SRH: Serverless Redis HTTP

TLDR: If you want to run a local Upstash-compatible HTTP layer in front of your Redis:

Have a locally running Redis instance - in this example bound to the default port 6379
create a json file called tokens.json in a folder called srh-config (srh-config/tokens.json)
paste this in:

{
  "example_token": {
      "srh_id": "some_unique_identifier",
      "connection_string": "redis://localhost:6379",
      "max_connections": 3
  } 
}

Run this command: docker run -it -d -p 8079:80 --name srh --mount type=bind,source=$(pwd)/srh-config/tokens.json,target=/app/srh-config/tokens.json hiett/serverless-redis-http:latest
Set this as your Upstash configuration

import {Redis} from '@upstash/redis';

export const redis = new Redis({
    url: "http://localhost:8079",
    token: "example_token",
});

A Redis connection pooler for serverless applications. This allows your serverless functions to talk to Redis via HTTP, while also not having to worry about the Redis max connection limits.

The idea is you host this alongside your Redis server, to minimise latency. Your serverless functions can then talk to this via HTTP.

Features

Allows you to talk to redis via HTTP
Pools redis connections
Automatically kills redis connections after inactivity
Supports multiple redis instances, and you can configure unique tokens for each
Fully supports the @upstash/redis TypeScript library.
Works inside of GitHub Action's services, so you can run it alongside Redis in your tests.

Client usage

This will not work with regular Redis clients, as it is over HTTP and not the redis protocol. However, to try and keep the project as "standardised" as possible, you can use the @upstash/redis TypeScript library. You can read about it here: Upstash Redis GitHub

Soon I will add specific documentation for the endpoints so you can implement clients in other languages.

Installation

You have to options to run this:

Via docker: docker pull hiett/serverless-redis-http:latest Docker Hub link
Via elixir: (clone this repo) -> mix deps.get -> iex -S mix

If you are running via Docker, you will need to mount the configuration file to /app/srh-config/tokens.json.
An example of a run command is the following:

docker run -it -d -p 8080:80 --name srh --mount type=bind,source=$(pwd)/srh-config/tokens.json,target=/app/srh-config/tokens.json hiett/serverless-redis-http:latest

Note that it is running on port 80

To configure Redis targets:
Create a file: srh-config/tokens.json

{
    "example_token": {
        "srh_id": "some_unique_identifier",
        "connection_string": "redis://localhost:6379",
        "max_connections": 3
    } 
}

Alternatively, if you are connecting to just one Redis server, you can use environment variables to set the target.

SRH_MODE="env"
SRH_TOKEN="example_token"
SRH_CONNECTION_STRING="redis://redis:6379"

If you use this strategy, it's important that you set SRH_MODE=env. This is because SRH by default uses the file strategy for backwards-compatability.

Docker Compose

You'll want the above tokens.json file but use this as your connection string:

"connection_string": "redis://redis:6379"

docker-compose.yaml

version: '3'
services:
  redis:
    image: redis
    ports:
      - '6379:6379'
  serverless-redis-http:
    ports:
      - '8079:80'
    image: hiett/serverless-redis-http:latest
    volumes:
      - ./path/to/tokens.json:/app/srh-config/tokens.json

Notes:

Srh_id can be anything you want, as long as it's a string, and unique.
max_connections is the maximum number of connections for the pool.
- If there is inactivity, the pool will kill these connections. They will only be open while the pool is alive. The pool will re-create these connections when commands come in.
You can add more redis instances to connect to by adding more tokens and connection configurations. Based on the header in each request, the correct pool/connection info will be used.