How to serve Redis key with Nginx?

Question

I have all my JSON files located in Redis cache.

I want to get it served through Nginx.

    # redis-cli -h redis-master
    redis-master:6379> get "zips/80202.json"
       "{\"zipCode\":\"80202\",\"City\":\"DENVER\",\"StateCode\":\"CO\"}"

I would like to request the url to be like,

http://nginx-host/zips/80202.json

where nginx-host and redis-master are the services in Kubernetes.

expecting response with,

{"zipCode":"80202","City":"DENVER","StateCode":"CO"}

I am not finding a clear idea on how to configure Nginx. I am running with Kubernetes containers, so services are local with no authentication required to the Redis servers.

Kannaiyan · Accepted Answer · 2021-06-07T16:20:15.353

Here is the nginx configuration used to serve with redis key,

resolver local=on ipv6=off;

server {
    listen 9000;

    location / {

        set $target '';
        access_by_lua '
            local key = ngx.var.request_uri
            if not key then
                ngx.log(ngx.ERR, "no key requested")
                return ngx.exit(400)
            end

            local redis = require "resty.redis"
            local red = redis:new()

            red:set_timeout(1000) -- 1 second

            local ok, err = red:connect("redis-master.default.svc.cluster.local", 6379)
            if not ok then
                ngx.log(ngx.ERR, "failed to connect to redis: ", err)
                return ngx.exit(500)
            end

            local value, err = red:get(key)

            if not value then
                ngx.log(ngx.ERR, "failed to get redis key: ", err)
                ngx.status = 500
                ngx.say("Something not right")
                return ngx.exit(ngx.OK)
            end

            if value == ngx.null then
                ngx.log(ngx.ERR, "no host found for key ", key)
                ngx.status = 404
                ngx.say("Not found")
                return ngx.exit(ngx.OK)
            end

            if value then
                ngx.say(value)
                return
            end

            ngx.var.target = http
        ';

        
    }
}

score 0 · Answer 2 · answered Jun 02 '21 at 03:08

0

To serve redis data (key:value) pairs via Nginx, you will need the following:

A redis client, for instance, https://github.com/NodeRedis/node-redis. This client will help retrieve data from redis. You will have to NodeJs Express to give you the API layer
You will have to create a service, which will have to be exposed via the ingress controller (if you want to access it from outside your K8s cluster
Nginx ingress controller configuration to route the requests to this service

answered Jun 02 '21 at 03:08

Rakesh Gupta

3,507
3
18
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nginx has a module to integrate with redis, no need to do any layer of code to pull data from redis. https://www.nginx.com/resources/wiki/modules/redis2/ . I have tried few different configuration and they don't work. – Kannaiyan Jun 02 '21 at 03:10
looks like json conversion is a To-do item for redis2 project. – Rakesh Gupta Jun 02 '21 at 03:30
Over http all responses you send will go as a stream / string, not as json objects. Based on the content type, the client converts the data to their respective object. http itself is content agnostic. – Kannaiyan Jun 02 '21 at 03:44

How to serve Redis key with Nginx?

2 Answers2