MySQL/MariaDB is no longer supported

contrib/mariadb-stretch-err1071.md

-# MariaDB `Error 1071: Specified key was too long`
-
-## Background
-
-`tank` stores shows using it's name as primary key. Since this is a string it by default is
-mapped to a `VARCHAR(255)` at the database level.
-Some Linux distributions, i.e. Debian 9 (stretch) or Ubuntu 18.04 (bionic) have switched to
-the mySQL fork MariaDB. At least Debian und Ubuntu also switched to `utf8mb4` as
-the default character-set. This is an attempt to support Emoji's stored as UTF-8 characters in
-the database for applications like Wordpress.
-When using `utf8mb4` a `VARCHAR(255)` field can be up to 1021 bytes long. This exceeds the
-maximum length (767 bytes) for primary key indices on older version of the `innodb` file and row
-formats.
-
-## Possible Workarounds
-
-There are several possible workarounds for the problem:
-
- * Use `utf8` (not `utf8mb4`). Either by setting `store.db.Charset` to `utf8` or by
-   creating the database using this command:
-   ```mysql
-   create database tank CHARACTER SET utf8 COLLATE utf8_general_ci;
-   ```
-   Setting the character set using the daemon configuration is preferred because this also
-   makes sure that the database connection itself will use the correct settings as well.
-   Mind that this means you won't be able to use Emoji's in File Metadata. 😭
-
- * Debian has [backported](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=886756) some
-   changes to the MariaDB version in Debian Stretch. Because of this it is possible to switch
-   to the new innodb file and row format.
-   You can do this by adding the following to the `[mysqld]` section of
-   `/etc/mysql/mariadb.conf.d/50-server.cnf`:
-   ```ini
-   innodb_file_format        = Barracuda
-   innodb_file_per_table     = On
-   innodb_large_prefix       = On
-   innodb_default_row_format = dynamic
-   ```
-   As far as i can see Ubuntu did not add this patch to it's packages but starting with 10.2
-   MariaDB uses the new format by default. This means you can work around the issue by using
-   the packages provided by the [MariaDB Foundation](https://downloads.mariadb.org/mariadb/repositories/).
-
- * Consider switching to another DBMS:
-   * `tank` also works with postgres
-   * you may use the mySQL Community Packages from [Oracle](https://dev.mysql.com/doc/refman/5.7/en/linux-installation-debian.html)
-   * [Percona Server](https://www.percona.com/software/mysql-database/percona-server) is a drop-in
-     replacement for mySQL
-
- * If for some reason none of the above is applicable, as a last resort, you can apply the
-   patch below. This limits the length for show names to 191 characters which is just short
-   enough to not exceed the limit.
-
-   ```patch
-   diff --git a/store/types.go b/store/types.go
-   index 8576c7b..df99125 100644
-   --- a/store/types.go
-   +++ b/store/types.go
-   @@ -69,7 +69,7 @@ func (e ErrInvalidMetadataField) Error() string {
-    //******* Shows
-    
-    type Show struct {
-   -       Name      string    `json:"name" gorm:"primary_key"`
-   +       Name      string    `json:"name" gorm:"primary_key;size:191"`
-           CreatedAt time.Time `json:"created"`
-           UpdatedAt time.Time `json:"updated"`
-    }
-   @@ -169,7 +169,7 @@ type File struct {
-           ID        uint64        `json:"id" gorm:"primary_key"`
-           CreatedAt time.Time     `json:"created"`
-           UpdatedAt time.Time     `json:"updated"`
-   -       ShowName  string        `json:"show" gorm:"not null;index"`
-   +       ShowName  string        `json:"show" gorm:"not null;index;size:191"`
-           Show      Show          `json:"-" gorm:"association_foreignkey:Name"`
-           Source    FileSource    `json:"source" gorm:"embedded;embedded_prefix:source__"`
-           Metadata  FileMetadata  `json:"metadata" gorm:"embedded;embedded_prefix:metadata__"`
-   @@ -194,7 +194,7 @@ type Playlist struct {
-           ID        uint64          `json:"id" gorm:"primary_key"`
-           CreatedAt time.Time       `json:"created"`
-           UpdatedAt time.Time       `json:"updated"`
-   -       ShowName  string          `json:"show" gorm:"not null;index"`
-   +       ShowName  string          `json:"show" gorm:"not null;index;size:191"`
-           Show      Show            `json:"-" gorm:"association_foreignkey:Name"`
-           Entries   []PlaylistEntry `json:"entries,omitempty"`
-    }
-   ```

