Route Existing Services via ZUUL without adding routing rule - spring-boot

I am trying to route existing services via Spring cloud Netflix Zuul.
I have an existing service available at below url,
http://localhost:3080/query-service/getquery/1
Out of the box, with zuul I can route to the service as below,
localhost:9000/queryservice-id/queryservice/getquery/1, with "queryservice-id" as the service-id of the service when it is registered in Service Registry. The zuul port is 9000.
I do not want to change the context path and service path information when accessing the service via ZUUL.
With ZUUL, I want to access the service as below,
http://localhost:9000/query-service/getquery/1
I do want to prefix with the "serviceId". This is because I do not want to impact any existing clients of the service. Only the host and port changes, without serviceId.
I was able to accomplish it as below with ZUUL Configuration,
zuul:
routes:
query-service:
path: /query-service/**
serviceId: query-service
stripPrefix: false
With the above configuration, I am able to only use the zuul host and port, the other service specific information remains as before. Seems like stripPrefix is helping in routing without the serviceId.
But, I have a lot of services and will be adding more services too.
For every such service, I do not want to be adding a rule like that to ZUUL configuration which will mean rebuilding and recycling the ZUUL Service.
I feel there should be a simpler and better way to accomplish this, without a big effort, because the change I want to do is common to all services
Is there a way to making this change common for alll the services I want
to be routed via ZUUL.
Thanks,

As checked with the Spring Cloud Netflix team this is recommended approach.
https://github.com/spring-cloud/spring-cloud-netflix/issues/1549

Related

How to detect new REST calls dynamically as and when they are available?

I am creating an API gateway using Netflix Zuul and Netflix Eureka doing the part of service registration for service discovery for a microservices framework.
I am trying to support a use case where new micro-services may come up which expose REST calls, or existing micro-services may get upgraded to expose new REST calls with version as part of their URL etc. Eureka runs as a dedicated springboot application and Zuul runs as a dedicated application. The application.prop or application.yml file of Zuul is where i am putting config for zuul.routes for each micro-services
My zuul's application.yml looks something like this to support one microservice config.
zuul:
routes:
example:
path: /example/**
stripPrefix: false
serviceId: zuul-service
If i bring down zuul add another such snippet of config under zuul:routes:
and then bring up zuul again, i will start seeing the new endpoint. But i want that to happen dynamically. Like Eureka will dynamically detect any new micro-services that come up or go down. If zuul can get in sync with Eureka then all my rest endpoints can be exposed perfectly through my Zuul api gateway.
Any suggestions on what i may be missing or add any other open source third party to achieve this will be helpful.

routing differences through zuul proxy with eureka

I have two machines (with same application) register to eureka server.
all requests to these services are through zuul proxy.
my application.properties of my backend services is:
spring.application.name=core
my application.properties of my zuul proxy is:
zuul.sensitiveHeaders=Set-Cookie
zuul.routes.address.path=/to-address/**
zuul.routes.address.url=http://localhost:8888
zuul.routes.service.path=/by-service/**
zuul.routes.service.url=CORE
I have two questions:
All three request below are working, which one should I use?
What is the difference with upper case and lower case?
http://localhost:9090/api/by-service/customer/1
http://localhost:9090/api/core/customer/1
http://localhost:9090/api/CORE/customer/1
When I call the service in the following way:
http://localhost:9090/api/to-address/customer/1
I noticed that a new session is being created by my core server, which force my user to login again. Any idea why?
As you can see it's the same method (same filter, same application...) with just a routing difference.
you need to use req.getRequestedSessionId() instead of req.getSession().getId().

