.gitlab-ci.yml

image: nixpkgs/cachix-flakes:nixos-20.03

build:
  before_script:
    - mkdir -p /etc/nix
    - echo "experimental-features = nix-command flakes ca-references recursive-nix" >> /etc/nix/nix.conf
    - cachix use numtide
    - nix path-info --all > /tmp/store-path-pre-build
  script:
    - nix flake check
  after_script:
    - nix develop -c ./cachix-upload.sh /tmp/store-path-pre-build

cachix-upload.sh

#!/usr/bin/env bash
set -euo pipefail

echo "Pushing paths"
comm -13 \
  <(sort "$1" | grep -v '\.drv$') \
  <(nix path-info --all | grep -v '\.drv$' | sort) \
  | cachix push numtide

echo "Pushing flake archives"
nix flake archive --json \
  | jq -r '.path,(.inputs|to_entries[].value.path)' \
  | cachix push numtide