# centos7下使用docker安装postgresql服务(带plpython3u扩展)

## 安装docker (使用root用户)

    1. 更新yum
        yum update
    2. 安装必要的依赖
        yum install -y yum-utils device-mapper-persistent-data lvm2
    3. 设置yum源(二选一)
        yum-config-manager --add-repo http://download.docker.com/linux/centos/docker-ce.repo（中央仓库）
        yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo（阿里仓库）
        
    4. 查看仓库中docker版本
        yum list docker-ce --showduplicates | sort -r
    5. 安装docker
        yum install docker-ce-版本号
        (例如: yum install docker-ce-18.03.1.ce)
    6. 启动docker并将docker加入开机启动
        1). systemctl start docker
        2). systemctl enable docker
        
    7. docker帮助
        docker --help
        docker 命令 --help

## 创建镜像

    1. 创建临时工作目录
    
        cd ~ && mkdir dockerTemp && cd dockerTemp

    2. 拷贝docker-entrypoint.sh 和 Dockerfile进临时工作目录
        (文件名大小写敏感, docker-entrypoint.sh 需要有可执行权限, chmod 777 docker-entrypoint.sh)
    
![pg001](./img/pgdocker_001.jpg)

<details>
<summary>docker-entrypoint.sh 内容</summary>

    #!/usr/bin/env bash
    set -Eeo pipefail
    # TODO swap to -Eeuo pipefail above (after handling all potentially-unset variables)
    
    # 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"
    }
    
    # check to see if this file is being run or sourced from another script
    _is_sourced() {
        # https://unix.stackexchange.com/a/215279
        [ "${#FUNCNAME[@]}" -ge 2 ] \
            && [ "${FUNCNAME[0]}" = '_is_sourced' ] \
            && [ "${FUNCNAME[1]}" = 'source' ]
    }
    
    # used to create initial postgres directories and if run as root, ensure ownership to the "postgres" user
    docker_create_db_directories() {
        local user; user="$(id -u)"
    
        mkdir -p "$PGDATA"
        chmod 700 "$PGDATA"
    
        # ignore failure since it will be fine when using the image provided directory; see also https://github.com/docker-library/postgres/pull/289
        mkdir -p /var/run/postgresql || :
        chmod 775 /var/run/postgresql || :
    
        # Create the transaction log directory before initdb is run so the directory is owned by the correct user
        if [ -n "$POSTGRES_INITDB_WALDIR" ]; then
            mkdir -p "$POSTGRES_INITDB_WALDIR"
            if [ "$user" = '0' ]; then
                find "$POSTGRES_INITDB_WALDIR" \! -user postgres -exec chown postgres '{}' +
            fi
            chmod 700 "$POSTGRES_INITDB_WALDIR"
        fi
    
        # allow the container to be started with `--user`
        if [ "$user" = '0' ]; then
            find "$PGDATA" \! -user postgres -exec chown postgres '{}' +
            find /var/run/postgresql \! -user postgres -exec chown postgres '{}' +
        fi
    }
    
    # initialize empty PGDATA directory with new database via 'initdb'
    # arguments to `initdb` can be passed via POSTGRES_INITDB_ARGS or as arguments to this function
    # `initdb` automatically creates the "postgres", "template0", and "template1" dbnames
    # this is also where the database user is created, specified by `POSTGRES_USER` env
    docker_init_database_dir() {
        # "initdb" is particular about the current user existing in "/etc/passwd", so we use "nss_wrapper" to fake that if necessary
        # see https://github.com/docker-library/postgres/pull/253, https://github.com/docker-library/postgres/issues/359, https://cwrap.org/nss_wrapper.html
        if ! getent passwd "$(id -u)" &> /dev/null && [ -e /usr/lib/libnss_wrapper.so ]; then
            export LD_PRELOAD='/usr/lib/libnss_wrapper.so'
            export NSS_WRAPPER_PASSWD="$(mktemp)"
            export NSS_WRAPPER_GROUP="$(mktemp)"
            echo "postgres:x:$(id -u):$(id -g):PostgreSQL:$PGDATA:/bin/false" > "$NSS_WRAPPER_PASSWD"
            echo "postgres:x:$(id -g):" > "$NSS_WRAPPER_GROUP"
        fi
    
        if [ -n "$POSTGRES_INITDB_WALDIR" ]; then
            set -- --waldir "$POSTGRES_INITDB_WALDIR" "$@"
        fi
    
        eval 'initdb --username="$POSTGRES_USER" --pwfile=<(echo "$POSTGRES_PASSWORD") '"$POSTGRES_INITDB_ARGS"' "$@"'
    
