Generic build.sh script for Dockerfiles that loads and saves versioning in version.txt file in same folder as docker file.

build.sh

#!/usr/bin/env bash

# Works for any Dockerfile, hardcoded service name and docker org these could be pulled from config or environment variables

SERVICE_NAME=SET_SERVICE_NAME
DOCKER_ORG=SET_DOCKER_ORG

PUBLISH=false

VERSION=false
MAJOR=false
MINOR=false
PATCH=false
UPREV=false

Showhelp () {
  scriptname=`basename "$0"`
  echo "
${scriptname} <options>

  Options:
    -M, --major - Increment the major version number
    -m, --minor - Increment the minor version number
    -p, --patch - Increment the patch version number
    -v <version>, --version <version> - Set the version number
    -P, --publish - Publish the image to docker hub

    -h or --help - Show this screen
    "
    exit 0
}

GetVersion () {
  if [ -f "version.txt" ]; then
    head -n 1 "version.txt"
  else
    echo "0.0.1"
  fi
}

export SKIP_PREFLIGHT_CHECK=true

while [[ $# > 0 ]]
do
  key="$1"
  case $key in
    -M|--major)
      MAJOR=true
      UPREV=true
    ;;
    -m|--minor)
      MINOR=true
      UPREV=true
    ;;
    -p|--patch)
      PATCH=true
      UPREV=true
    ;;
    -v|--version)
      VERSION="$2"
      shift
    ;;
    -P|--publish)
      PUBLISH=true
    ;;
    -h|--help)
      Showhelp
    ;;
    *)
    # unknown option
    ;;  esac
  shift # past argument or value
done

# Get the current script directory

SOURCE="${BASH_SOURCE[0]}"
while [ -h "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  DIR="$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )"
  SOURCE="$(readlink "$SOURCE")"
  [[ $SOURCE != /* ]] && SOURCE="$DIR/$SOURCE" # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
done
DIR="$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )"

cd $DIR

if [[ $UPREV != true ]]; then
  PATCH=true
fi

if [[ $UPREV == true ]]; then
  if [[ $VERSION == false ]]; then
    VERSION=$(GetVersion)
  fi
  a=( ${VERSION//./ } )
  if [[ $MAJOR == true ]]; then
    ((a[0]++))
    a[1]=0
    a[2]=0
  fi

  if [[ $MINOR == true ]]; then
    ((a[1]++))
    a[2]=0
  fi

  if [[ $PATCH == true ]]; then
    ((a[2]++))
  fi

  VERSION="${a[0]}.${a[1]}.${a[2]}"
  echo "*****Calculated next build number: $VERSION*****"
fi

if [[ $VERSION == false ]]; then
  VERSION=$(GetVersion)
else
  echo "$VERSION">version.txt
fi
SERVICE_VERSION="v${VERSION}"

EXITED=`docker ps -aq --filter status=exited`
if [[ "$EXITED" != "" ]]; then
  docker rm $(docker ps -aq --filter status=exited)
fi
docker image rm $SERVICE_NAME:latest
docker image rm $DOCKER_ORG/$SERVICE_NAME:latest
docker image rm $DOCKER_ORG/$SERVICE_NAME:${SERVICE_VERSION}

set -ex

docker build --rm --tag $SERVICE_NAME:latest .
docker tag $SERVICE_NAME:latest $DOCKER_ORG/$SERVICE_NAME:latest
docker tag $SERVICE_NAME:latest $DOCKER_ORG/$SERVICE_NAME:${SERVICE_VERSION}

if [[ $PUBLISH == true ]]; then
  docker push $DOCKER_ORG/$SERVICE_NAME:latest
  docker push $DOCKER_ORG/$SERVICE_NAME:${SERVICE_VERSION}
fi