#!/bin/bash
# create dump for database and upload it to local mysql
# src=          server with source of db ( ip address or unix socket )
# dst=          server with destination of db  
# db=           db anme
# config_file=  mysql client config file
# Carefully! Ansible already provides values in quotes

#set -e

BY_TABLE=1      # if set to 1 it is create dump per table
# Longer but more reliable for large databases
REPLACE=0       # relace destionation database or not

DEFAULT_CONF=/root/.my.cnf # can set login and password from file
DEFAULT_CONF_USAGE=0

BASE_DIR=/opt/webdir
LOGDIR=$BASE_DIR/logs
[[ ! -d $LOGDIR ]] && mkdir -m 750 $LOGDIR
LOG_FILE=$LOGDIR/create_dbs.log

CACHE_DIR=$BASE_DIR/tmp
[[ ! -d $CACHE_DIR ]] && mkdir -p -m 700 $CACHE_DIR
CACHE_FILE=(mktemp $CACHE_DIR/.bx_dumpXXXXXX)

save_log(){
    message=$1

    printf "%-15s: [%s] %s\n" "$(date +%Y/%m/%d:%H:%M:%S)" "$$" "$message" >> $LOG_FILE
}

print_good(){
    local msg="${1}"
    local changed="${2:-true}"

    save_log "$msg"
    echo "{\"changed\": $changed, \"msg\": \"$msg\"}"
    [[ -f $CACHE_FILE ]] && rm -f $CACHE_FILE
    exit

}

print_error(){
    local msg="${1}"

    save_log "$msg"
    echo "{\"changed\": false, \"failed\": true, \"msg\": \"$msg\"}"
    [[ -f $CACHE_FILE ]] && rm -f $CACHE_FILE
    exit 1

}


# test mandatory option and print error if not exists
test_variables() {
    for desc in "src=$src" "dst=$dst" "db=$db" "config_file=$config_file"; do
        var=$(echo $desc | cut -d'=' -f1)
        val=$(echo $desc | cut -d'=' -f2)

        if [[ -z "$val" ]]; then
            # test config_file variable
            if [[  "$var" == "config_file" ]]; then
                if [[ ! -f "$DEFAULT_CONF" ]]; then
                    print_error "Not found client config file=$DEFAULT_CONF"
                fi
                DEFAULT_CONF_USAGE=1  
            else
                print_error "option $var= is mandatory, you must define it"
            fi
        fi
    done

    # replace existen DB
    REPLACE=0
    if [[ ( -n "$replace" ) && ( $(echo "$replace" | grep -wci 'yes') -gt 0 ) ]]; then
        REPLACE=1
    fi

    # dump database all at once or by table
    BY_TABLE=1
    if [[ ( -n "$by_table" ) && ( $(echo "$by_table" | grep -wci 'no') -gt 0 ) ]]; then
        BY_TABLE=0
    fi

    SITE_TYPE='link'    # if link - not dumped db, no dublicate 
    if [[ ( -n "$site_type" ) && ( $(echo "$site_type" | grep -wic 'kernel') -gt 0 ) ]]; then
        SITE_TYPE='kernel'
    fi
}

# create dump db and upload it to dest
dump_db() {
    save_log "Start recreate DBs on slave server, REPLACE=$REPLACE BY_TABLE=$BY_TABLE"  

    if [[ "$SITE_TYPE" == "link" ]]; then
        print_good "SITE_TYPE=$SITE_TYPE dump only for kernels. nothing to do" "false"
    fi

    # create command lines for mysqldump and mysql
    if [[ $DEFAULT_CONF_USAGE -eq 1 ]]; then
        src_mysqldump_cmd="mysqldump --defaults-file=$DEFAULT_CONF --opt --single-transaction"
        src_mysql_cmd="mysql --defaults-file=$DEFAULT_CONF"
        dst_mysql_cmd="mysql --defaults-file=$DEFAULT_CONF"
    else
        src_mysqldump_cmd="mysqldump --defaults-file=$config_file --opt --single-transaction"
        src_mysql_cmd="mysql --defaults-file=$config_file"
        dst_mysql_cmd="mysql --defaults-file=$config_file"
    fi

    # src is host address or local socket?
    if [[ $(echo $src | grep -c '^/') -gt 0 ]]; then
        src_mysql_cmd=$src_mysql_cmd" --socket=$src"
        src_mysqldump_cmd=$src_mysqldump_cmd" --socket=$src"
    else
        src_mysql_cmd=$src_mysql_cmd" --host=$src"
        src_mysqldump_cmd=$src_mysqldump_cmd" --host=$src"
    fi

    # dst is host address or local socket
    if [[ $(echo $dst | grep -c '^/') -gt 0 ]]; then
        dst_mysql_cmd=$dst_mysql_cmd" --socket=$dst"
    else
        dst_mysql_cmd=$dst_mysql_cmd" --host=$src"
    fi

    # final touch
    src_mysql_cmd=$src_mysql_cmd" $db"
    src_mysqldump_cmd=$src_mysqldump_cmd" $db"

    # test if database exists on dst server, if exist => exit 
    if_db=$($dst_mysql_cmd \
        -e "SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA WHERE SCHEMA_NAME = '$db'" 2>/dev/null)
    if [[ -n "$if_db" ]];then
        save_log "Found $db on server"
        if [[ $REPLACE -eq 0 ]]; then
            print_good "Database db=$db already exists. nothing to do!" "false"
        else
            save_log " REPLACE=$REPLACE and db will be replaced"
            $dst_mysql_cmd -e "drop database $db;" >> $LOG_FILE 2>&1 || \
                print_error "error occurred during deletion db=$db"
            if_db=0
        fi
    fi

    # create database
    save_log "create $db"
    $dst_mysql_cmd -e "create database $db;" >> $LOG_FILE 2>&1 || \
        print_error "error occurred during creation db=$db"

    # recovery database by mysqldump of it tables: one by one
    save_log "start recovery data from $db; BY_TABLE=$BY_TABLE"
    if [[ $BY_TABLE -eq 1 ]]; then
        #save_log "$src_mysql_cmd  -N -e \"show tables;\""
        # get list of tables from master
        $src_mysql_cmd  -N -e "show tables;" >$CACHE_FILE 2>> $LOG_FILE || \
            print_error "error occurred during getting list of tables db=$db"

        table_list=$(cat $CACHE_FILE | awk '{print $1}')
        [[ -z "$table_list" ]] && \
            print_good "there are no tables in database db=$db. nothing to do!" "false"

        # process table one by one, exit if error happened
        for table in $table_list; do
            save_log " $db - create table $table"
            #save_log " $src_mysqldump_cmd $table | $dst_mysql_cmd $db"
            $src_mysqldump_cmd $table | $dst_mysql_cmd $db >> $LOG_FILE 2>&1
            for rtn in ${PIPESTATUS[*]}; do
                [[ $rtn -gt 0 ]] && \
                    print_error "error occurred during recovery db=$db table=$table"
            done
            save_log "  $db - create table $table complete"
        done
        err=0

        # recovery database by mysqldump of whole database
    else
        $src_mysqldump_cmd | $dst_mysql_cmd >> $LOG_FILE 2>&1
        err=$?
    fi

    if [[ $err -gt 0 ]]; then
        print_error "error occurred during database db=$db recovery"
    else
        print_good "recovery database db=$db is complete"
    fi

    exit $err

}

# get options from file
source ${1}

test_variables

dump_db