Zuul proxy that discovers routes dynamically

I have a simple Zuul app that has a single route in the application.yml to route to my microservice. It's working.
However, what I'm looking for is a more dynamic solution where I can wire up routes dynamically, either through code or perhaps by POSTing to some Zuul endpoints during a build (possibly by using springfox and a swagger definition from microservices). I could not find an API for Zuul.
I'm somewhat aware of Eureka and that seems like a solution to abstract away the routing by doing discovery. However, I'm curious if there's a solution without introducing Eureka. If there's a way to wire up these routes in Zuul during a build vs. having to edit the application.yml every time.
Thanks in advance.
If you go for Eureka this will actually work ootb. Zuul as packaged in spring cloud will automatically expose every service using its name. So if you register a service called users in Eureka, Zuul will automatically create a route /users forwarding to the instances by default. That will only allow simple url structures but should solve your problem.
Please see the official documentation for details:
By convention, a service with the ID "users", will receive requests from the proxy located at /users (with the prefix stripped). The proxy uses Ribbon to locate an instance to forward to via discovery, and all requests are executed in a hystrix command, …
I'm actually editing a blog post about this exact topic (Routing and Filtering using Spring Cloud Zuul Server) but the source code has been available and working for some time now. Feel free to use it as a reference:
https://bitbucket.org/asimio/zuulserver
https://bitbucket.org/asimio/discoveryserver (in case routes are configured with serviceIds)
https://bitbucket.org/asimio/demo-config-properties/src (Zuul-Server-refreshable.yml where routes are dynamically updated).
Look at the refreshable Spring profile settings. This Zuul setup works with both, hard-coding routes url or discovered using Eureka.
It also acting as a Spring Cloud Config client so that routes could be dynamically updated via Git, which is also covered in another blog post: Refreshable Configuration using Spring Cloud Config Server, Spring Cloud Bus, RabbitMQ and Git.

Spring Cloud Zuul: how to add route without restart

I am writing microservices with Spring Cloud.
I'm also using Zuul as the API Gateway which routes some URLs to destination services which are not registered into Eureka.
When a new route needed to be added to Zuul, we often edit the application.yml file and then restart the Zuul server.
I was wondering is there a way to add new route into Zuul without restarting the Zuul server?
I found this link useful but it only works for services registed in Erueka.

When to configure zuul routes

I am new to spring cloud and going through some examples and material available online to make myself comfortable. However, while reading about ZUUL, some sites configured the routes in ZUUL's application.yml and some other sites mentioned that the requests will be forwarded to the respective microservice and no need to explicitly configure the routes. I was bit confused. For ex, in the below scenario what is the approach, to configure routes or to let zuul route automatically?
Let's say i have few micro services running and all of them along with ZUUL are registered to Eureka.
I have a front end which is running on a different port on the same server and needs to interact with the above micro services.
I also have few other applications (Running entirely on different servers) which need to interact with the above micro services for fetching the data.
TIA..
Did you use Zuul (which know microservices address through Eureka) to forward request between your micro-services ? if it's the case, you are using Server-Side Load Balancing pattern.
If you use a discovery service (Eureka in your case), i think the best approach it's to use Client-Side load balancing pattern for all inter-services requests (inside your system). (you can use Ribbon or RestTemplate for that).
You can use Zuul as a unified front door to your system, which allows a browser, mobile app or other user interface to consume services from multiple hosts without managing cross-origin resource sharing (CORS) and authentication for each one.
For example : a client (mobile app) request for all picture comments. The client dont need to know the Comments-service address. Only proxy address needed and Zuul will forward the request to the right service. You can do this in application.yml/.properties by
zuul.routes.comments.path=/comments/**
zuul.routes.comments.service-id=comments
The request will be GET www.myproxy.mycompany.com/comments. Dont forget the service name in your application.yml/.properties is very important (spring.application.name). It's the service-id in Zuul routes (which the same identifier in Eureka).
For some reason, your system need to request external services (as you mentionned in the 3th note). In this case, your external services are not a discovery client, Zuul can't look for the service-id from Eureka. you use routes as
zuul.routes.currencyprovider.path=/currencies/**
zuul.routes.currencyprovider.url=https://currencies.net/
with this route, all /currencies/** requests from your services THROUGH Zuul will be done.
with this approach you have one door for all your system. This is API Gateway pattern.
Sometimes your system need to aggregate multiple results from different services to response to client request. You can do this in Proxy (Zuul in your case).

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