I'm trying Redis for my project backend that rely on cloud functions with HTTP trigger and Express routing and I have connection leak because Redis client is not disconnected when the function finished. I'm going to use cloud run for microservices in the future so I think it might have same problem so I decided to ask first.
I tried process.on("exit", ()=> {}); but it won't work.
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Consider a small chat server. In this server, the actual processing of messages is done by nodes of a service called "chat". Communications of this service along with a "user" service are then aggregated via a "gateway" service in front that is the only service that actually communicates with the users and is in charge of passing requests received to other services via the RabbitMQ channel they share.
In a system designed like this, each user is connected to one of the instances of the "gateway" service and when sending and receiving messages indirectly communicates with the private "chat" or "user" services behind. To load balance this, we have an Nginx reverse-proxy on the edge that tries to distribute requests to different "gateway" instances. But since WebSocket connection is real-time, "chat" instances should also be able to send messages to the right instance of the "gateway" in charge of that specific user for user-specific messages and to all "gateway" instances for site-wide messages. This is a problem since with RabbitMQ I don't believe we can target a specific subscriber and even if we could, we don't know to which instance that specific user is connected right now.
Therefore, since we are using Socket.io for WebSocket connection, I am thinking of adding a new Redis node to the stack to allow this communication between different instances of the "gateway" service. This is directly supported by Socket.io and works alright and removes all sorts of limitations imposed by the RabbitMQ, however, we are still using RabbitMQ to route a message from a "chat" instance to a "gateway" instance that then will propagate through the Redis service and when the right "gateway" instance having access to the user is found, delivered to them.
This adds unnecessary lag to user-specific outbound messages. So here I am asking if anyone has a better idea of how this problem should be approached and how to decrease this lag.
Personally, I have this idea of adding Socket.io to "chat" services (with no client access) and use its backend to send the message directly to the Redis store so that the instance of the "gateway" connected to it can route it directly to the user, going over the whole RabbitMQ thing for this type of messages.
It might be important to mention that none of these services are here just to do this specific thing, RabbitMQ is heavily used for communication between different services acting as the message broker and the "gateway" service works with multiple other services for data aggregation, authentication and data validation and transformation. The above example was a simplified version of the problem at hand with the minimum number of moving parts that I could easily describe here.
Edit: To send messages directly to socket.io redis store, the following library can be used apparently not to load the whole socket.io library:
https://github.com/socketio/socket.io-redis-emitter
I'm using azure redis cache for certain performance monitoring services. Basically when events like page loads, etc occur, I send a fire and forget command to redis to record the event. My goal is for my app to function fine whether or not it can contact the redis server. I'm looking for a best practice for this scenario. I would be OK with losing some events if necessary. I've been finding that even though I'm using fire and forget, the app staggers when the web server runs into high latency or connectivity issues with the server.
I'm using StackExchange.Redis. Any best practice configuration options/programming practices for this scenario?
The way I was implementing a singleton pattern on the connection turned out to be blocking requests. Once I fixed this my app behaves as I want (e.g. it still functions when redis connection dies).
I am looking at integrating a caching service with serverless.
I have decided to go with redis. However through reading through the npm redis, it seems that you are required to call client.quit() after completing the request.
The way serverless seems to work is that the instance is spawned, and then deleted when not in use. So I was wondering if there was a way to quit the redis connection when the serverless instance is being deleted.
Or whether I just have to actually just start a connection on every request, and quit the connection before each request finishes.
I was hoping I could do it on the app state, instead of request state, that way I wont have to spawn so many connections.
No. A connection could be reused. It does not need to start a new connection on every request.
If you use the redis.creatClient() to create a connection, you could use this connection always in your app. And it has reconnect mechanism if the connection is broken. So in your app development, you do not need to care the connection problem, just get a global connection and always use it.
I am totally new to spring framework. I am trying to create a project where I can have the connectivity to the rabbitMq and I even before I publish the message, I want to check if the queues are alive or not. Is this possible to ping the queue to see if it is alive or not?
RabbitMQ have the management API. You can use it to check the status of queue,exchange,binding.
If you are working on PHP. Then here is the libarary which can be used.
I am new to cloud foundry and investigating possible ways for our legacy Java EE application to communicate asynchronously with an application running on cloud foundry.
We are doing a lot of asynchronous work already and are publishing events to Active MQ.
I know that cloud foundry has a possibility to bind with Rabbit MQ and my question is with the possibility for a cloud foundry running application to connect (listen) to an existing out of CF platform Rabbit MQ?
Any idea on other alternatives to achieve this?
Yes, that is possible. You can use a user provided service.
That allows you to inject the environment variables into your app, that are needed to connect to RabbitMQ (like host, port, vhost, username, password).
Once you create that service, you can bind it to your app. Inside your app code, you then can read the environment variables exactly the same way as you would do it, if you had used a RabbitMQ service provided by CloudFoundry.