upgrade-mistral-wf-0.8

#!/usr/bin/env bash
#
## Mistral YAQL Migration tool
#
# This tool inspects a given Mistral workflow, parses it using a few
# regex filters, and attempts to rewrite the file to adhere to the
# updated YAQL syntax introduced in https://review.openstack.org/#/c/157741/
#
# There appear to be two different ways that the old style YAQL is
# represented in workflows. This includes:
#   * bare         - (node: $.node)
#   * interpolated - (node: 'Node: {$.node}')
#   * functions    - (node: range(0, $.nodes).list() )
#
# This command runs sed with two passes attempting to clean up a given
# workflow. This command will also ensure a backup exists in the event
# that things do not go as expected to prevent data loss.
#######################################################################

function usage {
  echo "Usage: `basename $0` <mistral file>"
}

# Exit Codes
OK=0
E_BADARGS=2
E_NOTAFILE=3
E_UNKNOWNOS=4
E_SEDMISSING=5

# Let's figure out what OS we're on to pass the right flags
# to sed. Silly GNU vs BSD!
if [[ "$OSTYPE" == "linux-gnu" ]]; then
  SED_ARGS=""
elif [[ "$OSTYPE" == "darwin"* ]]; then
  SED_ARGS="-E"
else
  echo "Not sure how best to handle sed on your system... unknown OS"
  exit $E_UNKNOWNOS
fi

SED=`which sed`
if [[ $? -ne 0 ]]; then
  echo "sed not found on this system... exiting"
  exit $E_SEDMISSING
fi

# Check for a proper number of command line args:
EXPECTED_ARGS=1
if [[ $# -ne $EXPECTED_ARGS ]]; then
  usage
  exit $E_BADARGS
else
  WORKFLOW=$1
fi

# Make sure any arguments are actually files that exist
if [[ ! -f $WORKFLOW ]]; then
  echo "Argument supplied is not a file..."
  usage
  exit $E_NOTAFILE
fi

# Great, got this far. Let's actually start to slice and dice.
## First, make a backup
cp $WORKFLOW ${WORKFLOW}.bak

## Pass through in phases, because a few too many variables to make a master regex.
cat $WORKFLOW | \
  sed $SED_ARGS 's/{([][_$.0-9a-z+\s]+)}/<% \1 %>/g'  | \
  sed $SED_ARGS 's/([][_$.0-9a-z]+\(.*\))/<% \1 %>/g' | \
  sed $SED_ARGS 's/(\$\.[][a-z0-9_.]+)/<% \1 %>/g'    | \
  sed $SED_ARGS 's/<% (<% [][a-z0-9._$]+ %>) %>/\1/g' | \
  sed $SED_ARGS 's/<% ([][$.a-z0-9_]+) %>\)/\1)/g' > ${WORKFLOW}.new

## And put our file back where it belongs...
mv ${WORKFLOW}.new $WORKFLOW