        # unset/cleanup "nss_wrapper" bits
        if [ "${LD_PRELOAD:-}" = '/usr/lib/libnss_wrapper.so' ]; then
            rm -f "$NSS_WRAPPER_PASSWD" "$NSS_WRAPPER_GROUP"
            unset LD_PRELOAD NSS_WRAPPER_PASSWD NSS_WRAPPER_GROUP
        fi
    }
    
    # print large warning if POSTGRES_PASSWORD is long
    # error if both POSTGRES_PASSWORD is empty and POSTGRES_HOST_AUTH_METHOD is not 'trust'
    # print large warning if POSTGRES_HOST_AUTH_METHOD is set to 'trust'
    # assumes database is not set up, ie: [ -z "$DATABASE_ALREADY_EXISTS" ]
    docker_verify_minimum_env() {
        # check password first so we can output the warning before postgres
        # messes it up
        if [ "${#POSTGRES_PASSWORD}" -ge 100 ]; then
            cat >&2 <<-'EOWARN'
    
                WARNING: The supplied POSTGRES_PASSWORD is 100+ characters.
    
                  This will not work if used via PGPASSWORD with "psql".
    
                  https://www.postgresql.org/message-id/flat/E1Rqxp2-0004Qt-PL%40wrigleys.postgresql.org (BUG #6412)
                  https://github.com/docker-library/postgres/issues/507
    
            EOWARN
        fi
        if [ -z "$POSTGRES_PASSWORD" ] && [ 'trust' != "$POSTGRES_HOST_AUTH_METHOD" ]; then
            # The - option suppresses leading tabs but *not* spaces. :)
            cat >&2 <<-'EOE'
                Error: Database is uninitialized and superuser password is not specified.
                       You must specify POSTGRES_PASSWORD to a non-empty value for the
                       superuser. For example, "-e POSTGRES_PASSWORD=password" on "docker run".
    
                       You may also use "POSTGRES_HOST_AUTH_METHOD=trust" to allow all
                       connections without a password. This is *not* recommended.
    
                       See PostgreSQL documentation about "trust":
                       https://www.postgresql.org/docs/current/auth-trust.html
            EOE
            exit 1
        fi
        if [ 'trust' = "$POSTGRES_HOST_AUTH_METHOD" ]; then
            cat >&2 <<-'EOWARN'
                ********************************************************************************
                WARNING: POSTGRES_HOST_AUTH_METHOD has been set to "trust". This will allow
                         anyone with access to the Postgres port to access your database without
                         a password, even if POSTGRES_PASSWORD is set. See PostgreSQL
                         documentation about "trust":
                         https://www.postgresql.org/docs/current/auth-trust.html
                         In Docker's default configuration, this is effectively any other
                         container on the same system.
    
                         It is not recommended to use POSTGRES_HOST_AUTH_METHOD=trust. Replace
                         it with "-e POSTGRES_PASSWORD=password" instead to set a password in
                         "docker run".
                ********************************************************************************
            EOWARN
        fi
    }
    
    # usage: docker_process_init_files [file [file [...]]]
    #    ie: docker_process_init_files /always-initdb.d/*
    # process initializer files, based on file extensions and permissions
    docker_process_init_files() {
        # psql here for backwards compatiblilty "${psql[@]}"
        psql=( docker_process_sql )
    
        echo
        local f
        for f; do
            case "$f" in
                *.sh)
                    # https://github.com/docker-library/postgres/issues/450#issuecomment-393167936
                    # https://github.com/docker-library/postgres/pull/452
                    if [ -x "$f" ]; then
                        echo "$0: running $f"
                        "$f"
                    else
                        echo "$0: sourcing $f"
                        . "$f"
                    fi
                    ;;
                *.sql)    echo "$0: running $f"; docker_process_sql -f "$f"; echo ;;
                *.sql.gz) echo "$0: running $f"; gunzip -c "$f" | docker_process_sql; echo ;;
                *.sql.xz) echo "$0: running $f"; xzcat "$f" | docker_process_sql; echo ;;
                *)        echo "$0: ignoring $f" ;;
            esac
            echo
        done
    }
    
