Delegate Service

This service communicates with other Delegate services running in multiple Nimble clusters, collects the responses from the other services and returns back a single response which consists of an array of per-cluster response.

On startup, the service registers with the Eureka server and then it uses the Eureka client to dynamically get the list of the other Delegate services running in multiple Nimble clusters.

On shutdown, the service un-registers from the Eureka server.

APIs

The following list specifies the APIs which are supported by the service:

/serve?local=0 returns a single response which is a collection of all the responses from all the Nimble clusters.
/serve?local=1 returns a local response which is a response of the local Delegate service ONLY (without calling the Delegate services in the other Nimble clusters).
/eureka returns a list of all the Delegate services registered in the Eureka server (used for debug).

Running the service on a single machine using Docker

Preqrequisites

Build

$ git clone git@github.com:nimble-platform/delegate-service.git
$ cd delegate-service
$ mvn compile
$ mvn package
$ docker build -t nimble-delegate .

Configuration

The Eureka server URL is defined by the eureka.serviceUrl.default parameter in the eureka-client.properties file. The default value is http://eureka:8080/eureka/v2/.
The Eureka vipAddress of the Delegate Service is defined by the eureka.vipAddress parameter in the eureka-client.properties file and by the context-param parameter in the web.xml file. The value must be the same.
The URL path of the main service API (/serve) is defined by the context-param parameter int the web.xml file. The default value is /serve.

Create a docker network

$ docker network create nimble

This nimble network is used to connect all the docker containers

Run the Eureka server

$ docker run -d --name eureka --net nimble -p 8080:8080 netflixoss/eureka:1.3.1

Once the Eureka server is running, you can access the Dashboard using the Dashboard URL

Run the Delegate Services

$ docker run -d -p 8881:8080 --net nimble --name delegate-1 nimble-delegate 
$ docker run -d -p 8882:8080 --net nimble --name delegate-2 nimble-delegate 
$ docker run -d -p 8883:8080 --net nimble --name delegate-3 nimble-delegate

Access the Delegate service

$ curl localhost:8881/serve?local=0

You should receive a single JSON response which consists of an array of multiple responses (one from each Delegate service)

Stop the Delegate Services

$ docker stop delegate-1 delegate-2 delegate-3

Note: it is better to stop the services before removing them, to let them un-register gracefully from the Eureka server. If you remove the service by using (docker rm -f) it will take about 30 seconds (hearbeat timeout period) until the service is removed from the Eureka Server.

Remove the Delegate Services

$ docker rm delegate-1 delegate-2 delegate-3

deploy the delegate service on Staging

follow these steps:

git clone delegate service project
go to the file src/main/resources/eureka-client.properties and change eureka.name=Staging and eureka.homePageUrl=nimble-staging.salzburgresearch.at
build the project using mvn and create a docker image locally with the following command: mvn compile ; mvn package ; docker build -t nimbleplatform/delegate-service:staging .
need to update docker-compose.yml and add these lines (under services):

  ###############################
  ###### Delegate Service #######
  ###############################

  delegate-service:
    image: nimbleplatform/delegate-service:staging
    env_file:
      - env_vars
    environment:
      - FRONTEND_URL=http://nimble-staging.salzburgresearch.at/frontend/
      - INDEXING_SERVICE_URL=nimble-staging.salzburgresearch.at/indexing-service
      - INDEXING_SERVICE_PORT=-1
    ports:
      - "9265:8080"
    networks:
      - infra

(you need to update the ips and port for the staging instance, port = -1 if you're using no port in case like nginx)
5. then in dev I ran the docker using ./run-dev.sh restart-single delegate-service, not sure how you do it in staging