser.getValue();

        if (endPoint.isEmpty()) {
            endPoint = defEndpoint;
        }

        if (writeProperties()) {
            lblStatus.setValue("Configuration saved. Please reconnect.");
        }

        ec2keys.close();
    }

    public void onClick$btnDynDNS(Event evt) throws InterruptedException {

        if (lstInstance.getSelectedIndex() > -1) {
            String ip = ((Instance) lstInstance.getSelectedItem().getValue()).getPublicIpAddress();
            String dynDNShost = findTagValuebyKey(((Instance) lstInstance.getSelectedItem().getValue()).getTags(), "dyndns");

            // only instance with dns hostnames
            if (!dynDNShost.toUpperCase().equals("NA")) {

                    String feedback = updateDynDNS(dynDNShost, ip);
                    lblStatus.setValue(feedback);

            } else {
                lblStatus.setValue("No dynDNS hostname configured. Cannot be attached.");
            }
        }
    }

    public void onSelect$lstInstance(Event evt) throws InterruptedException {

        InstanceState state = ((Instance) lstInstance.getSelectedItem().getValue()).getState();
        String prot = findTagValuebyKey(((Instance) lstInstance.getSelectedItem().getValue()).getTags(), "protected");
        String dyndns = findTagValuebyKey(((Instance) lstInstance.getSelectedItem().getValue()).getTags(), "dyndns");

        btnStart.setDisabled(true);
        btnStop.setDisabled(true);
        btnDynDNS.setDisabled(true);

        if ((state.getCode() == 16) && (prot.equalsIgnoreCase("na"))) {
            btnStop.setDisabled(false);
            if (!dyndns.equalsIgnoreCase("na"))
                btnDynDNS.setDisabled(false);
        }

        if ((state.getCode() == 80) && (prot.equalsIgnoreCase("na"))) {
            btnStart.setDisabled(false);
        }
    }

    private void setupRenderer() {

        // EC2 Instances list renderer
        ListitemRenderer listRenderInstance = new ListitemRenderer() {

            @Override
            public void render(Listitem item, Object data) throws Exception {
                item.setValue(data);
                item.appendChild(new Listcell(((Instance) data).getInstanceId()));
                item.appendChild(new Listcell(findTagValuebyKey(((Instance) data).getTags(), "name")));
                item.appendChild(new Listcell(((Instance) data).getPublicIpAddress()));

                String dyndns = findTagValuebyKey(((Instance) data).getTags(), "dyndns");
                if (dyndns.equalsIgnoreCase("na")) {
                    item.appendChild(new Listcell(" "));
                } else {
                    item.appendChild(new Listcell(dyndns));
                }

                InstanceState state = ((Instance) data).getState();
                item.appendChild(new Listcell(state.getName()));

                String prot = findTagValuebyKey(((Instance) data).getTags(), "protected");
                if (prot.equalsIgnoreCase("yes")) {
                    item.appendChild(new Listcell("Yes"));
                } else {
                    item.appendChild(new Listcell(" "));
                }

                if (state.getCode() == 16) {
                    item.appendChild(new Listcell(((Instance) data).getLaunchTime().toString()));
                } else {
                    item.appendChild(new Listcell(" "));
                }

                Listcell listcell = new Listcell();
                item.appendChild(listcell);
            }
        };
        lstInstance.setItemRenderer(listRenderInstance);

        // EC2 Regions list renderer
        ListitemRenderer listitem = new ListitemRenderer() {

            @Override
            public void render(Listitem item, Object data) throws Exception {
                item.setValue(data);
                item.appendChild(new Listcell(((Region) data).getRegionName()));
                item.appendChild(new Listcell(((Region) data).getEndpoint()));
                Listcell listcell = new Listcell();
                item.appendChild(listcell);
            }
        };
        lstRegion.setItemRenderer(listitem);
    }

