functions

# functions - Common functions used by DevStack components


# apt-get wrapper to set arguments correctly
# apt_get package [package ...]
function apt_get() {
    [[ "$OFFLINE" = "True" ]] && return
    local sudo="sudo"
    [[ "$(id -u)" = "0" ]] && sudo="env"
    $sudo DEBIAN_FRONTEND=noninteractive \
        http_proxy=$http_proxy https_proxy=$https_proxy \
        apt-get --option "Dpkg::Options::=--force-confold" --assume-yes "$@"
}


# Gracefully cp only if source file/dir exists
# cp_it source destination
function cp_it {
    if [ -e $1 ] || [ -d $1 ]; then
        cp -pRL $1 $2
    fi
}


# Checks the exit code of the last command and prints "message"
# if it is non-zero and exits
# die_if_error "message"
function die_if_error() {
    local exitcode=$?
    if [ $exitcode != 0 ]; then
        echo $@
        exit $exitcode
    fi
}


# Checks an environment variable is not set or has length 0 OR if the
# exit code is non-zero and prints "message" and exits
# NOTE: env-var is the variable name without a '$'
# die_if_not_set env-var "message"
function die_if_not_set() {
    local exitcode=$?
    local evar=$1; shift
    if ! is_set $evar || [ $exitcode != 0 ]; then
        echo $@
        exit 99
    fi
}


# Grab a numbered field from python prettytable output
# Fields are numbered starting with 1
# Reverse syntax is supported: -1 is the last field, -2 is second to last, etc.
# get_field field-number
function get_field() {
    while read data; do
        if [ "$1" -lt 0 ]; then
            field="(\$(NF$1))"
        else
            field="\$$(($1 + 1))"
        fi
        echo "$data" | awk -F'[ \t]*\\|[ \t]*' "{print $field}"
    done
}


# git clone only if directory doesn't exist already.  Since ``DEST`` might not
# be owned by the installation user, we create the directory and change the
# ownership to the proper user.
# Set global RECLONE=yes to simulate a clone when dest-dir exists
# git_clone remote dest-dir branch
function git_clone {
    [[ "$OFFLINE" = "True" ]] && return

    GIT_REMOTE=$1
    GIT_DEST=$2
    GIT_BRANCH=$3

    if echo $GIT_BRANCH | egrep -q "^refs"; then
        # If our branch name is a gerrit style refs/changes/...
        if [[ ! -d $GIT_DEST ]]; then
            git clone $GIT_REMOTE $GIT_DEST
        fi
        cd $GIT_DEST
        git fetch $GIT_REMOTE $GIT_BRANCH && git checkout FETCH_HEAD
    else
        # do a full clone only if the directory doesn't exist
        if [[ ! -d $GIT_DEST ]]; then
            git clone $GIT_REMOTE $GIT_DEST
            cd $GIT_DEST
            # This checkout syntax works for both branches and tags
            git checkout $GIT_BRANCH
        elif [[ "$RECLONE" == "yes" ]]; then
            # if it does exist then simulate what clone does if asked to RECLONE
            cd $GIT_DEST
            # set the url to pull from and fetch
            git remote set-url origin $GIT_REMOTE
            git fetch origin
            # remove the existing ignored files (like pyc) as they cause breakage
            # (due to the py files having older timestamps than our pyc, so python
            # thinks the pyc files are correct using them)
            find $GIT_DEST -name '*.pyc' -delete
            git checkout -f origin/$GIT_BRANCH
            # a local branch might not exist
            git branch -D $GIT_BRANCH || true
            git checkout -b $GIT_BRANCH
        fi
    fi
}



# Test if the named environment variable is set and not zero length
# is_set env-var
function is_set() {
    local var=\$"$1"
    if eval "[ -z $var ]"; then
        return 1
    fi
    return 0
}


# pip install wrapper to set cache and proxy environment variables
# pip_install package [package ...]
function pip_install {
    [[ "$OFFLINE" = "True" ]] && return
    sudo PIP_DOWNLOAD_CACHE=/var/cache/pip \
        HTTP_PROXY=$http_proxy \
        HTTPS_PROXY=$https_proxy \
        pip install --use-mirrors $@
}


# Normalize config values to True or False
# VAR=`trueorfalse default-value test-value`
function trueorfalse() {
    local default=$1
    local testval=$2

    [[ -z "$testval" ]] && { echo "$default"; return; }
    [[ "0 no false False FALSE" =~ "$testval" ]] && { echo "False"; return; }
    [[ "1 yes true True TRUE" =~ "$testval" ]] && { echo "True"; return; }
    echo "$default"
}