mysql_confがない場合(mysql-community-serverを使っていて)

リポジトリの標準でないバージョンにmysqlを入れたいとき、mysql-community-serverを入れることはよくあると思います。
その関連でひっかかったエラーを忘備録として残します。(あんまりググっても引っかからなかったので)

## 遭遇したエラーと解決策
- エラー
    - `pip install flask-mysqldb`時に`OSError: mysql_config not found`
- 解決策
   - `sudo yum install mysql-community-devel`

## 遭遇したエラー
* # pip install flask-mysqldb
* 以下のエラーメッセージ

```
Collecting flask-mysqldb
  Using cached Flask-MySQLdb-0.2.0.tar.gz
Requirement already satisfied (use --upgrade to upgrade): Flask>=0.10 in /root/.pyenv/versions/3.5.1/lib/python3.5/site-packages (from flask-mysqldb)
Collecting mysqlclient (from flask-mysqldb)
  Using cached mysqlclient-1.3.9.tar.gz
    Complete output from command python setup.py egg_info:
    /bin/sh: mysql_config: command not found
    Traceback (most recent call last):
      File "<string>", line 20, in <module>
      File "/tmp/pip-build-xnry20_a/mysqlclient/setup.py", line 17, in <module>
        metadata, options = get_config()
      File "/tmp/pip-build-xnry20_a/mysqlclient/setup_posix.py", line 44, in get_config
        libs = mysql_config("libs_r")
      File "/tmp/pip-build-xnry20_a/mysqlclient/setup_posix.py", line 26, in mysql_config
        raise EnvironmentError("%s not found" % (mysql_config.path,))
    OSError: mysql_config not found

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-xnry20_a/mysqlclient
Y
```
* 重要なのはここです`OSError: mysql_config not found`
* たしかにない

```
# ll /usr/bin/mysql_config*
-rwxr-xr-x 1 root 8771007 Nov 28 20:30 /usr/bin/mysql_config_editor*
```

## 私の環境
* 以下の一連コマンドでmysql5.7.17をインストールしてた
    * `yum localinstall http://dev.mysql.com/get/mysql57-community-release-el7-7.noarch.rpm`
    * `yum -y install mysql-community-server`
* yum でなにがinstalledか確認

```
# yum list installed |grep mysql
mysql-community-client.x86_64    5.7.17-1.el7                          @mysql57-community
mysql-community-common.x86_64    5.7.17-1.el7                          @mysql57-community
mysql-community-libs.x86_64      5.7.17-1.el7                          @mysql57-community
mysql-community-server.x86_64    5.7.17-1.el7                          @mysql57-community
mysql57-community-release.noarch el7-7                                 @/mysql57-community-release-el7-7.noarch
```
* community-serverパッケージでinstall可能なもの
    * 長いんで一部抜粋

```
[root@localhost flaskr]# yum list available | grep mysql |grep community
mysql-community-client.i686               5.7.17-1.el7                   mysql57-community
mysql-community-common.i686               5.7.17-1.el7                   mysql57-community
mysql-community-devel.i686                5.7.17-1.el7                   mysql57-community
mysql-community-devel.x86_64              5.7.17-1.el7                   mysql57-community
mysql-community-embedded.i686             5.7.17-1.el7                   mysql57-community
mysql-community-embedded.x86_64           5.7.17-1.el7                   mysql57-community
mysql-community-embedded-compat.i686      5.7.17-1.el7                   mysql57-community
mysql-community-embedded-compat.x86_64    5.7.17-1.el7                   mysql57-community
mysql-community-embedded-devel.i686       5.7.17-1.el7                   mysql57-community
mysql-community-embedded-devel.x86_64     5.7.17-1.el7                   mysql57-community
mysql-community-libs.i686                 5.7.17-1.el7                   mysql57-community
mysql-community-libs-compat.i686          5.7.17-1.el7                   mysql57-community
mysql-community-libs-compat.x86_64        5.7.17-1.el7                   mysql57-community
mysql-community-release.noarch            el7-7                          mysql57-community
mysql-community-test.x86_64               5.7.17-1.el7                   mysql57-community
```
* mysql-community-devel.x86_64が一番あやしいのでyum installして解決
* 実際にありました

```
# ll /bin/mysql_config*
-rwxr-xr-x 1 root     840 Nov 28 20:24 /bin/mysql_config*
-rwxr-xr-x 1 root    4907 Nov 28 20:30 /bin/mysql_config-64*
-rwxr-xr-x 1 root 8771007 Nov 28 20:30 /bin/mysql_config_editor*
```