    # Execute sql script, passed via stdin (or -f flag of pqsl)
    # usage: docker_process_sql [psql-cli-args]
    #    ie: docker_process_sql --dbname=mydb <<<'INSERT ...'
    #    ie: docker_process_sql -f my-file.sql
    #    ie: docker_process_sql <my-file.sql
    docker_process_sql() {
        local query_runner=( psql -v ON_ERROR_STOP=1 --username "$POSTGRES_USER" --no-password )
        if [ -n "$POSTGRES_DB" ]; then
            query_runner+=( --dbname "$POSTGRES_DB" )
        fi
    
        "${query_runner[@]}" "$@"
    }
    
    # create initial database
    # uses environment variables for input: POSTGRES_DB
    docker_setup_db() {
        if [ "$POSTGRES_DB" != 'postgres' ]; then
            POSTGRES_DB= docker_process_sql --dbname postgres --set db="$POSTGRES_DB" <<-'EOSQL'
                CREATE DATABASE :"db" ;
            EOSQL
            echo
        fi
    }
    
    # Loads various settings that are used elsewhere in the script
    # This should be called before any other functions
    docker_setup_env() {
        file_env 'POSTGRES_PASSWORD'
    
        file_env 'POSTGRES_USER' 'postgres'
        file_env 'POSTGRES_DB' "$POSTGRES_USER"
        file_env 'POSTGRES_INITDB_ARGS'
        # default authentication method is md5
        : "${POSTGRES_HOST_AUTH_METHOD:=md5}"
    
        declare -g DATABASE_ALREADY_EXISTS
        # look specifically for PG_VERSION, as it is expected in the DB dir
        if [ -s "$PGDATA/PG_VERSION" ]; then
            DATABASE_ALREADY_EXISTS='true'
        fi
    }
    
    # append POSTGRES_HOST_AUTH_METHOD to pg_hba.conf for "host" connections
    pg_setup_hba_conf() {
        {
            echo
            if [ 'trust' = "$POSTGRES_HOST_AUTH_METHOD" ]; then
                echo '# warning trust is enabled for all connections'
                echo '# see https://www.postgresql.org/docs/12/auth-trust.html'
            fi
            echo "host all all all $POSTGRES_HOST_AUTH_METHOD"
        } >> "$PGDATA/pg_hba.conf"
    }
    
    # start socket-only postgresql server for setting up or running scripts
    # all arguments will be passed along as arguments to `postgres` (via pg_ctl)
    docker_temp_server_start() {
        if [ "$1" = 'postgres' ]; then
            shift
        fi
    
        # internal start of server in order to allow setup using psql client
        # does not listen on external TCP/IP and waits until start finishes
        set -- "$@" -c listen_addresses='' -p "${PGPORT:-5432}"
    
        PGUSER="${PGUSER:-$POSTGRES_USER}" \
        pg_ctl -D "$PGDATA" \
            -o "$(printf '%q ' "$@")" \
            -w start
    }
    
    # stop postgresql server after done setting up user and running scripts
    docker_temp_server_stop() {
        PGUSER="${PGUSER:-postgres}" \
        pg_ctl -D "$PGDATA" -m fast -w stop
    }
    
    # check arguments for an option that would cause postgres to stop
    # return true if there is one
    _pg_want_help() {
        local arg
        for arg; do
            case "$arg" in
                # postgres --help | grep 'then exit'
                # leaving out -C on purpose since it always fails and is unhelpful:
                # postgres: could not access the server configuration file "/var/lib/postgresql/data/postgresql.conf": No such file or directory
                -'?'|--help|--describe-config|-V|--version)
                    return 0
                    ;;
            esac
        done
        return 1
    }
    
    _main() {
        # if first arg looks like a flag, assume we want to run postgres server
        if [ "${1:0:1}" = '-' ]; then
            set -- postgres "$@"
        fi
    
        if [ "$1" = 'postgres' ] && ! _pg_want_help "$@"; then
            docker_setup_env
            # setup data directories and permissions (when run as root)
            docker_create_db_directories
            if [ "$(id -u)" = '0' ]; then
                # then restart script as postgres user
                exec gosu postgres "$BASH_SOURCE" "$@"
            fi
    
