Service Registry Pattern — Netflix Eureka Server With Steeltoe & .NetCore & PCF

5 min readMar 6, 2021

Service Registry provides your apps with an implementation of the Service Discovery pattern, one of the key tenets of a microservice-based architecture. Trying to hand-configure each client of a service or adopt some form of access convention can be difficult and prove to be brittle in production. Instead, your apps can use the Service Registry to dynamically discover and call registered services.

When a client registers with the Service Registry, it provides metadata about itself, such as its host and port. The Registry expects a regular heartbeat message from each service instance. If an instance begins to consistently fail to send the heartbeat, the Service Registry will remove the instance from its registry.

Why Service Registry:

In microservices architecture patterns we have lot of microservices in place from different sources (i.e. Different Hostnames & dynamic ports). To manages those service contracts is very difficult. To overcome this problem service registry come into picture.

Use Case:

Prerequisites:
1. PCF account (i.e. PCF part of VMware Tanzu https://login.run.pivotal.io/login It may differ )
2. CF CLI Installation(i.e. https://docs.run.pivotal.io/cf-cli/install-go-cli.html ) Windows Platform choice.
3. .Net 5 with Blazor Framework (i.e. we can choose lower versions also )
4. steeltoe Packages from NuGet
5. Within PCF we need Service Registry service in marketplace.
6. Create a .net core supported version of build packs with in PCF.

Step 1:

Install CF CLI on your windows ENV (i.e. https://docs.pivotal.io/pivotalcf/2-3/cf-cli/install-go-cli.html ) & set path for CF CLI. Login to CF CLI through CMD by using your PCF account API (i.e. go to Tools option in your PCF ENV). After login choose your org & space.

Step 2:
Create a Service Registry service within your space by using CF CLI like below
( i.e. https://docs.pivotal.io/spring-cloud-services/3-1/common/service-registry/managing-service-instances.html )

cf create-service p.service-registry standard myDiscoveryService ( i.e. Spring Cloud Services)

cf create-service p-service-registry standard myDiscoveryService  // According to steeltoe Doc

Step 3:
Create a Sample web api project (i.e. M_Service1) by using Visual studio like below.

Add below NuGet packages.

Update Program.cs file like below.

Add sample method in WeatherForecastController.cs

Add manifest.yml file into M_Service1 Web API project and update file according to your PCF deployment. Here very basic level configuration on PCF env deployment like below. myDiscoveryService service will bind the Micro_Service_1 application after deploying into PCF.

Update the appsettings.Development.json file like below

we can set “ShouldFetchRegistry”: false bcz we’re registering M_Service1 API into Eureka server. EurekaServerServiceUrls automatically updated with bound the service URL with help of steeltoe lib’s after deployment into PCF env.
For more Eureka config settings refer following link https://docs.steeltoe.io/api/v3/discovery/netflix-eureka.html

Step 4:

Publish the M_Service1 API into PCF by using CF CLI . If you’re using CI/CD pipeline means we need to configure according to pipeline rules.

For now we can deploy through manual by using CF CLI.
a. Publish M_Service1 API into any local directory (i.e. C:\MS1\). Make sure manifest.yml should be in published location.
b. Login CF CLI & select corresponding Space with help of CMD.
c. After login into PCF navigate to published location within same CMD CF CLI login session (i.e. cd C:\MS1 )
d. After navigated into published location M_Service1 API then type cf push
e. You’re able to see deployment completed status logs of PCF in CMD.

Step 5:
Login into you’re PCF account you’re able see your deployed app within DEV space.

Go to Micro_Service_1 App you’re able see dashboard like below & Go to Service option. In service option page you’re able to see you’re registered service app.