[DEVOPS-779] simplify CI setup with buildkite hooks

.buildkite/hooks/pre-command

@@ -0,0 +1,22 @@
+set -x
+
+case $(uname -s | tr '[:upper:]' '[:lower:]') in
+        linux )  NIX_PROFILE_BINPATH=/run/current-system/sw/bin/;;
+        darwin ) NIX_PROFILE_BINPATH=/nix/var/nix/profiles/default/bin;;
+        * )      echo "Unsupported OS: $OS_NAME" >&2; exit 1;;
+esac
+
+# Bootstrap on OS X/NixOS:
+
+NIX_BUILD="$(type -P nix-build)"
+NIX_BUILD="${NIX_BUILD:-$NIX_PROFILE_BINPATH/nix-build}"
+NIX_SHELL="$(type -P nix-shell)"
+NIX_SHELL="${NIX_SHELL:-$NIX_PROFILE_BINPATH/nix-shell}"
+NIX_BUILD_SHELL="$(type -P bash)"
+NIX_BUILD_SHELL="${NIX_BUILD_SHELL:-$NIX_PROFILE_BINPATH/bash}"
+
+export NIX_REMOTE=daemon
+NIX_PATH="nixpkgs=$(${NIX_BUILD} fetch-nixpkgs.nix -o nixpkgs)"
+export PATH=$NIX_PROFILE_BINPATH:$PATH
+export NIX_PATH
+export NIX_BUILD_SHELL

.buildkite/pipeline.yml

@@ -1,30 +1,30 @@
 steps:
   - label: 'hlint'
-    command: 'scripts/ci/nix-shell.sh -p hlint moreutils --run scripts/haskell/lint.sh'
+    command: 'nix-shell -p hlint moreutils --run scripts/haskell/lint.sh'
     agents:
       system: x86_64-linux
 
   - label: 'stack2nix'
-    command: 'scripts/ci/nix-shell.sh -p cabal2nix stack cabal-install ghc moreutils expect -Q -j 4 --run scripts/check-stack2nix.sh'
+    command: 'nix-shell -Q -j 4 --run scripts/check-stack2nix.sh'
     agents:
       system: x86_64-linux
 
   - label: 'cardano-x86_64-linux'
-    command: 'scripts/ci/nix-shell.sh --run scripts/ci/ci.sh'
+    command: 'nix-shell --run scripts/ci/ci.sh'
     agents:
       system: x86_64-linux
 
   - label: 'cardano-x86_64-darwin'
-    command: 'scripts/ci/nix-shell.sh --run scripts/ci/ci.sh'
+    command: 'nix-shell --run scripts/ci/ci.sh'
     agents:
       system: x86_64-darwin
 
   - label: 'release.nix'
-    command: 'scripts/ci/nix-shell.sh --run scripts/ci/check-hydra.sh'
+    command: 'nix-shell --run scripts/ci/check-hydra.sh'
     agents:
       system: x86_64-linux
 
   - label: 'explorer frontend: checking generated dependencies'
-    command: 'scripts/ci/nix-shell.sh --run "cd explorer/frontend && ./nix/generate-frontend-deps.hs --test"'
+    command: "cd explorer/frontend && ./nix/generate-frontend-deps.hs --test"
     agents:
       system: x86_64-linux

pkgs/generate.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i bash -p bash
+#!nix-shell -i bash -p bash cabal2nix stack cabal-install ghc
 
 # regenerate the `pkgs/default.nix` file based on the current contents of cardano-sl.cabal and stack.yaml
 

scripts/check-stack2nix.sh

@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash -p git bash
 
 # check and warn if `pkgs/default.nix` is out of date