            # only run initialization on an empty data directory
            if [ -z "$DATABASE_ALREADY_EXISTS" ]; then
                docker_verify_minimum_env
    
                # check dir permissions to reduce likelihood of half-initialized database
                ls /docker-entrypoint-initdb.d/ > /dev/null
    
                docker_init_database_dir
                pg_setup_hba_conf
    
                # PGPASSWORD is required for psql when authentication is required for 'local' connections via pg_hba.conf and is otherwise harmless
                # e.g. when '--auth=md5' or '--auth-local=md5' is used in POSTGRES_INITDB_ARGS
                export PGPASSWORD="${PGPASSWORD:-$POSTGRES_PASSWORD}"
                docker_temp_server_start "$@"
    
                docker_setup_db
                docker_process_init_files /docker-entrypoint-initdb.d/*
    
                docker_temp_server_stop
                unset PGPASSWORD
    
                echo
                echo 'PostgreSQL init process complete; ready for start up.'
                echo
            else
                echo
                echo 'PostgreSQL Database directory appears to contain a database; Skipping initialization'
                echo
            fi
        fi
    
        exec "$@"
    }
    
    if ! _is_sourced; then
        _main "$@"
    fi

</details>

<details>
<summary>Dockerfile 内容</summary>

    # FROM debian:buster-slim AS BASE1
    
    
    
    FROM buildpack-deps:buster
    
    # ensure local python is preferred over distribution python
    ENV PATH /usr/local/bin:$PATH
    
    # http://bugs.python.org/issue19846
    # > At the moment, setting "LANG=C" on a Linux system *fundamentally breaks Python 3*, and that's not OK.
    ENV LANG C.UTF-8
    
    # extra dependencies (over what buildpack-deps already includes)
    RUN apt-get update && apt-get install -y --no-install-recommends \
    		libbluetooth-dev \
    		tk-dev \
    		uuid-dev \
    	&& rm -rf /var/lib/apt/lists/*
    
    ENV GPG_KEY 0D96DF4D4110E5C43FBFB17F2D347EA6AA65421D
    ENV PYTHON_VERSION 3.7.7
    
    RUN set -ex \
    	\
    	&& wget -O python.tar.xz "https://www.python.org/ftp/python/${PYTHON_VERSION%%[a-z]*}/Python-$PYTHON_VERSION.tar.xz" \
    	&& wget -O python.tar.xz.asc "https://www.python.org/ftp/python/${PYTHON_VERSION%%[a-z]*}/Python-$PYTHON_VERSION.tar.xz.asc" \
    	&& export GNUPGHOME="$(mktemp -d)" \
    	&& gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys "$GPG_KEY" \
    	&& gpg --batch --verify python.tar.xz.asc python.tar.xz \
    	&& { command -v gpgconf > /dev/null && gpgconf --kill all || :; } \
    	&& rm -rf "$GNUPGHOME" python.tar.xz.asc \
    	&& mkdir -p /usr/src/python \
    	&& tar -xJC /usr/src/python --strip-components=1 -f python.tar.xz \
    	&& rm python.tar.xz \
    	\
    	&& cd /usr/src/python \
    	&& gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)" \
    	&& ./configure \
    		--build="$gnuArch" \
    		--enable-loadable-sqlite-extensions \
    		--enable-optimizations \
    		--enable-option-checking=fatal \
    		--enable-shared \
    		--with-system-expat \
    		--with-system-ffi \
    		--without-ensurepip \
    	&& make -j "$(nproc)" \
    # setting PROFILE_TASK makes "--enable-optimizations" reasonable: https://bugs.python.org/issue36044 / https://github.com/docker-library/python/issues/160#issuecomment-509426916
    		PROFILE_TASK='-m test.regrtest --pgo \
    			test_array \
    			test_base64 \
    			test_binascii \
    			test_binhex \
    			test_binop \
    			test_bytes \
    			test_c_locale_coercion \
    			test_class \
    			test_cmath \
    			test_codecs \
    			test_compile \
    			test_complex \
    			test_csv \
    			test_decimal \
    			test_dict \
    			test_float \
    			test_fstring \
    			test_hashlib \
    			test_io \
    			test_iter \
    			test_json \
    			test_long \
    			test_math \
    			test_memoryview \
    			test_pickle \
    			test_re \
    			test_set \
    			test_slice \
    			test_struct \
    			test_threading \
    			test_time \
    			test_traceback \
    			test_unicode \
    		' \
    	&& make install \
    	&& ldconfig \
    	\
    	&& find /usr/local -depth \
    		\( \
    			\( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
    			-o \
    			\( -type f -a \( -name '*.pyc' -o -name '*.pyo' \) \) \
    		\) -exec rm -rf '{}' + \
    	&& rm -rf /usr/src/python \
    	\
    	&& python3 --version
    
