MicroServices with Devops Example
In this post I show you How to create Micro service
application and Manage it through Dev-ops.
To understand MicroServices please look at my blog post
To understand Devops please look at my blog post
Tools are Used to implement Microservice
1.
Eclipse as Editor
2.
Java as Language
3.
Using REST Service to communicate between Microservices
4.
Maven as build tool
5.
Tomcat as Web server.
Tool are Used to Manage Microservices using Devops
1.
Jenkins as CI (Continous integration server).
2.
GitHub as SCM(Source control Management).
My intent is creating two Micro services
1.
An Order Service
2.
A Billing service
If client order for a product, Order Service project will communicate with Billing service project by REST
API. Billing Service returns Product price if exists in the Product Catalog
Otherwise It return a Message Product
not found.
Order service
accept this response and generate a new response
to Client.
To Manage these Microservice,
I using Devops
So that Two can be
deployed independently, and Two projects are hosted in
GitHub. If
someone do a change the code and push
it in Github a build has been triggered
by Jenkins and Once build is completed,
Jenkins install the artifact that is the war file in Local Repo (maven Local REPO) then deploy it to Tomcat Server.
No Manual
intervention is needed.
I have made it very
simple but in real time there will be much more complexity than two simple services
and we need Monitoring tool for health check for different projects which is
absent in this example.
I have used Java for Two
services but real time one could be in java another in PHP or Node JS any
language.
Installation:
Java: Install java from
Set JAVA_HOME in environment variables to java installation
path.
Eclipse : https://eclipse.org/downloads/
Download Tomcat 6 Zip Version and extract it in your local
drive that will your Tomcat installation directory.
Maven:
Download maven from https://maven.apache.org/download.cgi
Extract the zip in your local file Set M2_Home as maven
Installation path in your local directory.
Go to Git Command prompt after installation
Change Directory to C: Using Cd ../../
Now apply command (Need Internet connection)
after completing
again hit
Import two project in
to Eclipse by import from local option.
If you want to create
your new repositories, please go to Jenkins setup section and follow the step.
I prefer you create
your new repositories to work independently. Unless if you clone it you will be
dependent on me. If I gave you permission, then only you can push change on my
project.
Jenkins :
http://mirrors.jenkins-ci.org/war-stable/ (Take stable release. I use 1.65). Download
war and deploy it to <Tomcat_installation_path>/webapps. In tomcat
console when a message shows
“Jenkins full up and
running” go to browser hit
First thing you need
to require add plugins in to your local Jenkins Server
So Follow the steps
Go to Manage Jenkins from left panel
Go to manage Plugin
In Available Tab Search
with “git” and check gitplugin and github plugin
Hit install without restart button
Wait until installation finished.
Go to configure
system from manage plugin
Create an account in GitHub and then add your username and
your email Id.
Then Go to new Item create a Maven project.
Create a Job Name as “BuildandDeploy MicroOrderService”
Please see the following Screen shot
In the Source code management section set your Git repository URL
If you download source code from Git by download Zip and
create your new repository and push the code
Steps are
After Download
project from
and
using “ CloneorDownload”
button on GitHub
Extract Zip files
Create a project on Github using “+” button (Create new)
You will get a url like https://github.com/shami83/<projectname>.git
Execute following commands
for two projects in your local computer
Go to Git cmd
Go to the homefolder
of the Extract project
a. git init
b. git add .
c. git commit -m “demo”
d. git push origin master
Please do the steps
for two projects that will create two repositories in Git (require internet
connection).
In jenkins on repository
url put the url
If you clone it then
you need my permission to push code to my stream, please send me a mail the at
mitrashamik@gmail.com or add a comment
in blog.
Then put your credentials in credential section your
username and password of Git repository.
Follow next step
In Build triggers section Check ” BuildWhen a change pushed to Git hub”
And poll SCM
Put value as * * * * * in schedule text-area
This will detect if any changes
pushed on GitHub repository. If so this Jenkins target will run
Now Go to Build section
Set Root POM as pom.xml as you can
see a workspace folder create under your Jenkins target where Jenkins pull the
codebase from Git server and build it locally.
