FMT-75 Add hook for packer fmt

.pre-commit-hooks.yaml

@@ -18,6 +18,14 @@
   exclude: \.+.terraform\/.*$
   require_serial: true
 
+- id: packer-fmt
+  name: Packer fmt
+  description: Rewrites all Packer configuration files to a canonical format
+  entry: hooks/packer-fmt.sh
+  language: script
+  files: (\.pkr\.(hcl|json)|\.pkrvars\.hcl)$
+  require_serial: true
+
 - id: packer-validate
   name: Packer validate
   description: Validates all Packer configuration files

README.md

@@ -7,6 +7,7 @@ supported hooks are:
 
 * **terraform-fmt**: Automatically run `terraform fmt` on all Terraform code (`*.tf` files).
 * **terraform-validate**: Automatically run `terraform validate` on all Terraform code (`*.tf` files).
+* **packer-fmt**: Automatically run `packer fmt` on all Packer code (`*.pkr.*` files).
 * **packer-validate**: Automatically run `packer validate` on all Packer code (`*.pkr.*` files).
 * **terragrunt-hclfmt**: Automatically run `terragrunt hclfmt` on all Terragrunt configurations.
 * **tflint**: Automatically run [`tflint`](https://github.com/terraform-linters/tflint) on all Terraform code (`*.tf` files).

hooks/packer-fmt.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+set -e
+
+# OSX GUI apps do not pick up environment variables the same way as Terminal apps and there are no easy solutions,
+# especially as Apple changes the GUI app behavior every release (see https://stackoverflow.com/q/135688/483528). As a
+# workaround to allow GitHub Desktop to work, add this (hopefully harmless) setting here.
+original_path=$PATH
+export PATH=$PATH:/usr/local/bin
+
+# Store and return last failure from fmt so this can validate every directory passed before exiting
+FMT_ERROR=0
+
+for file in "$@"; do
+  packer fmt -diff -check "$file" || FMT_ERROR=$?
+done
+
+# reset path to the original value
+export PATH=$original_path
+
+exit ${FMT_ERROR}