feature: support custom hadolint path

Fixes: #13

README.md

@@ -23,6 +23,7 @@ jobs:
 | error_level   | `0`            | Fail CI if hadolint emits output (`-1`: never, `0`: error, `1`: warning, `2`: info)                   |
 | annotate      | true           | Annotate code inline in the github PR viewer (`true`/`false`)                                         |
 | output_format |                | Set output format (choose between `tty`, `json`, `checkstyle`, `codeclimate` or `gitlab_codeclimate`) |
+| hadolint_path |                | Absolute path to hadolint binary. If unset, it is assumed to exist in `$PATH`                         |
 
 ## Hadolint version
 

action.yml

@@ -23,6 +23,10 @@ inputs:
     description: Set output format (choose between `tty`, `json`, `checkstyle`, `codeclimate` or `gitlab_codeclimate`)
     required: false
     default:
+  hadolint_path:
+    description: Absolute path to hadolint binary. If unset, it is assumed to exist in `$PATH`
+    required: false
+    default:
 
 outputs:
   hadolint_output:

lib/hadolint.sh

@@ -2,6 +2,9 @@
 
 function output_hadolint_version() {
   local HADOLINT_VERSION=""
+  # I cannot pass path directly here; both tests and invoking `hadolint`
+  # directly would fail.
+  alias hadolint='${HADOLINT_PATH}'
   HADOLINT_VERSION="$(hadolint --version | cut -d " " -f 4)"
   echo "::set-output name=hadolint_version::${HADOLINT_VERSION}"
 }

lib/main.sh

@@ -5,7 +5,7 @@ CONFIG_FILE=${config_file:-}
 ERRORLEVEL=${error_level:=0}
 ANNOTATE=${annotate:="true"}
 OUTPUT_FORMAT=${output_format:-}
-
+HADOLINT_PATH=${hadolint_path:="hadolint"}
 
 function exit_with_error() {
   echo "${1}"
@@ -14,7 +14,7 @@ function exit_with_error() {
 
 function run() {
   # Check for dependencies
-  for executable in hadolint jq; do
+  for executable in "${HADOLINT_PATH}" jq; do
     if ! command -v ${executable} &> /dev/null; then
       echo "Cannot find required binary ${executable}. Is it in \$PATH?"
       exit 1

test/e2e.sh

@@ -12,7 +12,12 @@ test_default_path_with_dockerfile() {
   assert_status_code 0 "../../${HL}"
 }
 
-test_custom_path() {
+test_custom_hadolint_path() {
+  # Since test runners should have jq installed, lets find path and set it
+  assert_status_code 0 "hadolint_path=$(which hadolint) dockerfile=fixtures/default-path/Dockerfile ${HL}"
+}
+
+test_custom_dockerfile_path() {
   assert_status_code 0 "dockerfile=fixtures/default-path/Dockerfile ${HL}"
 }