compile

#!/bin/bash
#
# Usage:
#  bin/compile BUILD_DIR CACHE_DIR ENV_DIR
# Example
#   BUILD_DIR is /tmp/build_5b72bfcaef1adfe4bb7a9e34d80201fc
#   CACHE_DIR is  app
#  The contents of CACHE_DIR will be persisted between builds.

set -eou pipefail
IFS=$'\n\t'
unset CDPATH

# Always log finish, bash pseudo-signal: EXIT
# Usage:
#   trap finish EXIT
finish() {
  echo "       END Running script: ${0##*/}"
}

# Log errors, if any, bash pseudo-signal: ERR
# Usage:
#   trap 'finish_error $LINENO' ERR
finish_error()  {
  errcode=$?
  echo "       END ERROR Running script: ${0##*/}:$1: exited with '${errcode}'."
}

trap 'finish' EXIT
trap 'finish_error $LINENO' ERR

# Influenced by https://dev.to/thiht/shell-scripts-matter
# And see https://github.com/bf4/Notes/wiki/Shell-Scripting

logstamp() { printf "[%s]" "$(TZ='America/Chicago' date +'%Y-%m-%d %H:%M:%S')" ; }
topic()    { echo "-----> $(logstamp) $*" ; }
info()    { echo "       $*" ; }
indent()  { sed -u 's/^/       /' ; } # it always runs on linux. on darwin is 'sed -l'

BUILD_DIR="$1"
CACHE_DIR="$2"
mkdir -p "$BUILD_DIR" "$CACHE_DIR"
# shellcheck disable=SC2034
ENV_DIR="${3}"
# echo "$STACK"
# echo "$SOURCE_VERSION"
# See https://devcenter.heroku.com/articles/buildpack-api#bin-compile-summary

BIN_DIR="$(cd "$(dirname "$0")"; pwd)" # absolute path
LP_DIR="$(cd "$(dirname "$0")"; cd ..; pwd)"
ROOT_DIR="$(dirname "$BIN_DIR")"

info "BIN_DIR=${BIN_DIR}, ROOT_DIR=${ROOT_DIR}, BUILD_DIR=${BUILD_DIR}, CACHE_DIR=${CACHE_DIR}, pwd=$(pwd)"

load_env_vars() {
  local env_var; env_var="${1:-}"
  until [ -z "$env_var" ]; do [ -f "$ENV_DIR/$env_var" ] && export "$env_var=$(cat "$ENV_DIR/$env_var")"; shift ; env_var="${1:-}" ; done
}
load_env_vars "FREETDS_VERSION" "FREETDS_ARCHIVE_NAME" "TDS_VERSION" "FREETDS_REBUILD"

FREETDS_VERSION="${FREETDS_VERSION:-1.00.109}"
FREETDS_ARCHIVE_NAME="${FREETDS_ARCHIVE_NAME:-freetds-${FREETDS_VERSION}}"
TDS_VERSION="${TDS_VERSION:-7.3}" # or TDSVER

CACHED_TAR="${CACHE_DIR}/freetds-${FREETDS_VERSION}-heroku.tar.bz2"
# Default rebuild to true since I'm having issues linking the library to tiny_tds gem with a cached build.
if [ "${FREETDS_REBUILD:-}" = "true" ]; then
  rm -f "$CACHED_TAR"
fi
# This installation target is in the BUILD_DIR, which means that
# it'll end up in the slug at runtime.
BUILD_TARGET_DIR="${BUILD_DIR}/freetds"
mkdir -p "${BUILD_TARGET_DIR}"

# This is the path that will be used at dyno runtime, and in which we build.
APP_TARGET_DIR="/app/freetds"
mkdir -p "${APP_TARGET_DIR}"

configure_app_env_vars() {
  topic "Creating .profile.d entry"
  mkdir -p "${BUILD_DIR}/.profile.d"

  # These exports must point to /app, because the profile is
  # executed in a running dyno, not the buildpack environment
  cat <<EOF > "${BUILD_DIR}/.profile.d/freetds.sh"
  export PATH="${APP_TARGET_DIR}/bin:$PATH"
  # tiny_tds extconf.rb uses FREETDS_DIR
  # https://github.com/rails-sqlserver/tiny_tds/blob/5046755ca91594003f8b3ca541d136f3ed859973/ext/tiny_tds/extconf.rb#L36-L38
  export FREETDS_DIR="${APP_TARGET_DIR}"
  export LD_LIBRARY_PATH="${APP_TARGET_DIR}/lib:${LD_LIBRARY_PATH:-/usr/local/lib}"
  export LD_RUN_PATH="${APP_TARGET_DIR}/lib:${LD_RUN_PATH:-/usr/local/lib}"
  export LIBRARY_PATH="${APP_TARGET_DIR}/lib:${LIBRARY_PATH:-/usr/local/lib}"
  export SYBASE="${APP_TARGET_DIR}"
EOF
 chmod +x "${BUILD_DIR}/.profile.d/freetds.sh"
 echo "configured APP env vars:" | indent
 indent < "${BUILD_DIR}/.profile.d/freetds.sh"
 # shellcheck disable=SC1090
 . "${BUILD_DIR}/.profile.d/freetds.sh"
}

