How to actually setup the Python Component

[TheGlobalist]

Hi, I have a question regarding the setup of my client as I can't really understand what actions do I need to take from the README.md.

I have an Eureka project with the following application.properties

spring.application.name=eureka-service
server.port= 8761
eureka.server.wait-time-in-ms-when-sync-empty=0

eureka.client.register-with-eureka=true
eureka.client.fetch-registry=false

Next, I wanted to attach Zuul Gateway, in order to have a sort of API Gateway. It gets registered without any problem with the following application.properties.

server:
  port: 8073

spring:
  application:
    name: zuul-gateway

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka

zuul:
  ignoredPatterns:
    - /authenticate
    - /delete
    - /refresh
  routes:
    user-service:
      path: /us/**
      url: http://localhost:5000/
      stripPrefix: true

Now comes my problem. I'm trying to register to Eureka (and, then, make it discoverable and callable also from Zuul) a really simple Flask Component, called user-service, defined with just the following lines

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello World!'

if __name__ == '__main__':
    import py_eureka_client.eureka_client as eureka_client

    your_rest_server_port = 5000
    # The flowing code will register your server to eureka server and also start to send heartbeat every 30 seconds
    eureka_client.init(eureka_server="http://localhost:8761",
                       app_name="user-service",
                       instance_port=your_rest_server_port)
    app.run()

When I run all the 3 projects, though, Eureka can't manage to find the user-service. Even if I try to use init_discovery_client, I'm still getting the same issue.

Could anyone help me on this?

[dinuta]

Hi @TheGlobalist,

Check an exemple of mine in estuary-discovery or estuary-testrunner.

From what i see the registration link is incorrect.

There are two forms for the eureka server url, from what i recall. One that i am using is something like: http://localhost:8761/eureka/v2

Keep me posted if you succeed. And you will!

[dinuta]

Class: https://github.com/dinuta/estuary-testrunner/blob/master/rest/api/eureka_registrator.py

Register call (from the service):

EurekaRegistrator(os.environ.get('EUREKA_SERVER')).register_app(os.environ["APP_IP_PORT"])

And the service boot options via env vars:

docker run \
-e EUREKA_SERVER=http://10.10.15.28:8080/eureka/v2 
-e APP_IP_PORT=10.10.15.28:8081
-p 8080:8080
dinutac/estuary-testrunner:latest

Also you have a tested and updated dockerized eureka server here: https://github.com/dinuta/netflixoss-eureka

[TheGlobalist]

CHanging the call to

    eureka_client.init(eureka_server="http://192.168.1.10:8761/eureka/",
                       app_name="user-service",
                       instance_port=your_rest_server_port,
                       instance_ip="http://127.0.0.1")

Or

    eureka_client.init(eureka_server="http://localhost:8761/eureka/v2/",
                       app_name="user-service",
                       instance_port=your_rest_server_port,
                       instance_ip="http://127.0.0.1")

Still doesn't help :(

[dinuta]

Change to:

eureka_client.init(eureka_server="http://localhost:8761/eureka/v2/",
                       app_name="user-service",
                       instance_port=5000,
                       instance_ip="127.0.0.1")

or

eureka_client.init(eureka_server="http://localhost:8761/eureka/",
                       app_name="user-service",
                       instance_port=5000, 
                       instance_ip="127.0.0.1")

Instance_ip is either the ip (i recommend to put the network ip, and not localhost) or full hostname.

[TheGlobalist]

Tried both of configurations but still Eureka won't see the Flask Component :(

[dinuta]

This requires complex debugging. You can try 2 scenarios:

• register one of my flask services to your eureka
• register your sample flask to my eureka which is dockerized

Furthermore you can write a small client to fetch Information from eureka to see you are able to retrive the info.

[TheGlobalist]

Apparently, using it from PyCharm is the problem: if I run my snippet through iPython, Eureka sees my component

[keijack]

Hi, @TheGlobalist, After started your flask program, did you find any logs in it? What's the result if you visit http://localhost:8761/eureka/v2/ in your browser?

[TheGlobalist]

Hi, @TheGlobalist, After started your flask program, did you find any logs in it? What's the result if you visit http://localhost:8761/eureka/v2/ in your browser?

Hi, Sorry for being super late in responding! I've swapped configurations: now I'm using a Sanic Web Server to deploy my app. The initialization is done in the following way on my Python Microservice

from helpers.helper import create_app, run_app
from controllers import usercontroller, regtokenutentecontroller, mailcontroller

sanic_app = create_app(
    blueprints=((usercontroller.bp, regtokenutentecontroller.bp, mailcontroller.bp))
)

if __name__ == "__main__":  # pragma: no cover
    run_app(sanic_app)
    import py_eureka_client.eureka_client as eureka_client

    # The flowing code will register your server to eureka server and also start to send heartbeat every 30 seconds
    eureka_client.init(eureka_server="http://localhost:8761/eureka/",
                       app_name="user-service",
                       instance_port=8071)

Which outputs the following

bin/python /Users/gimmi/Desktop/Università/MAGISTRALE/TESI/DataEX/MicroServizi/UserService/user-service/sanic_starter.py
[2020-06-07 14:29:33 +0200] [11133] [INFO] Goin' Fast @ http://localhost:8071
ciao
[2020-06-07 14:29:33 +0200] [11133] [INFO] Starting worker [11133]

But that's it. Nothing more.

Eureka just outputs the following

2020-06-07 14:29:30.646  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 2ms

2020-06-07 14:30:30.648  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 1ms

2020-06-07 14:31:30.648  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 0ms
2020-06-07 14:32:30.650  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 2ms
2020-06-07 14:33:30.652  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 1ms
2020-06-07 14:34:30.656  INFO [,,,] 1048 --- [a-EvictionTimer] c.n.e.registry.AbstractInstanceRegistry  : Running the evict task with compensationTime 3ms

and register the microservice only when I shut it down from PyCharm. If I go to http://localhost:8761, which exposes Eureka, I only see the API Gateway that I'm using (which is Zuul)

[keijack]

as well as run_app(sanic_app) is a blocked method, I think you should place it at the end of the method (after eureka_client.init).