I'm learning redis and have it working from a java app. I'm trying to use the heroku redis:cli -a myAppName command to connect with it directly but it says "No Redis instances found".
When I do heroku apps it lists myAppName so I know it's valid.
heroku redis:info -a myAppName doesn't return anything.
The heroku docs don't seem to be accurate as they all leave out the -a flag which the cli tells me is required. Outside of that I don't know what I've missed.
You are looking at documentation for Heroku Redis, a hosted Redis service that Heroku itself provides. If you wish to use Heroku Redis, you can provision it for your app using like so:
heroku addons:create heroku-redis:hobby-dev -a your-app-name
Pricing for Heroku Redis can be found here. The Hobby Dev plan used in the previous command is free.
There are also other Redis providers that can be provisioned this way, including Redis Enterprise Cloud. Or you can use existing hosted Redis server. But with these options you won't be able to interact with the service using heroku redis commands. Use whatever tooling those providers offer.