defmodule Ecto.Adapters.MyXQL do
@moduledoc """
Adapter module for MySQL.
It uses `MyXQL` for communicating to the database.
## Options
MySQL options split in different categories described
below. All options can be given via the repository
configuration:
### Connection options
* `:protocol` - Set to `:socket` for using UNIX domain socket, or `:tcp` for TCP
(default: `:socket`)
* `:socket` - Connect to MySQL via UNIX sockets in the given path.
* `:hostname` - Server hostname
* `:port` - Server port (default: 3306)
* `:username` - Username
* `:password` - User password
* `:database` - the database to connect to
* `:pool` - The connection pool module, may be set to `Ecto.Adapters.SQL.Sandbox`
* `:ssl` - Set to true if ssl should be used (default: false)
* `:ssl_opts` - A list of ssl options, see Erlang's `ssl` docs
* `:connect_timeout` - The timeout for establishing new connections (default: 5000)
* `:cli_protocol` - The protocol used for the mysql client connection (default: `"tcp"`).
This option is only used for `mix ecto.load` and `mix ecto.dump`,
via the `mysql` command. For more information, please check
[MySQL docs](https://dev.mysql.com/doc/en/connecting.html)
* `:socket_options` - Specifies socket configuration
* `:show_sensitive_data_on_connection_error` - show connection data and
configuration whenever there is an error attempting to connect to the
database
The `:socket_options` are particularly useful when configuring the size
of both send and receive buffers. For example, when Ecto starts with a
pool of 20 connections, the memory usage may quickly grow from 20MB to
50MB based on the operating system default values for TCP buffers. It is
advised to stick with the operating system defaults but they can be
tweaked if desired:
socket_options: [recbuf: 8192, sndbuf: 8192]
We also recommend developers to consult the `MyXQL.start_link/1` documentation
for a complete listing of all supported options.
### Storage options
* `:charset` - the database encoding (default: "utf8mb4")
* `:collation` - the collation order
* `:dump_path` - where to place dumped structures
### After connect callback
If you want to execute a callback as soon as connection is established
to the database, you can use the `:after_connect` configuration. For
example, in your repository configuration you can add:
after_connect: {MyXQL, :query!, ["SET variable = value", []]}
You can also specify your own module that will receive the MyXQL
connection as argument.
## Limitations
There are some limitations when using Ecto with MySQL that one
needs to be aware of.
### Engine
Tables created by Ecto are guaranteed to use InnoDB, regardless
of the MySQL version.
### UUIDs
MySQL does not support UUID types. Ecto emulates them by using
`binary(16)`.
### Read after writes
Because MySQL does not support RETURNING clauses in INSERT and
UPDATE, it does not support the `:read_after_writes` option of
`Ecto.Schema.field/3`.
### DDL Transaction
MySQL does not support migrations inside transactions as it
automatically commits after some commands like CREATE TABLE.
Therefore MySQL migrations does not run inside transactions.
## Old MySQL versions
### JSON support
MySQL introduced a native JSON type in v5.7.8, if your server is
using this version or higher, you may use `:map` type for your
column in migration:
add :some_field, :map
If you're using older server versions, use a `TEXT` field instead:
add :some_field, :text
in either case, the adapter will automatically encode/decode the
value from JSON.
### usec in datetime
Old MySQL versions did not support usec in datetime while
more recent versions would round or truncate the usec value.
Therefore, in case the user decides to use microseconds in
datetimes and timestamps with MySQL, be aware of such
differences and consult the documentation for your MySQL
version.
If your version of MySQL supports microsecond precision, you
will be able to utilize Ecto's usec types.
## Multiple Result Support
MyXQL supports the execution of queries that return multiple
results, such as text queries with multiple statements separated
by semicolons or stored procedures. These can be executed with
`Ecto.Adapters.SQL.query_many/4` or the `YourRepo.query_many/3`
shortcut.
Be default, these queries will be executed with the `:query_type`
option set to `:text`. To take advantage of prepared statements
when executing a stored procedure, set the `:query_type` option
to `:binary`.
