Dockerfile linter

Author: ralsina

.hadolint.yml

@@ -0,0 +1,3 @@
+ignored:
+  - DL3018
+  - DL3059

Dockerfile

@@ -1,5 +1,13 @@
-FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine as build
-RUN apk update && apk add crystal shards yaml-dev openssl-dev zlib-dev libxml2-dev make && apk cache clean
+FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine:3.20 AS build
+RUN apk add --no-cache \
+    crystal \
+    shards \
+    yaml-dev \
+    openssl-dev \
+    zlib-dev \
+    libxml2-dev \
+    make
+RUN rm -rf /var/cache/apk/*
 RUN addgroup -S app && adduser app -S -G app
 WORKDIR /home/app
 COPY shard.yml Makefile ./
@@ -9,8 +17,22 @@ COPY runtimes/ runtimes/
 RUN make
 # RUN strip bin/*
 
-FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine as ship
-RUN apk update && apk add caddy nss-tools multirun docker openssl zlib yaml pcre2 gc libevent libgcc libxml2 ttyd && apk cache clean
+FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine:3.20 AS ship
+RUN apk add --no-cache \
+    caddy \
+    nss-tools \
+    multirun \
+    docker \
+    openssl \
+    zlib \
+    yaml \
+    pcre2 \
+    gc \
+    libevent \
+    libgcc \
+    libxml2 \
+    ttyd
+RUN rm -rf /var/cache/apk/*
 
 # Unprivileged user
 RUN addgroup -S app && adduser app -S -G app
@@ -21,7 +43,6 @@ COPY public/ public/
 COPY --from=build /home/app/bin/faaso-daemon /home/app/bin/faaso /usr/bin/
 
 # Mount points for persistent data
-RUN mkdir /secrets
-RUN mkdir /config
+RUN mkdir /secrets /config
 
 CMD ["/usr/bin/multirun", "-v", "faaso-daemon", "caddy run --config config/Caddyfile"]