fix: Change terraform_validate hook functionality for subdirectories with terraform files (#100)

* Update terraform_validate.sh:
-Change to the directory before running terraform validate to use the Terraform
 configuration for the appropriate working directory.

* Neglected to change the terraform validate call to use the default of the
current directory.

* Several changes to improve functionality:
- Switch to checking the path for '*.tf' instead of always checking the current
  directory.
- Try to find a '.terraform' directory (which indicates a `terraform init`) and
  change to that directory before running `terraform validate`.

* Fix the description for the terraform_validate hook to reflect changes that were
made in:
35e0356188

* - Clean up comments.
- Adjust variable names to better reflect what they are holding.

.pre-commit-hooks.yaml

@@ -35,7 +35,7 @@
   exclude: \.terraform\/.*$
 
 - id: terraform_validate
-  name: Terraform validate without variables
+  name: Terraform validate
   description: Validates all Terraform configuration files.
   entry: terraform_validate.sh
   language: script

terraform_validate.sh

@@ -15,13 +15,33 @@ done
 for path_uniq in $(echo "${paths[*]}" | tr ' ' '\n' | sort -u); do
   path_uniq="${path_uniq//__REPLACED__SPACE__/ }"
 
-  if [[ -n "$(find . -maxdepth 1 -name '*.tf' -print -quit)" ]]; then
-    if ! terraform validate $path_uniq; then
+  if [[ -n "$(find $path_uniq -maxdepth 1 -name '*.tf' -print -quit)" ]]; then
+
+    starting_path=$(realpath "$path_uniq")
+    terraform_path="$path_uniq"
+
+    # Find the relevant .terraform directory (indicating a 'terraform init'),
+    # but fall through to the current directory.
+    while [[ "$terraform_path" != "." ]]; do
+      if [[ -d "$terraform_path/.terraform" ]]; then
+        break
+      else
+        terraform_path=$(dirname "$terraform_path")
+      fi
+    done
+
+    validate_path="${path_uniq#"$terraform_path"}"
+
+    # Change to the directory that has been initialized, run validation, then
+    # change back to the starting directory.
+    cd "$(realpath "$terraform_path")"
+    if ! terraform validate $validate_path; then
       error=1
       echo
       echo "Failed path: $path_uniq"
       echo "================================"
     fi
+    cd "$starting_path"
   fi
 done