Add recursive linting

action.yml

@@ -6,6 +6,10 @@ inputs:
     required: false
     description: 'The path to the Dockerfile to lint'
     default: 'Dockerfile'
+  recursive:
+    required: false
+    description: 'Search for lint dockerfiles recuresivly'
+    default: 'false'
   format:
     required: false
     description: |
@@ -39,6 +43,7 @@ runs:
   env:
     HADOLINT_CONFIG: ${{ inputs.config }}
     HADOLINT_IGNORE: ${{ inputs.ignore }}
+    HADOLINT_RECURSIVE: ${{ inputs.recursive }}
 branding:
   icon: 'layers'
   color: 'purple'

hadolint.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 # The problem-matcher definition must be present in the repository
 # checkout (outside the Docker container running hadolint). We create
@@ -27,5 +27,14 @@ for i in $HADOLINT_IGNORE; do
   HADOLINT_IGNORE_CMDLINE="${HADOLINT_IGNORE_CMDLINE} --ignore=${i}"
 done
 
-# shellcheck disable=SC2086
-hadolint $HADOLINT_IGNORE_CMDLINE $HADOLINT_CONFIG "$@"
+if [ "$HADOLINT_RECURSIVE" = "true" ]; then
+  shopt -s globstar
+
+  filename="${!#}"
+  flags="${@:1:$#-1}"
+
+  hadolint $HADOLINT_IGNORE_CMDLINE $HADOLINT_CONFIG $flags **/$filename
+else
+  # shellcheck disable=SC2086
+  hadolint $HADOLINT_IGNORE_CMDLINE $HADOLINT_CONFIG "$@"
+fi