clone-mongo-db

#!/usr/bin/env bash
#
#
# Clones a MongoDB database.
#
# Usage:
#   clone-mongo-db <db-name> <clone-name>
#   clone-mongo-db -h
#
# Arguments:
#   <db-name>         Name of the database to clone.
#
#   <clone-name>      Name of the clone database.
#
# Options:
#   -h                Display help and exit.
#
#
# Exit codes:
#   0 - success
#   1 - incorrect usage
#   2 - MongoDB error


# exit codes
SUCCESS=0
INCORRECT_USAGE=1
MONGO_ERROR=2

#######################################
# Display help message.
# Arguments:
#   None
# Outputs:
#   Writes help message to stdout
#######################################
showhelp() {
cat << EOF
Usage:
    clone-mongo-db <db-name> <clone-name>
    clone-mongo-db -h

Clones a MongoDB database.

Arguments:
    <db-name>       Name of the database to clone.

    <clone-name>    Name of the clone database.

Options:
    -h              Display help and exit.
EOF
}


#######################################
# Asserts the given command runs successfully.
# Arguments:
#   $1 - message to print before running command
#   $2 - command to run
#   $3 - error message to print on failure
#   $4 - exit code to use on failure
#   $5 - success message to print on success
# Outputs:
#   Writes error message to stdout
#######################################
assert_success() {
    echo $1
    eval $2
    if [[ $? -ne 0 ]]; then
        echo "$3"
        echo -e "\nGoodbye..."
        exit $4
    fi
    echo -e $5
}

while getopts "h" flag; do
    case "${flag}" in
        h) showhelp; exit ${SUCCESS} ;;
        ?) showhelp; exit ${INCORRECT_USAGE} ;;
    esac
done
shift $((OPTIND - 1))

# Ensure that 2 arguments are given
if [[ $# -ne 2 ]]; then
    exit ${INCORRECT_USAGE}
fi

# Assign MONGO_PASS and MONGO_USER environment variables
[[ -z "${MONGO_USER}" ]] && read -p "Enter MongoDB username: " MONGO_USER
[[ -z "${MONGO_PASS}" ]] && read -p "Enter MongoDB password: " MONGO_PASS

assert_success "Cloning database $1 to $2..." \
    "mongodump --archive --authenticationDatabase=admin --db=$1 --authenticationMechanism=SCRAM-SHA-256 --username='${MONGO_USER}' --password='${MONGO_PASS}' | mongorestore --archive --authenticationDatabase=admin --nsFrom='$1.*' --nsTo='$2.*' --authenticationMechanism=SCRAM-SHA-256 --username='${MONGO_USER}' --password='${MONGO_PASS}'" \
    "Failed to clone database $1 to $2." \
    ${MONGO_ERROR} \
    "Successfully cloned database $1 to $2."


exit ${SUCCESS}