contrib/mysql/info.sql

-use tank;
-show tables;
-select * from __migrations__;
-describe shows;
-show index from shows;
-describe files;
-show index from files;
-describe import_logs;
-show index from import_logs;
-describe playlists;
-show index from playlists;
-describe playlist_entries;
-show index from playlist_entries;
-SELECT TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME,REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_SCHEMA = 'tank';

contrib/mysql/init.sql

-drop database tank;
-create database tank;
--- create database tank CHARACTER SET utf8 COLLATE utf8_general_ci;
--- create database tank CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;
-grant all privileges on tank.* to 'tank'@'%' identified by 'aura';
-use tank;

contrib/mysql/run_client.sh

-#!/bin/bash
-
-exec docker exec -it aura-mysql /bin/bash -c "cd /scripts; exec mysql"

contrib/mysql/run_server.sh

-#!/bin/bash
-
-case "$1" in
-  mariadb)
-    img="mariadb"
-    tag="10.1" ## mariadb in debian stretch
-    ;;
-  *)
-    img="mysql"
-    tag="5.7"
-    ;;
-esac
-
-SCRIPTS_D=$(realpath "${BASH_SOURCE%/*}/")
-exec docker run -it --rm --name aura-mysql -e MYSQL_INITDB_SKIP_TZINFO=1 -e MYSQL_ALLOW_EMPTY_PASSWORD=yes -v "$SCRIPTS_D:/scripts:ro" -p 3306:3306 "$img:$tag"

contrib/mysql/stop_server.sh

-#!/bin/bash
-
-exec docker stop aura-mysql

contrib/mysql/test-fk.sql

-use tank;
-
-/* should succeed */
-insert into shows (name) values ('test');
-
-/* should fail */
-insert into files (size) values(100);
-insert into files (show_name, size) values('invalid', 101);
-
-/* should succeed */
-insert into files (show_name, size) values('test', 101);
-insert into files (show_name, size) values('test', 102);
-select * from files;
-
-
-/* should fail */
-insert into playlists (created_at) values ('2018-06-17 02:38:17');
-
-/* should succeed */
-insert into playlists (created_at, show_name) values('2018-06-17 02:38:17', 'test');
-
-
-/* should fail */
-insert into playlist_entries (uri) values ('http://stream.example.com/live.mp3');
-insert into playlist_entries (playlist_id, uri) values (1, 'http://stream.example.com/live.mp3');
-insert into playlist_entries (playlist_id, line_num, uri) values (17, 1, 'http://stream.example.com/live.mp3');
-
-/* should succeed */
-insert into playlist_entries (playlist_id, line_num, uri) values (1, 1, 'http://stream.example.com/live.mp3');
-
-/* should fail */
-insert into playlist_entries (playlist_id, line_num, uri) values (1, 1, 'http://stream.example.com/other.mp3');
-insert into playlist_entries (playlist_id, line_num, file_id) values (1, 4, 23);
-
-/* should succeed */
-insert into playlist_entries (playlist_id, line_num, file_id) values (1, 4, 2);
-delete from files where id = 1;
-
-/* should fail */
-delete from files where id = 2;
-
-/* should succeed */
-delete from playlists where id = 1;
-delete from files where id = 2;