"""
# Inherit all behaviour from Ecto.Adapters.SQL
use Ecto.Adapters.SQL, driver: :myxql
# And provide a custom storage implementation
@behaviour Ecto.Adapter.Storage
@behaviour Ecto.Adapter.Structure
## Custom MySQL types
@impl true
def loaders({:map, _}, type), do: [&json_decode/1, &Ecto.Type.embedded_load(type, &1, :json)]
def loaders(:map, type), do: [&json_decode/1, type]
def loaders(:float, type), do: [&float_decode/1, type]
def loaders(:boolean, type), do: [&bool_decode/1, type]
def loaders(:binary_id, type), do: [Ecto.UUID, type]
def loaders(_, type), do: [type]
defp bool_decode(<<0>>), do: {:ok, false}
defp bool_decode(<<1>>), do: {:ok, true}
defp bool_decode(<<0::size(1)>>), do: {:ok, false}
defp bool_decode(<<1::size(1)>>), do: {:ok, true}
defp bool_decode(0), do: {:ok, false}
defp bool_decode(1), do: {:ok, true}
defp bool_decode(x), do: {:ok, x}
defp float_decode(%Decimal{} = decimal), do: {:ok, Decimal.to_float(decimal)}
defp float_decode(x), do: {:ok, x}
defp json_decode(x) when is_binary(x), do: {:ok, MyXQL.json_library().decode!(x)}
defp json_decode(x), do: {:ok, x}
## Storage API
@impl true
def storage_up(opts) do
database = Keyword.fetch!(opts, :database) || raise ":database is nil in repository configuration"
opts = Keyword.delete(opts, :database)
charset = opts[:charset] || "utf8mb4"
check_existence_command = "SELECT TRUE FROM information_schema.schemata WHERE schema_name = '#{database}'"
case run_query(check_existence_command, opts) do
{:ok, %{num_rows: 1}} ->
{:error, :already_up}
_ ->
create_command =
~s(CREATE DATABASE `#{database}` DEFAULT CHARACTER SET = #{charset})
|> concat_if(opts[:collation], &"DEFAULT COLLATE = #{&1}")
case run_query(create_command, opts) do
{:ok, _} ->
:ok
{:error, %{mysql: %{name: :ER_DB_CREATE_EXISTS}}} ->
{:error, :already_up}
{:error, error} ->
{:error, Exception.message(error)}
{:exit, exit} ->
{:error, exit_to_exception(exit)}
end
end
end
defp concat_if(content, nil, _fun), do: content
defp concat_if(content, value, fun), do: content <> " " <> fun.(value)
@impl true
def storage_down(opts) do
database = Keyword.fetch!(opts, :database) || raise ":database is nil in repository configuration"
opts = Keyword.delete(opts, :database)
command = "DROP DATABASE `#{database}`"
case run_query(command, opts) do
{:ok, _} ->
:ok
{:error, %{mysql: %{name: :ER_DB_DROP_EXISTS}}} ->
{:error, :already_down}
{:error, %{mysql: %{name: :ER_BAD_DB_ERROR}}} ->
{:error, :already_down}
{:error, error} ->
{:error, Exception.message(error)}
{:exit, :killed} ->
{:error, :already_down}
{:exit, exit} ->
{:error, exit_to_exception(exit)}
end
end
@impl Ecto.Adapter.Storage
def storage_status(opts) do
database = Keyword.fetch!(opts, :database) || raise ":database is nil in repository configuration"
opts = Keyword.delete(opts, :database)
check_database_query = "SELECT schema_name FROM information_schema.schemata WHERE schema_name = '#{database}'"
case run_query(check_database_query, opts) do
{:ok, %{num_rows: 0}} -> :down
{:ok, %{num_rows: _num_rows}} -> :up
other -> {:error, other}
end
end
@impl true
def supports_ddl_transaction? do
false
end
@impl true
def lock_for_migrations(meta, opts, fun) do
%{opts: adapter_opts, repo: repo} = meta
if Keyword.fetch(adapter_opts, :pool_size) == {:ok, 1} do
Ecto.Adapters.SQL.raise_migration_pool_size_error()
end
opts = Keyword.merge(opts, [timeout: :infinity, telemetry_options: [schema_migration: true]])
{:ok, result} =
transaction(meta, opts, fn ->
lock_name = "\'ecto_#{inspect(repo)}\'"
try do
{:ok, _} = Ecto.Adapters.SQL.query(meta, "SELECT GET_LOCK(#{lock_name}, -1)", [], opts)
fun.()
after
{:ok, _} = Ecto.Adapters.SQL.query(meta, "SELECT RELEASE_LOCK(#{lock_name})", [], opts)
end
end)
result
end
@impl true
def insert(adapter_meta, schema_meta, params, on_conflict, returning, opts) do
%{source: source, prefix: prefix} = schema_meta
{_, query_params, _} = on_conflict
key = primary_key!(schema_meta, returning)
{fields, values} = :lists.unzip(params)
sql = @conn.insert(prefix, source, fields, [fields], on_conflict, [], [])
opts = if is_nil(Keyword.get(opts, :cache_statement)) do
[{:cache_statement, "ecto_insert_#{source}_#{length(fields)}"} | opts]
else
opts
end
case Ecto.Adapters.SQL.query(adapter_meta, sql, values ++ query_params, opts) do
{:ok, %{num_rows: 1, last_insert_id: last_insert_id}} ->
