from Docker-Images repo

.travis.yml

+language: bash
+dist: bionic
+services: 
+  - docker
+branches:
+  only:
+  - master
+env:
+  global:
+  - DOCKER_USERNAME=yousiki
+  - DOCKER_IMAGE=smartdns
+script:
+  - echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin        
+  - export IMAGE_NAME=$DOCKER_USERNAME/$DOCKER_IMAGE:latest
+  - docker build -t $IMAGE_NAME .
+  - travis_wait 30 docker push $IMAGE_NAME
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Dockerfile

+FROM ubuntu:latest AS downloader
+
+RUN apt update && \
+    apt install -y curl wget
+
+ADD downloader.sh downloader.sh
+
+RUN sh downloader.sh
+
+FROM ubuntu:latest
+
+COPY --from=downloader /smartdns.deb /
+
+RUN dpkg -i *.deb && rm *.deb && mkdir -p /var/log/smartdns
+
+EXPOSE 53/tcp
+EXPOSE 53/udp
+
+VOLUME [ "/etc/smartdns" ]
+
+ENTRYPOINT [ "smartdns" ]
+
+CMD ["-f -c /etc/smartdns/smartdns.conf"]
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downloader.sh

+curl -s https://api.github.com/repos/pymumu/smartdns/releases/latest \
+  | grep browser_download_url \
+  | grep $(arch) \
+  | grep deb \
+  | cut -d '"' -f 4 \
+  | wget -i - -O smartdns.deb
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