docker-template

#!/bin/bash 
#
# Template engine for LOFAR
#
#   Reads stdin, replaces variables, writes stdout.
#
#   Variables replaced:
#       ${LOFAR_BRANCH_NAME}  = Name of this branch, relative to root
#       ${LOFAR_BRANCH_URL}   = Full subversion URL for this branch
#       ${LOFAR_TAG}          = Tag for a Docker image
#       ${LOFAR_REVISION}     = SVN revision number of this checkout (or HEAD if trunk)
#       ${NOW}          = now in UTC (format: 2016-01-01 10:11:12)
#       ${BUILD_UID}    = uid of building user (=caller)
#

# ----- LOFAR_BRANCH_NAME = branches/LOFAR-Task1234 -----
# ----- LOFAR_BRANCH_NAME = trunk -----
# ----- LOFAR_BRANCH_NAME = tags/LOFAR-Release-2_15_1 -----
# ----- LOFAR_BRANCH_NAME = UNKNOWN -----

function usage() {
  echo "$0 [-v VERSIONDOCKER]"
  echo ""
  echo "  -v VERSIONDOCKER   Provides location of 'versiondocker' executable"
  echo ""
  exit 1
}

# Defaults
VERSION_DOCKER="versiondocker"

# Parse options
while getopts "hv:" opt; do
  case $opt in
    h)  usage
        ;;
    v)  VERSION_DOCKER="$OPTARG"
        ;;
    \?) error "Invalid option: -$OPTARG"
        ;;
    :)  error "Option requires an argument: -$OPTARG"
        ;;
  esac
done

# Make sure we obtain info about the project source!
# Drop stderr to prevent logger output from contaminating our output
VERSION_INFO=`$VERSION_DOCKER 2>/dev/null`

# Extract branch name w.r.t. repository root, e.g. branches/LOFAR-Task1234
export LOFAR_BRANCH_NAME=`echo "$VERSION_INFO" | perl -ne 'print "$1" if /branch += +(.+)/;'`

# ----- LOFAR_BRANCH_URL = https://svn.astron.nl/LOFAR/branches/LOFAR-Task1234 -----
# ----- LOFAR_BRANCH_URL = https://svn.astron.nl/LOFAR/trunk -----
# ----- LOFAR_BRANCH_URL = https://svn.astron.nl/LOFAR/tags/LOFAR-Release-2_15_1 -----

export LOFAR_BRANCH_URL="https://svn.astron.nl/LOFAR/${LOFAR_BRANCH_NAME}"

# ----- LOFAR_TAG = LOFAR-Task1234 -----
# ----- LOFAR_TAG = trunk -----
# ----- LOFAR_TAG = LOFAR-Release-2_15_1 -----

case "${LOFAR_BRANCH_NAME}" in
  trunk)      export LOFAR_TAG=trunk ;;
  branches/*) export LOFAR_TAG=${LOFAR_BRANCH_NAME##branches/} ;;
  tags/*)     export LOFAR_TAG=${LOFAR_BRANCH_NAME##tags/} ;;
  *)          export LOFAR_TAG=latest ;;
esac

# ----- LOFAR_REVISION = 12345 -----

export LOFAR_REVISION=`echo "$VERSION_INFO" | perl -ne 'print "$1" if /overall revision += +([0-9]+)/;'`

# ----- NOW = 2016-01-01 10:11:12 -----

export NOW="`date -u +'%F %T'`"

# ----- BUILD_UID = 1001 ----

export BUILD_UID=`id -u`

# ----- Process input -----

# Insert our knowledge when processing stdin -> stdout
envsubst '$LOFAR_BRANCH_NAME $LOFAR_BRANCH_URL $LOFAR_TAG $LOFAR_REVISION $NOW $BUILD_UID'