Error when trying to build my Plutus project

Question

I am getting the following error after trying to execute cabal build:

cabal: Could not resolve dependencies:
[__0] next goal: cardano-crypto-class (user goal)
[__0] rejecting: cardano-crypto-class-2.0.0.0.1/installed-iw7NtuXmRKLDXiVT5sxh
(constraint from user target requires ==2.0.0)
[__0] rejecting: cardano-crypto-class-2.0.0 (conflict: pkg-config package
libsodium-any, not found in the pkg-config database)
[__0] fail (backjumping, conflict set: cardano-crypto-class)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: cardano-crypto-class

I am using cabal 3.6.2.0 and ghc 8.10.7

Answer 1

You are missing libsodium :

[__0] rejecting: cardano-crypto-class-2.0.0 (conflict: pkg-config package
libsodium-any, not found in the pkg-config database)

The way I get around this is sudo apt install libsodium-dev and then create a top level file cabal.project.local containing:

package cardano-crypto-praos
  flags: -external-libsodium-vrf

Pretty sure this is documented somewhere in the cardano-node repository.