    # make some useful symlinks that are expected to exist
    RUN cd /usr/local/bin \
    	&& ln -s idle3 idle \
    	&& ln -s pydoc3 pydoc \
    	&& ln -s python3 python \
    	&& ln -s python3-config python-config
    
    # if this is called "PIP_VERSION", pip explodes with "ValueError: invalid truth value '<VERSION>'"
    ENV PYTHON_PIP_VERSION 20.1.1
    # https://github.com/pypa/get-pip
    ENV PYTHON_GET_PIP_URL https://github.com/pypa/get-pip/raw/eff16c878c7fd6b688b9b4c4267695cf1a0bf01b/get-pip.py
    ENV PYTHON_GET_PIP_SHA256 b3153ec0cf7b7bbf9556932aa37e4981c35dc2a2c501d70d91d2795aa532be79
    
    RUN set -ex; \
    	\
    	wget -O get-pip.py "$PYTHON_GET_PIP_URL"; \
    	echo "$PYTHON_GET_PIP_SHA256 *get-pip.py" | sha256sum --check --strict -; \
    	\
    	python get-pip.py \
    		--disable-pip-version-check \
    		--no-cache-dir \
    		"pip==$PYTHON_PIP_VERSION" \
    	; \
    	pip --version; \
    	\
    	find /usr/local -depth \
    		\( \
    			\( -type d -a \( -name test -o -name tests -o -name idle_test \) \) \
    			-o \
    			\( -type f -a \( -name '*.pyc' -o -name '*.pyo' \) \) \
    		\) -exec rm -rf '{}' +; \
    	rm -f get-pip.py
    
    RUN pip3 install shapely -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& pip3 install matplotlib -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& pip3 install short-text-sim -i http://dev.dp.sagacloud.cn:8082/repository/saga-pypi-group/simple --trusted-host dev.dp.sagacloud.cn \
    	&& pip3 install numpy -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& pip3 install vg -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& pip3 install networkx -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& pip3 install jieba -i https://pypi.tuna.tsinghua.edu.cn/simple \
    	&& cd /usr/local/lib/python3.7/site-packages \
    	&& git clone http://39.106.8.246:3003/chenhaiyang/relations.git
    
    
    # CMD ["python3"]
    
    
    # FROM debian:buster-slim
    
    RUN set -ex; \
    	if ! command -v gpg > /dev/null; then \
    		apt-get update; \
    		apt-get install -y --no-install-recommends \
    			gnupg \
    			dirmngr \
    		; \
    		rm -rf /var/lib/apt/lists/*; \
    	fi
    
    # explicitly set user/group IDs
    RUN set -eux; \
    	groupadd -r postgres --gid=999; \
    # https://salsa.debian.org/postgresql/postgresql-common/blob/997d842ee744687d99a2b2d95c1083a2615c79e8/debian/postgresql-common.postinst#L32-35
    	useradd -r -g postgres --uid=999 --home-dir=/var/lib/postgresql --shell=/bin/bash postgres; \
    # also create the postgres user's home directory with appropriate permissions
    # see https://github.com/docker-library/postgres/issues/274
    	mkdir -p /var/lib/postgresql; \
    	chown -R postgres:postgres /var/lib/postgresql
    
