bash script generate nix package hashes

nix-generate-hash.sh

#!/usr/bin/env bash

# First get version from the latest git tag
VERSION="$(git describe --tags --abbrev=0)"
NIX_FILE="nix/package.nix"

echo "Bumping version to $VERSION"
# replace  version = "local-2024-09-16"; within "$NIX_FILE"
sed -i "s/version = \".*\";/version = \"$VERSION\";/" "$NIX_FILE"
sed -i 's/sha256-.*=//g' "$NIX_FILE"
## nix build and pipe the error to a build.log file
rm -f build.log

nix build . 2> build.log

# format
#   specified: sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=
#   got:    sha256-crOHNrO4KkHn3kKGlwitirBpsgtAGXpDKBORmpVUKFs=
SHA256=$(grep "got:" build.log | grep -o "sha256-.*=" | cut -d'-' -f2)

echo "git hash SHA256: $SHA256"
sed -i "s# hash = \".*\";# hash = \"sha256-$SHA256\";#" "$NIX_FILE"
nix build . 2> build.log

SHA256=$(grep "got:" build.log | grep -o "sha256-.*=" | cut -d'-' -f2)
echo "cargo hash SHA256: $SHA256"
sed -i "s#cargoHash = \".*\";#cargoHash = \"sha256-$SHA256\";#" "$NIX_FILE"

echo "Building nix derivation"
nix build .

rm -f build.log