摘要:其中从参数第个位置取字符,如为,则取字符,若条件为真,通过命令重置参数,添加前缀,即经过处理后变为。
Docker Hub中有很多好用的Docker镜像,但镜像到底如何工作、能做什么、怎么做值得我们研究,如下所示为MySQL官方镜像的docker-entrypoint.sh脚本分析:
#!/bin/bash set -eo pipefail shopt -s nullglob ################################################################ # 若启动命令时附加了参数,则在参数前添加mysqld,如$0 -f test,则经过此代码处理后, # $@参数变mysqld -f test。其中${1:0:1}从$1参数第0个位置取1字符,如$1为-f,则 # 取"-"字符,若条件为真,通过set命令重置$@参数,添加mysqld前缀,即经过处理后$1变 # 为mysqld。 ################################################################ # if command starts with an option, prepend mysqld if [ "${1:0:1}" = "-" ]; then set -- mysqld "$@" fi # 解析参数,是否是获取帮助信息参数,并设置wantHelp值 ##################################################### # skip setup if they want an option that stops mysqld wantHelp= for arg; do case "$arg" in -"?"|--help|--print-defaults|-V|--version) wantHelp=1 break ;; esac done ############################# # 从文件中读取变量值 ############################# # usage: file_env VAR [DEFAULT] # ie: file_env "XYZ_DB_PASSWORD" "example" # (will allow for "$XYZ_DB_PASSWORD_FILE" to fill in the value of # "$XYZ_DB_PASSWORD" from a file, especially for Docker"s secrets feature) file_env() { local var="$1" local fileVar="${var}_FILE" local def="${2:-}" if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then echo >&2 "error: both $var and $fileVar are set (but are exclusive)" exit 1 fi local val="$def" if [ "${!var:-}" ]; then val="${!var}" elif [ "${!fileVar:-}" ]; then val="$(< "${!fileVar}")" fi export "$var"="$val" unset "$fileVar" } ########################################################################### # 运行mysqld --help --verbose --help 2>&1 >/dev/null命令, # 此命令会检查配置文件,若配置文件没问题,则成功,不成功则输出错误信息,及if中添 # 加!取不成功。 ########################################################################### _check_config() { toRun=( "$@" --verbose --help ) if ! errors="$("${toRun[@]}" 2>&1 >/dev/null)"; then cat >&2 <<-EOM ERROR: mysqld failed while attempting to check config command was: "${toRun[*]}" $errors EOM exit 1 fi } # 1. $1参数为mysqld 以及 wanthelp 参数为空 以及root用户,执行此代码; # 2. _check_config检查配置文件是否正确 # 3. 获取DATADIR目录,执行mysqld --verbose --help --log-bin-index=/tmp/tmp.4SyApJWeIo| # awk "$1 == """datadir""" { print $2; exit }" # 4. 创建并修改目录权限 # 5. 执行exec gosu mysql docker-entrypoint.sh "$@",即重新以mysql用户再次调用脚 # 本 # allow the container to be started with `--user` if [ "$1" = "mysqld" -a -z "$wantHelp" -a "$(id -u)" = "0" ]; then _check_config "$@" DATADIR="$(_get_config "datadir" "$@")" mkdir -p "$DATADIR" chown -R mysql:mysql "$DATADIR" exec gosu mysql "$BASH_SOURCE" "$@" fi # 1. $1参数为mysqld 以及 wanthelp 参数为空,执行此代码,及exec gosu会执行此代码; if [ "$1" = "mysqld" -a -z "$wantHelp" ]; then # 2. 仍然检查配置文件以及获取datadir目录 # still need to check config, container may have started with --user _check_config "$@" # Get config DATADIR="$(_get_config "datadir" "$@")" # 3. 若mysql数据库未创建,则执行本段逻辑 if [ ! -d "$DATADIR/mysql" ]; then # 4. 检查是否设置变量,如root密码、允许root密码为空亦或者随机密码 file_env "MYSQL_ROOT_PASSWORD" if [ -z "$MYSQL_ROOT_PASSWORD" -a -z "$MYSQL_ALLOW_EMPTY_PASSWORD" -a -z "$MYSQL_RANDOM_ROOT_PASSWORD" ]; then echo >&2 "error: database is uninitialized and password option is not specified " echo >&2 " You need to specify one of MYSQL_ROOT_PASSWORD, MYSQL_ALLOW_EMPTY_PASSWORD and MYSQL_RANDOM_ROOT_PASSWORD" exit 1 fi # 5. 创建目录 mkdir -p "$DATADIR" # 6. 执行mysqld命令初始化数据库 echo "Initializing database" "$@" --initialize-insecure echo "Database initialized" # 7. command -v mysql_ssl_rsa_setup检查命令是否可执行,以及是否存在 # server-key.pem文件,若不存在,则生成证书 if command -v mysql_ssl_rsa_setup > /dev/null && [ ! -e "$DATADIR/server-key.pem" ]; then # https://github.com/mysql/mysql-server/blob/23032807537d8dd8ee4ec1c4d40f0633cd4e12f9/packaging/deb-in/extra/mysql-systemd-start#L81-L84 echo "Initializing certificates" mysql_ssl_rsa_setup --datadir="$DATADIR" echo "Certificates initialized" fi # 8. 