Continuous Delivery with Docker and Jenkins

Adding Dockerfile

Let's create Dockerfile in the root directory of the calculator project:

FROM frolvlad/alpine-oraclejdk8:slimCOPY build/libs/calculator-0.0.1-SNAPSHOT.jar app.jarENTRYPOINT ["java", "-jar", "app.jar"]

The default build directory for Gradle is build/libs/, and calculator-0.0.1-SNAPSHOT.jar is the complete application packaged into one JAR file. Note that Gradle automatically versioned the application using the Maven-style version 0.0.1-SNAPSHOT.

Dockerfile uses a base image that contains JDK 8 (frolvlad/alpine-oraclejdk8:slim). It also copies the application JAR (created by Gradle) and runs it. Let's check if the application builds and runs:

$ ./gradlew build$ docker build -t calculator .$ docker run -p 8080:8080 --name calculator ...