How to access DB config in CodeIgniter?

I don't have enough rep to comment on Matt Browne's correct answer but just adding a bit incase anyone forgets...

load the db driver like so first:

$this->load->database();

then you can easily access what you need:

$this->db->hostname
$this->db->username
$this->db->password
$this->db->database

Pretty much all the config values are accessible via $this->db (take a look at system/database/DB_driver.php).

That's what worked for me...none of the other suggestions here did.

As an example

$config = [ 
     'host'     => $this->db->hostname,
     'port'     => '3306',
     'username' => $this->db->username,
     'password' => $this->db->password,
     'database' => $this->db->database
];

For more details: https://stackoverflow.com/a/23666778/560114

In case you have multiple database connection groups defined in config/database.php, for eg :

  $db['dbname']['hostname'] = "localhost";
  $db['dbname']['username'] = "root";
  $db['dbname']['password'] = "root";
  $db['dbname']['database'] = "web_dbname";

  $db['dbname_readonly']['hostname'] = "localhost";
  $db['dbname_readonly']['username'] = "root";
  $db['dbname_readonly']['password'] = "root";
  $db['dbname_readonly']['database'] = "web_dbname_readonly";

If you want to use the connection params of any particular db in a controller or model:

  $db = $this->load->database('dbname');

If you want to use in a helper or library :

  $ci = &get_instance();
  $db = $ci->load->database('dbname');

The connection params will be available as $db->hostname, $db->username etc.

I stumbled across this, looking for a way to find all of the DB settings. Was not able to find a solution on-line, but found some useful code in system/database/DB.php

Here's my approach, get the contents of the entire database config:

    if ( ! file_exists($f = APPPATH.'config/'.ENVIRONMENT.'/database.php')
        && ! file_exists($f = APPPATH.'config/database.php'))
    {
        show_error('The configuration file database.php does not exist.');
    }

    include($f);

    // Use a NEW variable.  
    // Because $db is a reserved name!!
    $db_settings = $db;

    foreach($db_settings as $key => $value) {
        // .. do something with .. $this->database->load($key);
        // .. do something with .. $value['database'];
        // .. do something with .. $value['password'];
    }

You should be able to get at your configuration setting like this :

$this->config['env']