sailing-analytics/configuration/environments_scripts/build-crontab-and-cp-files

#!/bin/bash

# Purpose: The first parameter is an image type. This script iterates over the image types' USER folders,
# concatenating all the symbolic links (referencing locations within configuration/crontabs) into one crontab
# file for each user. It also takes the name of the user containing a copy of the git repo as well as the name of the 
# dir within that user to go to. The created crontab for each user go into that user's home dir and are installed for
# that user too.
# Within these crontab stubs, are certain string literals, which are replaced: PATH_OF_HOME_DIR_TO_REPLACE is changed
# to the path of the home directory in which the crontab will be installed (ie. that user's home).
# Furthermore, within the users folder optional uid, gid and groups files an exist. uid should store the user's uid,
# gid the group id and groups should have secondary groups (one per line). The user is added to the secondary groups
# after all users are created.
# Useful files are also copied across from the "files" dir within each image type.
# Finally, the script ends by performing a deamon reload and reenabling all the systemd units in the files directory,
# so that the correct wants, requires, etc. are installed/linked. Any systemd units, within the mimicked filesystem,
# will be automatically enabled.
# For options, see the help below.
# This script should NOT be installed into /usr/local/bin. See the README for more.
. repo/usr/local/bin/imageupgrade_functions.sh
INSTALL_CRONTAB="true"
COPY_FILES="true"
CREATE_CRONTABS="true"
options='fnc'
while getopts $options option
do
    case $option in
        c) CREATE_CRONTABS="false";;
        f) COPY_FILES="false";;
        n) INSTALL_CRONTAB="false";;
        \?) echo "Invalid option"  # getops replaces unknown options with a question mark, so we have to escape the question mark.
            exit 4;;
    esac
done
shift $((OPTIND-1)) # shift the arguments along so there are no options in the arguments anymore.
if [[ "$#" -ne 1 ]]; then
    echo "$0 [ -f ] [ -n ] [ -c ] <ENVIRONMENT_TYPE>"
    echo ""
    echo "Use the f(iles) flag to disable file copying. Use the c(rontab) flag to disable the creation of users and the creation of crontab files for those users."
    echo "If the c flag is not used then the n(o install) flag can be used to setup the crontabs but not install them."
    exit 2
fi
ENV_TYPE="$1"
cd "$(dirname "$0")/${ENV_TYPE}"
if [[ -d "groups" ]]; then
    cd "groups"
    for group in * ; do
        [[ -e "$group" ]] || continue
        echo "CREATING GROUP $group"
        if [[ -e "$group"/gid ]]; then
            groupadd --gid $(cat "$group"/gid) "$group"
        else
            groupadd "$group"
        fi
    done
    cd ..
fi
if [[ -d "users" ]]; then
    cd "users"
    for dir in *; do
        [[ -d "$dir" ]] || continue
        USERNAME="$dir"
        user_UID=""
        user_GID=""
        echo "STARTING WORK ON USER $USERNAME"
        if [[ -f "$USERNAME"/uid ]]; then
            user_UID=$(cat "$USERNAME"/uid)
            echo "UID => $user_UID"
        fi
        if [[ -f "$USERNAME"/gid ]]; then
            user_GID=$(cat "$USERNAME"/gid)
            echo "GID => $user_GID"
            groupadd --gid "$user_GID" "$USERNAME"
            [[ "$?" -eq 0 ]] || echo "Group id or name already exists." >&2
        fi
        if [[ -n "$user_UID" && -n "$user_GID" ]]; then
            adduser --uid "$user_UID" --gid "$user_GID" "$USERNAME"
        elif [[ -n "$user_UID" ]]; then
            adduser --uid "$user_UID" "$USERNAME"
        elif [[ -n "$user_GID" ]]; then
            adduser --gid "$user_GID" "$USERNAME"
        else
            adduser "$USERNAME"
        fi
        id "$USERNAME"
        if [[ "$?" -eq 0 ]]; then
            HOME_DIR=$(eval echo $(printf "~%q" "$USERNAME"))   # The path to the home dir of the user whose cronjob will be installed.
            # Sets permissions of home dir.
            [[ -e "$USERNAME"/permissions ]] && chmod "$(cat "$USERNAME"/permissions)" "$HOME_DIR"
            if [[ "$CREATE_CRONTABS" == "true" ]]; then  # 9 is the exit code indicating the username already exists.
                # Clear the crontab file before assembling it from the snippets:
                > $HOME_DIR/crontab
                echo "# Note that this file should not be edited manually. Please instead make use of the build_crontab_and_setup_files command in imageupgrade_functions.sh">>"$HOME_DIR"/crontab
                echo "# which concatenates the crontabs found at users/*/* into this file. Please edit these crontab stubs in the git repo to make permanent changes.">>"$HOME_DIR"/crontab
                echo "">>"$HOME_DIR"/crontab
                for crontab in ${USERNAME}/crontab*; do
                    [[ -e $crontab ]] || continue
                    cat "${crontab}" | eval $( get_replacements_from_crontab_filename_as_sed_command "${crontab}" ) >> $HOME_DIR/crontab
                    echo "">> $HOME_DIR/crontab
                done
                chown "$USERNAME":"$USERNAME" $HOME_DIR/crontab
                sed -i "s|PATH_OF_HOME_DIR_TO_REPLACE|${HOME_DIR}|g" "$HOME_DIR"/crontab # Sets the correct path to the home dir of the user whose crontab will be installed.
                sed -i '/^$/d' $HOME_DIR/crontab # purges random empty lines.
                echo "">>$HOME_DIR/crontab  # Adds a newline
                if [[ "$INSTALL_CRONTAB" == "true" ]]; then
                    crontab -u ${USERNAME} $HOME_DIR/crontab # Install the crontab in the given user's home dir.
                fi
            fi
        fi
        echo "****** finished user ******"
    done
    # Add to groups after all the groups exist.
    for dir in *; do
        [[ -d "$dir" ]] || continue
        USERNAME="$dir"
        [[ -e "$USERNAME"/groups ]] || continue
        echo "ADDING $USERNAME TO THE GROUPS SPECIFIED IN THEIR 'groups' FILE"
        for group in $(cat "$USERNAME"/groups); do
            gpasswd --add "$USERNAME" "$group"
        done
    done
    cd .. # exits users folder, which is essential for the next commands
fi
# Add users to groups, specified in ENVIRONMENT_TYPE/groups/GROUP/users. Used if groups exist which aren't directly related to a user.
if [[ -d "groups" ]]; then
    cd "groups"
    for group in * ; do
        [[ -e "$group"/users ]] || continue
        echo "ADDING USERS IN 'users' FILE TO GROUP $group"
        for user in $(cat "$group"/users); do
            gpasswd -a "$user" "$group"
        done
    done
    cd ..
fi
if [[ "$COPY_FILES" == "true" && -d "files" ]]; then
    cd "files"
    \cp --remove-destination -rL * /   # copies all files accross, realising any symbolic links. The backslash escapes the alias cp -i.
    systemctl daemon-reload
    for unit in etc/systemd/system/*; do
        [[ -f "$unit" ]] || continue
        systemctl reenable /"${unit}" # to recreate all the dependency links.
    done
    cd ..
fi