The Dockerfile.dn File in the Hello World Docker Demonstration

This topic lists and describes the Dockerfile.dn file from the Hello World Docker demonstration. The Dockerfile is listed in its entirety and a following table describes the various Dockerfile commands. The line numbers in the listings of the Dockerfile have been added to aid readability. They are not present in the supplied Dockerfile.

001  # Copyright (C) Micro Focus 2018. All rights reserved. 
002  # This sample code is supplied for demonstration purposes only
003  # on an "as is" basis and is for use at your own risk. 
004  
005  ARG MFPRODBASE=
006  ARG DTAG=win_4.0
007  FROM microfocus/vcbuildtools-build:${DTAG} as build-env
008  
009  LABEL com.microfocus.is-example="true"
010  
011  ARG Platform=AnyCPU
012  ARG Config=Release
013  
014  # Copy the src folder to c:\src in the container
015  COPY src "c:\\src"
016  WORKDIR "c:\\src"
017  
018  # build source using the msbuild project with a output directory of c\app
019  ENV BLDPlatform ${Platform}
020  ENV BLDConfig ${Config}
021  RUN msbuild /p:OutDir=c:\app /p:Configuration=%BLDConfig%;Platform=%BLDPlatform% DNHelloWorld.cblproj
022  
023  # Build runtime image for development or production
024  FROM ${MFPRODBASE}
025  WORKDIR "c:\\app"
026  COPY --from=build-env "c:\\app" "c:\\app"
027  ENTRYPOINT ["DNHelloWorld.exe"]

The commands on the lines in this Dockerfile are as follows:

Lines Description
005 Defines the MFPRODBASE build argument passed by the docker build command.

This argument specifies the Visual COBOL base image for use later in this Dockerfile.

006 - 007 Specifies that the base image to use is the "build" version of the Visual COBOL base image, and gives the name "build-env" for this build stage.
009 Specify the metadata labels for the image that will be created. These labels can be queried using the docker inspect command.
011 - 012 Define build arguments passed by the docker build command:
  • Platform. Specifies the Platform property to use when building.
  • Config. Specifies the Configuration property to use when building.
015 - 016 Copy the Hello World source files to a folder in the image's filesystem and set this folder to be the Docker working directory.
019 - 021 Build the Hello World application, putting the build output in c:\app.
024 Specifies the start of a new build stage that uses the Visual COBOL base image (as specified by the MFPRODBASE) build argument).
025 - 026 Sets the Docker working directory to be c:\app then copies the files from the "build-env" build stage into it.
027 Specifies that running the image runs the Hello World application.