    # grab gosu for easy step-down from root
    # https://github.com/tianon/gosu/releases
    ENV GOSU_VERSION 1.12
    RUN set -eux; \
    	savedAptMark="$(apt-mark showmanual)"; \
    	apt-get update; \
    	apt-get install -y --no-install-recommends ca-certificates wget; \
    	rm -rf /var/lib/apt/lists/*; \
    	dpkgArch="$(dpkg --print-architecture | awk -F- '{ print $NF }')"; \
    	wget -O /usr/local/bin/gosu "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch"; \
    	wget -O /usr/local/bin/gosu.asc "https://github.com/tianon/gosu/releases/download/$GOSU_VERSION/gosu-$dpkgArch.asc"; \
    	export GNUPGHOME="$(mktemp -d)"; \
    	gpg --batch --keyserver hkps://keys.openpgp.org --recv-keys B42F6819007F00F88E364FD4036A9C25BF357DD4; \
    	gpg --batch --verify /usr/local/bin/gosu.asc /usr/local/bin/gosu; \
    	gpgconf --kill all; \
    	rm -rf "$GNUPGHOME" /usr/local/bin/gosu.asc; \
    	apt-mark auto '.*' > /dev/null; \
    	[ -z "$savedAptMark" ] || apt-mark manual $savedAptMark > /dev/null; \
    	apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false; \
    	chmod +x /usr/local/bin/gosu; \
    	gosu --version; \
    	gosu nobody true
    
    # make the "en_US.UTF-8" locale so postgres will be utf-8 enabled by default
    RUN set -eux; \
    	if [ -f /etc/dpkg/dpkg.cfg.d/docker ]; then \
    # if this file exists, we're likely in "debian:xxx-slim", and locales are thus being excluded so we need to remove that exclusion (since we need locales)
    		grep -q '/usr/share/locale' /etc/dpkg/dpkg.cfg.d/docker; \
    		sed -ri '/\/usr\/share\/locale/d' /etc/dpkg/dpkg.cfg.d/docker; \
    		! grep -q '/usr/share/locale' /etc/dpkg/dpkg.cfg.d/docker; \
    	fi; \
    	apt-get update; apt-get install -y --no-install-recommends locales; rm -rf /var/lib/apt/lists/*; \
    	localedef -i en_US -c -f UTF-8 -A /usr/share/locale/locale.alias en_US.UTF-8
    ENV LANG en_US.utf8
    
    RUN set -eux; \
    	apt-get update; \
    	apt-get install -y --no-install-recommends \
    # install "nss_wrapper" in case we need to fake "/etc/passwd" and "/etc/group" (especially for OpenShift)
    # https://github.com/docker-library/postgres/issues/359
    # https://cwrap.org/nss_wrapper.html
    		libnss-wrapper \
    # install "xz-utils" for .sql.xz docker-entrypoint-initdb.d files
    		xz-utils \
    	; \
    	rm -rf /var/lib/apt/lists/*
    
    RUN mkdir /docker-entrypoint-initdb.d
    
    RUN set -ex; \
    # pub   4096R/ACCC4CF8 2011-10-13 [expires: 2019-07-02]
    #       Key fingerprint = B97B 0AFC AA1A 47F0 44F2  44A0 7FCC 7D46 ACCC 4CF8
    # uid                  PostgreSQL Debian Repository
    	key='B97B0AFCAA1A47F044F244A07FCC7D46ACCC4CF8'; \
    	export GNUPGHOME="$(mktemp -d)"; \
    	gpg --batch --keyserver ha.pool.sks-keyservers.net --recv-keys "$key"; \
    	gpg --batch --export "$key" > /etc/apt/trusted.gpg.d/postgres.gpg; \
    	command -v gpgconf > /dev/null && gpgconf --kill all; \
    	rm -rf "$GNUPGHOME"; \
    	apt-key list
    
