fix(dockerfile): build custom Docker image with the latest Alpine; fi…

…x link to linter in README

.github/workflows/build_and_push_docker_image.yml

@@ -20,9 +20,9 @@ env:
 jobs:
     build-and-push:
         runs-on: "ubuntu-latest"
-        # NOTE: building and pushing Docker image of Dockerfile linter take around 1 minute.
-        # If this job takes more than 5 minutes, it means that something is wrong.
-        timeout-minutes: 5
+        # NOTE: building and pushing Docker image of Dockerfile linter take around 5 minutes.
+        # If this job takes more than 15 minutes, it means that something is wrong.
+        timeout-minutes: 15
         steps:
             - name: "Checkout ${{ github.event.repository.name }}"
               uses: "actions/checkout@v4"

.github/workflows/validate_new_changes.yml

@@ -14,9 +14,9 @@ env:
 jobs:
     validate-dockerfile-linter-image:
         runs-on: "ubuntu-latest"
-        # NOTE: building and running Docker image of Dockerfile linter take around 1 minute.
-        # If this job takes more than 5 minutes, it means that something is wrong.
-        timeout-minutes: 5
+        # NOTE: building and running Docker image of Dockerfile linter take around 5 minutes.
+        # If this job takes more than 15 minutes, it means that something is wrong.
+        timeout-minutes: 15
         steps:
             - name: "Checkout ${{ github.event.repository.name }}"
               uses: "actions/checkout@v4"

Dockerfile

@@ -1,12 +1,21 @@
-FROM ghcr.io/hadolint/hadolint:2.12.1-beta-alpine
+FROM alpine:3.20
 
-COPY ./ /linter_workdir
+RUN mkdir /linter_workdir
+
+RUN addgroup -S lintergroup && adduser -S linteruser -G lintergroup && chown -R linteruser:lintergroup /linter_workdir
+
+RUN apk add --no-cache wget=1.24.5-r0 \
+    && wget --progress=dot:mega -O /linter_workdir/hadolint https://github.com/hadolint/hadolint/releases/download/v2.12.0/hadolint-Linux-x86_64 \
+    && chmod +x /linter_workdir/hadolint \
+    && apk del wget
 
 # NOTE: we need to have a separate directory for linter to work only with needed files,
 # not with files from the entire system.
 WORKDIR /linter_workdir
 
-HEALTHCHECK --timeout=1s --retries=1 CMD hadolint --version || exit 1
+USER linteruser
+
+HEALTHCHECK --timeout=1s --retries=1 CMD /linter_workdir/hadolint --version || exit 1
 
 ENTRYPOINT ["/bin/sh", "-c", "find /linter_workdir/repo -name 'Dockerfile*' -type f | \
-while read -r dockerfile; do hadolint \"$dockerfile\"; done"]
+while read -r dockerfile; do /linter_workdir/hadolint \"$dockerfile\"; done"]

README.md

@@ -2,7 +2,7 @@
 
 [![image size](https://ghcr-badge.egpl.dev/articola-tools/dockerfile-linter/size?color=dodgerblue)](https://ghcr-badge.egpl.dev/articola-tools/dockerfile-linter/size?color=dodgerblue)
 
-This repo contains Dockerfile with preconfigured [Dockerfile linter](https://github.com/hadolint/hadolint?tab=readme-ov-file#rules).
+This repo contains Dockerfile with preconfigured [Dockerfile linter](https://github.com/hadolint/hadolint).
 This linter is used in Articola Tools organization's repositories to lint Dockerfile files like
 other linters.