I need help on following:
I want to use RabbitMQ message broker for internal communication among microservices. For example shopping cart, order, product, payment etc.
Can I use AMQP for internal communication among microservices &
MQTT for push notification to mobile & web browser?
Can I use both AMQP & MQTT with RabbitMQ at the same time or only one can be used not both?
Related
I want develop a project in microservice structure.
I have to use php/laravel and nodejs/nestjs
What is the best connection method between my microservices. I read about RabbitMQ and NATS messaging
and also GRPC
Which option is more suitable for microservice?
and why?
Thanks in advance
The technologies address different needs.
gRPC is a mechanism by which a client invokes methods on remote (although they needn't be) server. The client is tightly-coupled (often through load-balancers) with servers that implement the methods.
E.g. I (client) call Starbucks (service) and order (method) a coffee.
gRPC is an alternative to REST, GraphQL, and other mechanisms used to connect clients with servers though some form of API.
Message brokers (e g NATS, Rabbit) provide a higher-level abstraction in which a client sends messages to an intermediate service called a broker (this could be done using gRPC) and the broker may queue messages and either ship them directly to services (push) or wait for a service to check its subscription (pull).
E.g. I (client) post a classified ad on some site (broker). Multiple people may see my ad (subscriber) and offer to buy (method) the items from me. Some software robot may subscribe too and contact me offering to transport or insure the things I'm selling. Someone else may be monitoring sales of widgets on the site in order to determine whether there's a market for opening a store to sell these widgets etc.
With the broker, the client may never know which servers implement the functionality (and vice versa). This is a loosely-coupled mechanism in which services may be added and removed independently of the client.
If you need a synchronous response on 1:1 service call use gRPC
If you don't care which service will consume messages (asynchronous & no tight coupling between services) use RabbitMQ
If you need distributed system to keep events history and reuse later on another service use Kafka
Basically, it comes down to whether you want an Async communication between services or not.
That is when you can decide between real-time communication services (Sync) such as gRPC or RPC & Message Queueing ones (Async) such as RabbitMQ, Kafka or Amazon SQS.
Here are also some good answers by other users:
https://dev.to/hypedvibe_7/what-is-the-purpose-of-using-grpc-and-rabbitmq-in-microservices-c4i#comment-1d43
https://stackoverflow.com/a/63420930/9403963
As I have previously mentioned, I am using ServiceStack Messaging API (IMessageQueueClient.Publish) as well as the more low-level IRedisClient.PublishMessage.
I use the Messaging API when I need a specific message/request to be processed by only one instance of a module/service, so even though I might have several modules running that all listens for MyRequest, only one service receives the message and processes it.
I use the IRedisClient.PublishMessage when I do a broadcast, a pub/sub situation, sending a request that everyone should receive that listens on that specific Redis channel.
However, I am in a situation where it would be useful to use the Messaging API, but do a broadcast, so that all instances that are listening to a specific message type, gets the message, not just the one.
(The reason for this is to streamline our usage of Redis and how we subscribe to events/request, but I will not get into details about this now. A little more background on this is here.)
Is there a "broadcast way" for the Messaging API?
No, the purpose of ServiceStack Messaging is simply to invoke ServiceStack Services via MQ. Any other MQ features is outside the purpose & scope of ServiceStack MQ, you'd need to instead develop against the MQ Provider APIs directly to access their broadcast features.
Server Events is a ServiceStack feature that supports broadcasting messages to subscribers of user-defined channels, but its a completely different implementation that serves a different use-case for sending "server push" real-time events over HTTP or gRPC, e.g. it doesn't use MQ brokers and pub/sub messages aren't persistent (i.e. only subscribers at time messages are sent will receive them).
I am a little bit confused about what extra functionality MQTT over WebSocket provides vs traditional MQTT over TCP in react native. Is MQTT over WebSocket a solution for browsers in order to receive an event in real-time or it adds something more that I can't catch?
MQTT over Websockets provides 2 main capabilities over native MQTT.
Allows browser based systems to connect to brokers and publish/subscribe to messages. This is because the browser's sandbox doesn't allow native socket operations.
Allows MQTT applications to make use of existing proxy set ups. MQTT over Websocket connections can be made through HTTP proxies in situations where other traffic is blocked by a local firewal.
I need to build a server and a client that can exchange data in real time with a company's proxy between them. No one has the authorisation to amend the proxy's configuration (in order to allow the WebSocket protocol).
I would need a fallback technology such as long-polling.
Example: client is a user's PC employee. He needs to exchange data with the server, located in the cloud and separated by company's proxy.
Ideally, I would use WebSocket with SSL, but I know some proxies are not configured for WebSocket messages and thus could reject the connection.
The app would therefore switch to another push technology such as long-polling, increasing the chances of getting a successful connection (is 100% guaranteed with proxies? Giving that there are several types of proxies...)
Are there any libraries/frameworks proposing such features?
Usually, secure WebSocket connections do fine through proxies.
In .NET you have SignalR
In node.js you have socket.io
I am looking at various options for a WCF based publish subscribe framework. Say I have one WCF web service that will be the publisher and 1000 clients registered as subscriber. For some published messages all clients will be interested but at the same time I wish the ability to notify a single client with a specific message. On receiving notification the client will call other web service methods on the web service.
Is NServiceBus suitable for this kind of scenario ?
If I use MSMQ for transport does it mean that every PC where the client is installed requires a queue to be created ?
Some of the challenges include how you want the publisher to behave when a given subscribing client is down - do you want that message to be available when the subscriber comes back up? If so, then some kind of durable messaging is needed between them - like MSMQ.
Your question about notifying a single client, is that as a result of a request sent by that client? If so, then standard NServiceBus calls in the form of Bus.Reply will do it for you. When using WCF, if the response is to be asynchronous you'll need to use callback contracts.
NServiceBus can do all the things you described, and has the ability to automatically install MSMQ and create queues so that greatly simplifies client-side deployments.
You also have the ability with NServiceBus to expose messages over WCF so you can support non-NServiceBus clients if you need to as well. It also has its own http gateway and XSD schemas which can allow clients on non-Windows platforms to interoperate even without using WCF.
Hope that answers your questions.