    ENV PG_MAJOR 12
    ENV PG_VERSION 12.3-1.pgdg100+1
    
    RUN set -ex; \
    	\
    # see note below about "*.pyc" files
    	export PYTHONDONTWRITEBYTECODE=1; \
    	\
    	dpkgArch="$(dpkg --print-architecture)"; \
    	case "$dpkgArch" in \
    		amd64 | arm64 | i386 | ppc64el) \
    # arches officialy built by upstream
    			echo "deb http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main $PG_MAJOR" > /etc/apt/sources.list.d/pgdg.list; \
    			apt-get update; \
    			;; \
    		*) \
    # we're on an architecture upstream doesn't officially build for
    # let's build binaries from their published source packages
    			echo "deb-src http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main $PG_MAJOR" > /etc/apt/sources.list.d/pgdg.list; \
    			\
    			case "$PG_MAJOR" in \
    				9.* | 10 ) ;; \
    				*) \
    # https://github.com/docker-library/postgres/issues/484 (clang-6.0 required, only available in stretch-backports)
    # TODO remove this once we hit buster+
    					echo 'deb http://deb.debian.org/debian buster-backports main' >> /etc/apt/sources.list.d/pgdg.list; \
    					;; \
    			esac; \
    			\
    			tempDir="$(mktemp -d)"; \
    			cd "$tempDir"; \
    			\
    			savedAptMark="$(apt-mark showmanual)"; \
    			\
    # build .deb files from upstream's source packages (which are verified by apt-get)
    			apt-get update; \
    			apt-get build-dep -y \
    				postgresql-common pgdg-keyring \
    				"postgresql-$PG_MAJOR=$PG_VERSION" \
    			; \
    			DEB_BUILD_OPTIONS="nocheck parallel=$(nproc)" \
    				apt-get source --compile \
    					postgresql-common pgdg-keyring \
    					"postgresql-$PG_MAJOR=$PG_VERSION" \
    			; \
    # we don't remove APT lists here because they get re-downloaded and removed later
    			\
    # reset apt-mark's "manual" list so that "purge --auto-remove" will remove all build dependencies
    # (which is done after we install the built packages so we don't have to redownload any overlapping dependencies)
    			apt-mark showmanual | xargs apt-mark auto > /dev/null; \
    			apt-mark manual $savedAptMark; \
    			\
    # create a temporary local APT repo to install from (so that dependency resolution can be handled by APT, as it should be)
    			ls -lAFh; \
    			dpkg-scanpackages . > Packages; \
    			grep '^Package: ' Packages; \
    			echo "deb [ trusted=yes ] file://$tempDir ./" > /etc/apt/sources.list.d/temp.list; \
    # work around the following APT issue by using "Acquire::GzipIndexes=false" (overriding "/etc/apt/apt.conf.d/docker-gzip-indexes")
    #   Could not open file /var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages - open (13: Permission denied)
    #   ...
    #   E: Failed to fetch store:/var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages  Could not open file /var/lib/apt/lists/partial/_tmp_tmp.ODWljpQfkE_._Packages - open (13: Permission denied)
    			apt-get -o Acquire::GzipIndexes=false update; \
    			;; \
    	esac; \
    	\
    	apt-get install -y --no-install-recommends postgresql-common; \
    	sed -ri 's/#(create_main_cluster) .*$/\1 = false/' /etc/postgresql-common/createcluster.conf; \
    	apt-get install -y --no-install-recommends \
    		"postgresql-$PG_MAJOR=$PG_VERSION" \
    	; \
    	\
    	rm -rf /var/lib/apt/lists/*; \
    	\
    	if [ -n "$tempDir" ]; then \
    # if we have leftovers from building, let's purge them (including extra, unnecessary build deps)
    		apt-get purge -y --auto-remove; \
    		rm -rf "$tempDir" /etc/apt/sources.list.d/temp.list; \
    	fi; \
    	\
    # some of the steps above generate a lot of "*.pyc" files (and setting "PYTHONDONTWRITEBYTECODE" beforehand doesn't propagate properly for some reason), so we clean them up manually (as long as they aren't owned by a package)
    	find /usr -name '*.pyc' -type f -exec bash -c 'for pyc; do dpkg -S "$pyc" &> /dev/null || rm -vf "$pyc"; done' -- '{}' +
    
    # make the sample config easier to munge (and "correct by default")
    RUN set -eux; \
    	dpkg-divert --add --rename --divert "/usr/share/postgresql/postgresql.conf.sample.dpkg" "/usr/share/postgresql/$PG_MAJOR/postgresql.conf.sample"; \
    	cp -v /usr/share/postgresql/postgresql.conf.sample.dpkg /usr/share/postgresql/postgresql.conf.sample; \
    	ln -sv ../postgresql.conf.sample "/usr/share/postgresql/$PG_MAJOR/"; \
    	sed -ri "s!^#?(listen_addresses)\s*=\s*\S+.*!\1 = '*'!" /usr/share/postgresql/postgresql.conf.sample; \
    	grep -F "listen_addresses = '*'" /usr/share/postgresql/postgresql.conf.sample
    
    RUN mkdir -p /var/run/postgresql && chown -R postgres:postgres /var/run/postgresql && chmod 2777 /var/run/postgresql
    
