enable caching

.travis.yml

@@ -4,6 +4,11 @@ language: nix
 git:
   submodules: false
 
+# Cache the nix store (See https://nixos.wiki/wiki/Nix_on_Travis)
+cache:
+  directories:
+  - $HOME/nix.store
+
 branches:
   only:
   - master
@@ -12,6 +17,9 @@ notifications:
   slack:
     secure: 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
 before_install:
+- sudo mkdir -p /etc/nix
+- echo "substituters = https://cache.nixos.org/ file://$HOME/nix.store" | sudo tee -a /etc/nix/nix.conf > /dev/null
+- echo 'require-sigs = false' | sudo tee -a /etc/nix/nix.conf > /dev/null
 - openssl aes-256-cbc -K $encrypted_6059a4f451fd_key -iv $encrypted_6059a4f451fd_iv
   -in id_rsa.enc -out deploy_key -d
 - mv deploy_key ~/.ssh/id_rsa
@@ -25,3 +33,6 @@ script:
 after_success:
 - chmod +x ./deploy.sh
 - nix-shell --run './deploy.sh'
+before_cache:
+- mkdir -p $HOME/nix.store
+- nix copy --to file://$HOME/nix.store -f default.nix buildInputs