configure_buildpack_env_vars() {
  # These exports point to the build directory, not to /app, so that
  # they work for later buildpacks.
  export PATH="${BUILD_TARGET_DIR}/bin:$PATH"
  export FREETDS_DIR="${BUILD_TARGET_DIR}"
  export LD_LIBRARY_PATH="${BUILD_TARGET_DIR}/lib:${LD_LIBRARY_PATH:-/usr/local/lib}"
  export LD_RUN_PATH="${BUILD_TARGET_DIR}/lib:${LD_RUN_PATH:-/usr/local/lib}"
  export LIBRARY_PATH="${BUILD_TARGET_DIR}/lib:${LIBRARY_PATH:-/usr/local/lib}"
  export SYBASE="${APP_TARGET_DIR}"
  # give environment to later buildpacks
  export | grep -E -e ' (PATH|LD_LIBRARY_PATH|LIBRARY_PATH|FREETDS_DIR|SYBASE)=' > "${LP_DIR}/export"

  echo "configured BUILDPACK env vars:" | indent
  indent < "${LP_DIR}/export"
}

download_and_extract_freetds_archive() {
  FREETDS_FILE="$FREETDS_ARCHIVE_NAME.tar.gz"
  FREETDS_URL="https://www.freetds.org/files/stable/${FREETDS_FILE}"
  # TODO(BF): Print log when HEROKUR_FREETDS_BUILDPACK_DEBUG is set
  # TODO(BF): Consider calculating and verifying SHA256: openssl dgst -sha256 < "$FREETDS_FILE"
  curl -s "$FREETDS_URL" | tar xzvf - -C "${BUILD_DIR}" > "${BUILD_DIR}/build_log-unpack.log" # Can't write to the archive dir until it exists
  mv "${BUILD_DIR}/build_log-unpack.log" "${BUILD_DIR}/${FREETDS_ARCHIVE_NAME}/"
}

build_and_install_freetds() {
  topic "Building FreeTDS against OpenSSL $(openssl version)"
  ( # directory changes in subshells have no effect
    cd "${BUILD_DIR}/${FREETDS_ARCHIVE_NAME}"

    # We must build at /app/... rather than in the BUILD_DIR because
    # the installation hardwires some paths and symlinks. In order for
    # these to be in the right location at dyno runtime, we have to
    # build using the same path that applies at dyno runtime.

    # FreeTDS advises caching the build options as below
    # adding --disable-odbc making linking easier and we don't need it
    # adding --disable-debug to speed up compile
    cat <<EOF > ".build_options"
    ./configure \
      "--prefix=${APP_TARGET_DIR}" \
      --disable-odbc \
      --disable-debug \
      "--with-tdsver=${TDS_VERSION}"
EOF
    # TODO(BF): Print log when HEROKUR_FREETDS_BUILDPACK_DEBUG is set
    /bin/bash .build_options > build_log-configure.stdout.log 2> build_log-configure.stderr.log
    # Flush make output to log since a file will be faster than printing to the screen.
    # TODO(BF): Print log when HEROKUR_FREETDS_BUILDPACK_DEBUG is set
    {
      make && make install && make clean
    } > build_log-make_install.stdout.log 2> build_log-make_install.stderr.log
    cp .build_options build_log-* "${APP_TARGET_DIR}/"

    cd "$BUILD_DIR"
    # shellcheck disable=SC2115
    rm -rf "${BUILD_DIR}/${FREETDS_ARCHIVE_NAME}"
  )
}

cache_build_artifacts_for_future_deploys() {
  topic "Caching FreeTDS installation"
  ( # directory changes in subshells have no effect
    cd "${APP_TARGET_DIR}"
    # TODO(BF): Consider removing the documentation before tarring
    # rm -rf share
    tar cjf "${CACHED_TAR}" . | indent
  )
}

main() {
  topic "FreeTDS ${FREETDS_VERSION} building in ${BUILD_DIR}"

  configure_app_env_vars

  if [ ! -f "$CACHED_TAR" ]; then
    info "Cached files not found - downloading and unpacking..."
    download_and_extract_freetds_archive

    build_and_install_freetds

    topic "Testing build"
    "$APP_TARGET_DIR/bin/tsql" -C | indent

    cache_build_artifacts_for_future_deploys
  fi

  info "Unpacking cached files..."
  tar xjf "${CACHED_TAR}" -C "${BUILD_TARGET_DIR}" | indent

  configure_buildpack_env_vars

  info "Install of FreeTDS ${FREETDS_VERSION} complete"
}

main