    ENV PATH $PATH:/usr/lib/postgresql/$PG_MAJOR/bin
    ENV PGDATA /var/lib/postgresql/data
    # this 777 will be replaced by 700 at runtime (allows semi-arbitrary "--user" values)
    RUN mkdir -p "$PGDATA" && chown -R postgres:postgres "$PGDATA" && chmod 777 "$PGDATA"
    VOLUME /var/lib/postgresql/data
    
    COPY docker-entrypoint.sh /usr/local/bin/
    RUN ln -s usr/local/bin/docker-entrypoint.sh / # backwards compat
    ENTRYPOINT ["docker-entrypoint.sh"]
    
    RUN apt-get update && apt-get install -y "postgresql-plpython3-12"
    
    # RUN echo 'CREATE EXTENSION plpythonu;' > /docker-entrypoint-initdb.d/plpythonu.sql
    
    EXPOSE 5432
    CMD ["postgres"]
</details>

    3. 文件内容说明
        1). docker-entrypoint.sh 是postgresql数据库的配置文件, 会拷贝到镜像内部使用
        2). Dockerfile是docker用来构建镜像的文件, 分为以下几个部分 
            1. 安装python3
            2. 安装python模块 vg, matplotlib, shapely, jieba, short-text-sim, networkx, numpy, git.sagacloud.cn上的算法包 
            3. 安装postgresql数据库
            4. 安装plpython3插件
    以上是镜像文件构建的准备工作

## 构建镜像

    1. 在dockerTemp临时工作目录内构建镜像
        docker build -t mypg:2 .
        其中-t是给镜像起个名字, mypg是名字, 2是版本号, 最后还有一个.表示基于当前目录进行构建镜像, 如果初次执行, 该命令耗时较长

## 运行镜像, 开启服务

    1. 查看镜像
        docker images
![pg002](./img/pgdocker_002.png)

    2. 运行
        mkdir -p /var/lib/postgresql/data
        docker run -d -e POSTGRES_PASSWORD=123456 --name pg12 -v /var/lib/postgresql/data:/var/lib/postgresql/data -p 5432:5432 mypg:1 postgres
        
        -d表示后台执行 (容器有个特性, 如果你run容器时执行的命令结束的话, 容器则自动结束) 
        -e表示设置环境变量(此处为pg数据库密码)
        --name是给容器起一个名字pg12
        -p 表示端口映射(本机端口:容器端口)
        -v 表示文件夹映射(本机目录:容器目录)  此处表示postgresql的数据文件存放目录放在本机中, 即便换了容器, 数据也是不变
        postgres 表示开启容器后执行的命令(postgres表示开启postgresql数据库)
    3. 检测
        docker ps         (查看当前运行中的容器 -a是查看所有)
        如下图所示, 服务已经开启, 可以测试连接数据库
![pg003](./img/pgdocker_003.jpg)

## 查看pg数据库数据文件的映射(volumes 映射)
    
    volumes文件映射的功能是让容器和本机的文件夹数据共享的机制
        docker inspect pg12 | grep Mounts -A 20
    
![pg004](./img/pgdocker_004.jpg)

## 其他常用命令
    
    1. 查看所有容器
        docker ps -a
    2. 查看所有镜像
        docker images
    3. 关闭容器, 开启容器
        docker start pg12
        docker stop pg12
    4. 删除容器
        docker rm pg12  (需要先关闭容器)
        docker rm -f pg12  (强制删除)
    5. 删除镜像
        docker rmi [镜像id]
    6. 进入容器
        docker exec -it pg12 /bin/bash
        (帮助: docker exec --help)
    7. 退出容器
        exit/quit
        ctrl + P + Q
        
## 导出和载入镜像
    镜像的导入和导出是方便镜像的分享和迁移, 如果服务器网路不好或者pull不下来镜像，只能在其它网路比较好的机器上pull下来
    镜像，导出成一个文件，再下载上传到网路不好的机器上，然后再从文件中导出来，这样在网络不好的机器上也能使用docker镜像
    
    1. 使用 docker images 找到需要导出的镜像
    2. 导出镜像, 将镜像保存为文件 
        docker save 镜像id > /root/myimage.tar
    3. 将镜像保存到另一台不能联网的服务器(需要安装过docker)上, 加载镜像
        docker load < /root/myimage.tar
    4. (选作) 有可能在新服务器上不能识别镜像的tag(名称:版本), 需要执行
        docker tag 镜像id 名称:版本       (例如: docker tag eb40dcf64078 nginx:latest)