获取socket值并启动mysql SOCKET="$(_get_config "socket" "$@")" "$@" --skip-networking --socket="${SOCKET}" & pid="$!" # 9. 设置mysql变量(列表形式),而后可以${mysql[@]}调用 mysql=( mysql --protocol=socket -uroot -hlocalhost --socket="${SOCKET}" ) # 10. 运行30次,验证mysql是否已经启动完毕 for i in {30..0}; do if echo "SELECT 1" | "${mysql[@]}" &> /dev/null; then break fi echo "MySQL init process in progress..." sleep 1 done # 11. 若i为0值,则表明mysql启动失败 if [ "$i" = 0 ]; then echo >&2 "MySQL init process failed." exit 1 fi # 11. 解决时区bug if [ -z "$MYSQL_INITDB_SKIP_TZINFO" ]; then # sed is for https://bugs.mysql.com/bug.php?id=20545 mysql_tzinfo_to_sql /usr/share/zoneinfo | sed "s/Local time zone must be set--see zic manual page/FCTY/" | "${mysql[@]}" mysql fi # 12. 生成root随机密码 if [ ! -z "$MYSQL_RANDOM_ROOT_PASSWORD" ]; then export MYSQL_ROOT_PASSWORD="$(pwgen -1 32)" echo "GENERATED ROOT PASSWORD: $MYSQL_ROOT_PASSWORD" fi # 13. 若MYSQL_ROOT_HOST不为空亦或者不为localhost,则创建root用户 rootCreate= # default root to listen for connections from anywhere file_env "MYSQL_ROOT_HOST" "%" if [ ! -z "$MYSQL_ROOT_HOST" -a "$MYSQL_ROOT_HOST" != "localhost" ]; then # no, we don"t care if read finds a terminating character in this heredoc # https://unix.stackexchange.com/questions/265149/why-is-set-o-errexit-breaking-this-read-heredoc-expression/265151#265151 read -r -d "" rootCreate <<-EOSQL || true CREATE USER "root"@"${MYSQL_ROOT_HOST}" IDENTIFIED BY "${MYSQL_ROOT_PASSWORD}" ; GRANT ALL ON *.* TO "root"@"${MYSQL_ROOT_HOST}" WITH GRANT OPTION ; EOSQL fi # 14. 为"root"@"localhost"重置root密码 # 使用$rootCreate创建root "${mysql[@]}" <<-EOSQL -- What"s done in this file shouldn"t be replicated -- or products like mysql-fabric won"t work SET @@SESSION.SQL_LOG_BIN=0; SET PASSWORD FOR "root"@"localhost"=PASSWORD("${MYSQL_ROOT_PASSWORD}") ; GRANT ALL ON *.* TO "root"@"localhost" WITH GRANT OPTION ; ${rootCreate} DROP DATABASE IF EXISTS test ; FLUSH PRIVILEGES ; EOSQL # 15. 已设置root密码,故mysql需加上root密码 if [ ! -z "$MYSQL_ROOT_PASSWORD" ]; then mysql+=( -p"${MYSQL_ROOT_PASSWORD}" ) fi # 16. 若配置了MYSQL_DATABASE变量,则创建 file_env "MYSQL_DATABASE" if [ "$MYSQL_DATABASE" ]; then echo "CREATE DATABASE IF NOT EXISTS `$MYSQL_DATABASE` ;" | "${mysql[@]}" mysql+=( "$MYSQL_DATABASE" ) fi # 17. 在数据库内创建用户 file_env "MYSQL_USER" file_env "MYSQL_PASSWORD" if [ "$MYSQL_USER" -a "$MYSQL_PASSWORD" ]; then echo "CREATE USER "$MYSQL_USER"@"%" IDENTIFIED BY "$MYSQL_PASSWORD" ;" | "${mysql[@]}" if [ "$MYSQL_DATABASE" ]; then echo "GRANT ALL ON `$MYSQL_DATABASE`.* TO "$MYSQL_USER"@"%" ;" | "${mysql[@]}" fi echo "FLUSH PRIVILEGES ;" | "${mysql[@]}" fi # 18. 执行/docker-entrypoint-initdb.d目录下面的脚本,包含shell、sql echo for f in /docker-entrypoint-initdb.d/*; do case "$f" in *.sh) echo "$0: running $f"; . "$f" ;; *.sql) echo "$0: running $f"; "${mysql[@]}" < "$f"; echo ;; *.sql.gz) echo "$0: running $f"; gunzip -c "$f" | "${mysql[@]}"; echo ;; *) echo "$0: ignoring $f" ;; esac echo done # 19. 设置root密码是否过期 if [ ! -z "$MYSQL_ONETIME_PASSWORD" ]; then "${mysql[@]}" <<-EOSQL ALTER USER "root"@"%" PASSWORD EXPIRE; EOSQL fi # 20. kill -s TERM "$pid" 杀掉mysql进程,执行成功则返回0,而!kill取反,即kill成 # 功后才执行后面的!wait命令 if ! kill -s TERM "$pid" || ! wait "$pid"; then echo >&2 "MySQL init process failed." exit 1 fi # 21. 初始化成功后,再次启动 echo echo "MySQL init process done. Ready for start up." echo fi fi # 22. 正式启动数据库 exec "$@"
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摘要:其中从参数第个位置取字符,如为,则取字符,若条件为真,通过命令重置参数,添加前缀,即经过处理后变为。 Docker Hub中有很多好用的Docker镜像,但镜像到底如何工作、能做什么、怎么做值得我们研究,如下所示为MySQL官方镜像的docker-entrypoint.sh脚本分析: #!/bin/bash set -eo pipefail shopt -s nullglob ###...
摘要:其中从参数第个位置取字符,如为,则取字符,若条件为真,通过命令重置参数,添加前缀,即经过处理后变为。 Docker Hub中有很多好用的Docker镜像,但镜像到底如何工作、能做什么、怎么做值得我们研究,如下所示为MySQL官方镜像的docker-entrypoint.sh脚本分析: #!/bin/bash set -eo pipefail shopt -s nullglob ###...
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