Set Goals and Option as clean install.
Install step is requires as it maintains your artifacts in your local maven
repository.
Last I want to deploy it on Tomcat server
To do that follow the following steps
First go to Tomcat installation directory
under conf folder
Open tomcat-users.xml in edit mode
Add following lines under
<tomcat-users> tag.
<role rolename="tomcat"/>
<role
rolename="role1"/>
<user
username="tomcat" password="tomcat"
roles="admin,manager-script,manager-gui"/>
<user
username="both" password="tomcat"
roles="tomcat,role1"/>
<user
username="role1" password="tomcat"
roles="role1"/>
Then go to Jenkins job configure section
In War/EAR files put
target\MicroOrderService.war as maven generates artifacts in target directory.
After that Set user name as tomcat
in Tomcat6.x section password is tomcat
Tomcat Url is http://localhost:8080
Click save button that will create
MicroOrderService job.
To check hit BuildNow button and go to console
output, you will see
Jenkins pull code from GitHub then
build it using maven install the artifacts then deploy it in your Tomcat Server
Perform Same thing for Billingservice,
create a new Job and configure that.
Now to Check just make a change in
Source code
Push it to Git using Git Cmd
Steps
git add .
git commit -m ”change”
git push origin master
go to Jenkins dashboard you will
see a build is initiated and deployed.
Main Classes in Micro Order Source Code
OrderService.java
package com.microservice.order;
import java.io.IOException;
import java.io.StringReader;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import com.microservice.model.BillingStatus;
import com.microservice.model.OrderStatus;
@Path("/order")
public class OrderService {
@GET
@Path("{name}")
@Produces(MediaType.TEXT_XML)
public OrderStatus getOrderStatus(@PathParam("name") String name)
throws ClientProtocolException, IOException {
System.out.println("Orerd Item name is ==>" + name);
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet getRequest = new HttpGet(
"http://localhost:8080/billingservice/billingservice/billing/"
+ name);
String response = getResponse(httpClient, getRequest);
BillingStatus stat = new BillingStatus();
stat = this.converStringToObject(stat, response);
System.out.println("Return Object from JAXB " + stat);
OrderStatus status = new OrderStatus();
status.setOrderName(stat.getItem());
status.setOrderCost(stat.getPrice());
return status;
}
public String getResponse(DefaultHttpClient client, HttpGet request) {
HttpResponse response = null;
String apiOutput = null;
try {
response = client.execute(request);
// verify the valid error code first
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != 200) {
throw new RuntimeException("Failed with HTTP error code : "
+ statusCode);
}
HttpEntity httpEntity = response.getEntity();
apiOutput = EntityUtils.toString(httpEntity);
System.out.println(apiOutput);
} catch (Exception ex) {
ex.printStackTrace();
}
return apiOutput;
}
public <T> T converStringToObject(T t, String res) {
try {
JAXBContext jaxbContext = JAXBContext.newInstance(t.getClass());
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
t = (T) jaxbUnmarshaller.unmarshal(new StringReader(res));
} catch (JAXBException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return t;
}
}
import java.io.StringReader;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import com.microservice.model.BillingStatus;
import com.microservice.model.OrderStatus;
@Path("/order")
public class OrderService {
@GET
@Path("{name}")
@Produces(MediaType.TEXT_XML)
public OrderStatus getOrderStatus(@PathParam("name") String name)
throws ClientProtocolException, IOException {
System.out.println("Orerd Item name is ==>" + name);
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet getRequest = new HttpGet(
"http://localhost:8080/billingservice/billingservice/billing/"
+ name);
String response = getResponse(httpClient, getRequest);
BillingStatus stat = new BillingStatus();
stat = this.converStringToObject(stat, response);
System.out.println("Return Object from JAXB " + stat);
OrderStatus status = new OrderStatus();
status.setOrderName(stat.getItem());
status.setOrderCost(stat.getPrice());
return status;
}
public String getResponse(DefaultHttpClient client, HttpGet request) {