{:ok, last_insert_id(key, last_insert_id)}
{:ok, %{num_rows: 2, last_insert_id: last_insert_id}} ->
{:ok, last_insert_id(key, last_insert_id)}
{:error, err} ->
case @conn.to_constraints(err, source: source) do
[] -> raise err
constraints -> {:invalid, constraints}
end
end
end
defp primary_key!(%{autogenerate_id: {_, key, _type}}, [key]), do: key
defp primary_key!(_, []), do: nil
defp primary_key!(%{schema: schema}, returning) do
raise ArgumentError, "MySQL does not support :read_after_writes in schemas for non-primary keys. " <>
"The following fields in #{inspect schema} are tagged as such: #{inspect returning}"
end
defp last_insert_id(nil, _last_insert_id), do: []
defp last_insert_id(_key, 0), do: []
defp last_insert_id(key, last_insert_id), do: [{key, last_insert_id}]
@impl true
def structure_dump(default, config) do
table = config[:migration_source] || "schema_migrations"
path = config[:dump_path] || Path.join(default, "structure.sql")
with {:ok, versions} <- select_versions(table, config),
{:ok, contents} <- mysql_dump(config),
{:ok, contents} <- append_versions(table, versions, contents) do
File.mkdir_p!(Path.dirname(path))
File.write!(path, contents)
{:ok, path}
end
end
defp select_versions(table, config) do
case run_query(~s[SELECT version FROM `#{table}` ORDER BY version], config) do
{:ok, %{rows: rows}} -> {:ok, Enum.map(rows, &hd/1)}
{:error, %{mysql: %{name: :ER_NO_SUCH_TABLE}}} -> {:ok, []}
{:error, _} = error -> error
{:exit, exit} -> {:error, exit_to_exception(exit)}
end
end
defp mysql_dump(config) do
case run_with_cmd("mysqldump", config, ["--no-data", "--routines", config[:database]]) do
{output, 0} -> {:ok, output}
{output, _} -> {:error, output}
end
end
defp append_versions(_table, [], contents) do
{:ok, contents}
end
defp append_versions(table, versions, contents) do
{:ok,
contents <>
Enum.map_join(versions, &~s[INSERT INTO `#{table}` (version) VALUES (#{&1});\n])}
end
@impl true
def structure_load(default, config) do
path = config[:dump_path] || Path.join(default, "structure.sql")
args = ["--execute", "SET FOREIGN_KEY_CHECKS = 0; SOURCE #{path}; SET FOREIGN_KEY_CHECKS = 1"]
case run_with_cmd("mysql", config, args) do
{_output, 0} -> {:ok, path}
{output, _} -> {:error, output}
end
end
@impl true
def dump_cmd(args, opts \\ [], config) when is_list(config) and is_list(args),
do: run_with_cmd("mysqldump", config, args, opts)
## Helpers
defp run_query(sql, opts) do
{:ok, _} = Application.ensure_all_started(:ecto_sql)
{:ok, _} = Application.ensure_all_started(:myxql)
opts =
opts
|> Keyword.drop([:name, :log, :pool, :pool_size])
|> Keyword.put(:backoff_type, :stop)
|> Keyword.put(:max_restarts, 0)
task = Task.Supervisor.async_nolink(Ecto.Adapters.SQL.StorageSupervisor, fn ->
{:ok, conn} = MyXQL.start_link(opts)
value = MyXQL.query(conn, sql, [], opts)
GenServer.stop(conn)
value
end)
timeout = Keyword.get(opts, :timeout, 15_000)
case Task.yield(task, timeout) || Task.shutdown(task) do
{:ok, {:ok, result}} ->
{:ok, result}
{:ok, {:error, error}} ->
{:error, error}
{:exit, exit} ->
{:exit, exit}
nil ->
{:error, RuntimeError.exception("command timed out")}
end
end
defp exit_to_exception({%{__struct__: struct} = error, _})
when struct in [MyXQL.Error, DBConnection.Error],
do: error
defp exit_to_exception(reason), do: RuntimeError.exception(Exception.format_exit(reason))
defp run_with_cmd(cmd, opts, opt_args, cmd_opts \\ []) do
unless System.find_executable(cmd) do
raise "could not find executable `#{cmd}` in path, " <>
"please guarantee it is available before running ecto commands"
end
env =
if password = opts[:password] do
[{"MYSQL_PWD", password}]
else
[]
end
host = opts[:hostname] || System.get_env("MYSQL_HOST") || "localhost"
port = opts[:port] || System.get_env("MYSQL_TCP_PORT") || "3306"
protocol = opts[:cli_protocol] || System.get_env("MYSQL_CLI_PROTOCOL") || "tcp"
user_args =
if username = opts[:username] do
["--user", username]
else
[]
end
database_args =
if database = opts[:database] do
["--database", database]
else
[]
end
args =
[
"--host", host,
"--port", to_string(port),
"--protocol", protocol
] ++ user_args ++ database_args ++ opt_args
cmd_opts =
cmd_opts
|> Keyword.put_new(:stderr_to_stdout, true)
|> Keyword.update(:env, env, &Enum.concat(env, &1))
System.cmd(cmd, args, cmd_opts)
end
end