    // HELPER METHODS
    private String findTagValuebyKey(List<Tag> tags, String key) {

        for (Tag tag : tags) {
            if (tag.getKey().toUpperCase().equals(key.toUpperCase())) {
                return tag.getValue();
            }
        }
        return "na";
    }

    private String encryptString(String inStr) {
        try {
            DESKeySpec keySpec = new DESKeySpec(crypKey.getBytes("UTF8"));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);
            sun.misc.BASE64Encoder base64encoder = new BASE64Encoder();

            byte[] cleartext = inStr.getBytes("UTF8");
            Cipher cipher = Cipher.getInstance("DES"); // cipher is not thread safe
            cipher.init(Cipher.ENCRYPT_MODE, key);
            String encrypted = base64encoder.encode(cipher.doFinal(cleartext));

            return encrypted;
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            return null;
        }
    }

    private String decryptString(String inStr) {
        try {
            DESKeySpec keySpec = new DESKeySpec(crypKey.getBytes("UTF8"));
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            SecretKey key = keyFactory.generateSecret(keySpec);
            sun.misc.BASE64Decoder base64decoder = new BASE64Decoder();

            byte[] encrypedBytes = base64decoder.decodeBuffer(inStr);

            Cipher cipher = Cipher.getInstance("DES");
            cipher.init(Cipher.DECRYPT_MODE, key);
            byte[] plainText = (cipher.doFinal(encrypedBytes));

            return new String(plainText);
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            return null;
        }
    }

    private boolean readProperties() {
        Properties properties = new Properties();
        try {
            properties.load(new FileInputStream(propFile));
            accessKey = decryptString(properties.getProperty("accesskey"));
            secretAccessKey = decryptString(properties.getProperty("secretaccesskey"));
            endPoint = properties.getProperty("endpoint", "");
            dynDNSuser = properties.getProperty("dyndnsuser", "");
            dynDNSpw = decryptString(properties.getProperty("dyndnspw", ""));

            if ((accessKey.isEmpty()) || secretAccessKey.isEmpty()) {
                return false;
            } else {
                return true;
            }

        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            return false;

        }
    }

    private boolean writeProperties() {

        Properties properties = new Properties();
        properties.setProperty("accesskey", encryptString(accessKey));
        properties.setProperty("secretaccesskey", encryptString(secretAccessKey));
        properties.setProperty("endpoint", endPoint);
        properties.setProperty("dyndnspw", encryptString(dynDNSpw));
        properties.setProperty("dyndnsuser", dynDNSuser);

        try {
            properties.store(new FileOutputStream(propFile), null);
            return true;
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            return false;
        }

    }

    private String updateDynDNS(String hostName, String hostIP) {

        String userName = dynDNSuser;
        String userPassword = dynDNSpw;
        int responseCode;
        String feedback = "";

        try {
            // Encode username and password
            BASE64Encoder enc = new sun.misc.BASE64Encoder();
            String userpassword = userName + ":" + userPassword;
            String encodedAuthorization = enc.encode(userpassword.getBytes());

            // Connect to DynDNS
            URL url = new URL("http://members.dyndns.org/nic/update?hostname=" + hostName + "&myip=" + hostIP);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setRequestProperty("User-Agent", "DynDNS Updater");
            connection.setRequestProperty("Authorization", "Basic " + encodedAuthorization);

            // Execute GET
            responseCode = connection.getResponseCode();
            System.out.println(responseCode + ":" + connection.getResponseMessage());

            // Print feedback
            String line;
            InputStreamReader in = new InputStreamReader((InputStream) connection.getContent());
            BufferedReader buff = new BufferedReader(in);
            do {
                line = buff.readLine();
                if (line != null) {
                    feedback = line;
                }
                System.out.println(line);
            } while (line != null);

            connection.disconnect();

        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            feedback = ex.getMessage();
        }
        return feedback;
    }
}

The JavaDude Weblog

November 25, 2011

ZK goes EC2 (Part 3)

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November 25, 2011

ZK goes EC2 (Part 3)

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