HttpResponse response = null;
String apiOutput = null;
try {
response = client.execute(request);
// verify the valid error code first
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != 200) {
throw new RuntimeException("Failed with HTTP error code : "
+ statusCode);
}
HttpEntity httpEntity = response.getEntity();
apiOutput = EntityUtils.toString(httpEntity);
System.out.println(apiOutput);
} catch (Exception ex) {
ex.printStackTrace();
}
return apiOutput;
}
public <T> T converStringToObject(T t, String res) {
try {
JAXBContext jaxbContext = JAXBContext.newInstance(t.getClass());
Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
t = (T) jaxbUnmarshaller.unmarshal(new StringReader(res));
} catch (JAXBException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return t;
}
}
Main Class in Billing service Module
package com.microservice.billing.service;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import com.microservice.billing.model.BillStatus;
import com.microservice.billing.utility.PriceCatalog;
@Path("/billing")
public class BillingService {
@GET
@Path("{name}")
@Produces(MediaType.TEXT_XML)
public BillStatus getOrderStatus(@PathParam("name")String name)
{
System.out.println("Check Item in Inventory ==>" + name);
return PriceCatalog.getCatalog().getStatus(name.toLowerCase());
}
}
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import com.microservice.billing.model.BillStatus;
import com.microservice.billing.utility.PriceCatalog;
@Path("/billing")
public class BillingService {
@GET
@Path("{name}")
@Produces(MediaType.TEXT_XML)
public BillStatus getOrderStatus(@PathParam("name")String name)
{
System.out.println("Check Item in Inventory ==>" + name);
return PriceCatalog.getCatalog().getStatus(name.toLowerCase());
}
}
PriceCatalog.java
package com.microservice.billing.utility;
import java.util.HashMap;
import java.util.Map;
import com.microservice.billing.model.BillStatus;
public class PriceCatalog {
private static PriceCatalog calalog=new PriceCatalog();
private Map<String,String> priceMap=new HashMap<String,String>();
private PriceCatalog()
{
init();
}
private void init()
{
priceMap.put("pen", "10");
priceMap.put("shirt", "1000");
priceMap.put("televison", "20000");
priceMap.put("ac", "30000");
priceMap.put("smartphone", "14000");
priceMap.put("radio", "2000");
priceMap.put("musicbox", "20000");
priceMap.put("bike", "66000");
priceMap.put("scooter", "26000");
priceMap.put("pant", "100");
priceMap.put("harddisc", "3000");
// end of map
}
public static PriceCatalog getCatalog()
{
return calalog;
}
public BillStatus getStatus(String key)
{
BillStatus status= new BillStatus();
if(key == null || priceMap.get(key)==null)
{
status.setItem("Sorry" + key + " Not found in Inventory!!");
status.setPrice("Not Applicable");
return status;
}
status.setItem(key.toUpperCase());
String price = priceMap.get(key) + " Rupees only.";
status.setPrice(price);
return status;
}
}
import java.util.HashMap;
import java.util.Map;
import com.microservice.billing.model.BillStatus;
public class PriceCatalog {
private static PriceCatalog calalog=new PriceCatalog();
private Map<String,String> priceMap=new HashMap<String,String>();
private PriceCatalog()
{
init();
}
private void init()
{
priceMap.put("pen", "10");
priceMap.put("shirt", "1000");
priceMap.put("televison", "20000");
priceMap.put("ac", "30000");
priceMap.put("smartphone", "14000");
priceMap.put("radio", "2000");
priceMap.put("musicbox", "20000");
priceMap.put("bike", "66000");
priceMap.put("scooter", "26000");
priceMap.put("pant", "100");
priceMap.put("harddisc", "3000");
// end of map
}
public static PriceCatalog getCatalog()
{
return calalog;
}
public BillStatus getStatus(String key)
{
BillStatus status= new BillStatus();
if(key == null || priceMap.get(key)==null)
{
status.setItem("Sorry" + key + " Not found in Inventory!!");
status.setPrice("Not Applicable");
return status;
}
status.setItem(key.toUpperCase());
String price = priceMap.get(key) + " Rupees only.";
status.setPrice(price);
return status;
}
}
Please Dowload Code base from
https://github.com/shami83/MicroOrderService
and
https://github.com/shami83/BillingService
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