chore: setup dockerfile and travis

Author: wei

.travis.yml

@@ -0,0 +1,29 @@
+language: minimal
+sudo: required
+
+services:
+  - docker
+
+env:
+  - IMAGE_NAME=instantbox/cron
+  
+script:
+  - docker pull "$IMAGE_NAME" || true
+  - docker build --cache-from "$IMAGE_NAME" 
+      --build-arg BUILD_DATE="$(date -u +'%Y-%m-%dT%H:%M:%SZ')" 
+      --build-arg VCS_REF="$TRAVIS_COMMIT" 
+      -t "build/$IMAGE_NAME" -f ./Dockerfile .
+  - docker run -d -P --name temp "build/$IMAGE_NAME"
+  - docker rm -f temp || true
+  
+after_success:
+  - if [[ "$TRAVIS_BRANCH" == "latest" && "$TRAVIS_PULL_REQUEST" == "false" ]]; then 
+      docker login -u "$DOCKER_USERNAME" -p "$DOCKER_PASSWORD_SECURE";
+      docker tag "build/$IMAGE_NAME" "$IMAGE_NAME";
+      docker push "$IMAGE_NAME";
+    fi
+  - if [[ -n "$TRAVIS_TAG" ]]; then
+      docker login -u "$DOCKER_USERNAME" -p "$DOCKER_PASSWORD_SECURE";
+      docker tag "build/$IMAGENAME" "$IMAGENAME:$TRAVIS_TAG";
+      docker push "$IMAGE_NAME:$TRAVIS_TAG";
+    fi

Dockerfile

@@ -1,9 +1,23 @@
 FROM alpine:latest
-MAINTAINER [email protected]
+
+LABEL \
+  org.label-schema.schema-version="1.0" \
+  org.label-schema.name="cron" \
+  org.label-schema.vcs-url="https://github.com/instantbox/cron" \
+  maintainer="Instantbox Team <[email protected]>"
 
-RUN apk update && apk add dcron curl wget rsync ca-certificates && rm -rf /var/cache/apk/*
+RUN apk add --no-cache \
+  dcron \
+  curl \
+  wget \
+  rsync \
+  ca-certificates \
+  ;
 
-RUN mkdir -p /var/log/cron && mkdir -m 0644 -p /var/spool/cron/crontabs && touch /var/log/cron/cron.log && mkdir -m 0644 -p /etc/cron.d
+RUN mkdir -p /var/log/cron \
+  && mkdir -m 0644 -p /var/spool/cron/crontabs \
+  && touch /var/log/cron/cron.log \
+  && mkdir -m 0644 -p /etc/cron.d
 
 COPY /scripts/* /