Относится к структурным шаблонам.

Используется для реализации слабосвязанной архитектуры.

Пример на PHP

class DatabaseConfiguration
{
    private string $host;
    private int $port;
    private string  $username;
    private string $password;

    public function __construct(string $host, int $port, string $username, string $password)
    {
        $this->host = $host;
        $this->port = $port;
        $this->username = $username;
        $this->password = $password;
    }

    public function getHost(): string
    {
        return $this->host;
    }

    public function getPort(): int
    {
        return $this->port;
    }

    public function getUsername(): string
    {
        return $this->username;
    }

    public function getPassword(): string
    {
        return $this->password;
    }
}

class DatabaseConnection
{
    private DatabaseConfiguration $configuration;

    public function __construct(DatabaseConfiguration $config)
    {
        $this->configuration = $config;
    }

    public function getDsn()
    {
        return sprintf(
            '%s:%s@%s:%d',
            $this->configuration->getUsername(),
            $this->configuration->getPassword(),
            $this->configuration->getHost(),
            $this->configuration->getPort()
        );
    }
}

Использование:

$config = new DatabaseConfiguration('localhost', 3306, 'user', '1234');
$connection = new DatabaseConnection($config);
$dsn = $connection->getDsn();

Пример на Go
 

package main

import "fmt"

type DatabaseConfiguration struct {
   host string
   port int
   username string
   password string
}

type DatabaseConnection struct {
   config *DatabaseConfiguration
}

func (c *DatabaseConfiguration) GetHost() string {
   return c.host
}

func (c *DatabaseConfiguration) GetPort() int {
   return c.port
}

func (c *DatabaseConfiguration) GetPassword() string {
   return c.password
}

func (c *DatabaseConfiguration) GetUsername() string {
   return c.username
}

func (c DatabaseConnection) GetDSN() string {
   return fmt.Sprintf(
      "%s:%s@%s:%d",
      c.config.GetUsername(),
      c.config.GetPassword(),
      c.config.GetHost(),
      c.config.GetPort(),
   )
}

func main() {
   dbConf :=DatabaseConfiguration{
      host: "localhost",
      port: 3306,
      password: "test",
      username: "test",
   }

   dbConn := DatabaseConnection{config: &dbConf}
   dbConn.GetDSN()
}

Источники:
http://designpatternsphp.readthedocs.io/ru/latest/Structural/DependencyInjection/README.html