Plutus Playground Server error: opening lock file '/nix/...root.lock': Permission denied

Question

So I've been going through the Plutus Pioneers 3rd cohort lectures and last night accidentally left my computer unplugged. When I booted up Ubuntu Linux on the computer this morning I noticed I have 3 copies of plutus-apps folders on my computer and I only use one for going in nix-shell and running plutus playground so I deleted the other 2.

I went to set up Plutus-Playground-Server for a new lecture and went through the steps here to get everything set back up again (which have worked fine before since I've set it all up already).

https://plutus-community.readthedocs.io/en/latest/#Plutus/Build/Ubuntu/

In terminal window 1

cd plutus-apps
nix-shell
cd plutus-playground-server
plutus-playground-server

However, I am getting these errors (tried sudo plutus-playground-server as well, didn't work).

I thought maybe there's something that needs updating so I updated all my apps. I noticed my Nix is running on 2.8.1 and now there is 2.10

https://nixos.org/download.html

Tried several ways of updating nix including the methods given in the link, I keep getting these similar permission denied messages. Sudo doesn't work in this instance.

[nix-shell:~/plutus-apps/plutus-playground-client]$ GC_DONT_GC=1 plutus-playground-server
plutus-playground-server: for development use only
error: opening lock file '/nix/store/69h1ik7v55mi947xfn28bwxkvn2fn4z9-plutus-apps-root-plutus-ledger-constraints-lib-plutus-ledger-constraints-root.lock': Permission denied
(use '--show-trace' to show detailed location information)
error: opening lock file '/nix/store/69h1ik7v55mi947xfn28bwxkvn2fn4z9-plutus-apps-root-plutus-ledger-constraints-lib-plutus-ledger-constraints-root.lock': Permission denied
(use '--show-trace' to show detailed location information)
/nix/store/fm77y43lzpgnay4pyc48jwpln0lnmrk3-plutus-playground-server/bin/plutus-playground-server: line 10: /bin/plutus-playground-server: No such file or directory

Just to try everything I tried changing git versions of plutus-apps like you need to do as you go through plutus cohort #3. I did git checkout for different weeks of the plutus pioneer program and i'm getting:

fatal: reference is not a tree

However, the git checkout in plutus-community docs works just fine (but plutus playground server still doesn't work).

https://plutus-community.readthedocs.io/en/latest/#Guides/BuildCabalBuild/

I have restarted my computer as per this link, still getting the same errors.

/bin/plutus-playground-server: No such file or directory

Is this having to do with the new cardano node 1.35.3 and the Vasil upgrade or just a bonehead move on my part? Any help is appreciated, thanks!

Answer 1

Went back and tried getting it to work today, first went to this link https://www.punkbit.com/hacking/plutus-developer-environment-setup-on-macos-monterey/#6-run-the-plutus-playground-service-and-frontend

and added in my nix.conf file

build-users-group = nixbld

the playground server still wasn't working so I found someone having a similar github issue with Nix here

https://github.com/NixOS/nix/issues/4356

sudo chown -R "Your User Account Name":staff /nix

afterwards plutus-playground-server worked, no extra GC_DONT_GC=1 needed in my case.

This makes sense because I was getting logged permission errors from nix and this command gives me ownership of nix folder and subdirectories.

2nd terminal with

cd plutus-apps
nix-shell
cd plutus-playground-client
npm run start

is working fine, the plutus playground server is running for me.