Enable ocaml code formatting with dune fmt

.git-blame-ignore-revs

@@ -0,0 +1,2 @@
+# dune fmt ocaml code
+d67590d2cd504ed931e225834746f9e13b3a27fa

.github/workflows/test.yml

@@ -93,3 +93,15 @@ jobs:
           system-features = nixos-test benchmark big-parallel kvm
     - uses: DeterminateSystems/magic-nix-cache-action@v8
     - run: cd controller && nix-shell --run 'bin/test --force --no-buffer'
+
+  ocaml-formatting:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v18
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+        extra_nix_config: |
+          system-features = nixos-test benchmark big-parallel kvm
+    - uses: DeterminateSystems/magic-nix-cache-action@v8
+    - run: cd controller && nix-shell --run 'dune build @fmt'

controller/.ocamlformat

@@ -0,0 +1,13 @@
+version = 0.26.1
+
+profile = ocamlformat
+
+break-infix = wrap-or-vertical
+doc-comments = before
+field-space = loose
+indicate-multiline-delimiters = closing-on-separate-line
+space-around-arrays = true
+space-around-lists = true
+space-around-records = true
+space-around-variants = true
+type-decl = sparse

controller/bin/watch-command

@@ -1,9 +1,16 @@
 #!/usr/bin/env bash
 set -euo pipefail
+
+AUTO_FORMAT=${AUTO_FORMAT:-}
+
 cd $(dirname "$0")/..
 
 clear
 
+if [ ! -z "$AUTO_FORMAT" ]; then
+    dune fmt || true
+fi
+
 if bin/build; then
 
   bin/stop-server || true