Struct DbConfig 

pub struct DbConfig {
    pub database_url: String,
    pub min_connections: u32,
    pub max_connections: u32,
    pub acquire_timeout: Duration,
    pub idle_timeout: Duration,
    pub test_before_acquire: bool,
}

Settings used to establish a connection with a database, regardless of the engine. All the values can be initialized with DbConfig::init_for() method, that uses environment variables to setup all of them, otherwise all have default values, except the string connection.

Fields

database_url: String

Database URL, initialized with the DATABASE_URL env

min_connections: u32

Min connections created at start-up, value set with MIN_CONNECTIONS env, default 1

max_connections: u32

Max connections allowed, value set with MAX_CONNECTIONS env, default 10

acquire_timeout: Duration

Time allowed to acquire a connection, value set with ACQUIRE_TIMEOUT_MS env, default 750 milliseconds

idle_timeout: Duration

Max time a connection can be idle, value set with IDLE_TIMEOUT_SEC env, default 300 sec (5 min). Any connection that remains in the idle queue longer than this will be closed.

test_before_acquire: bool

Whether to test before test the connection at start-up or not, value set with TEST_BEFORE_ACQUIRE env, default to false

Implementations

impl DbConfig

pub fn init_for(env: &Environment) -> Result<Self>

Init the object with env passed, and the rest of the attributes reading its corresponding environment variable, otherwise use a default value.

The database string is saved in self.database_url with the value found at the DATABASE_URL environment value, that it’s the only one required (there is no default value). If env passed is Environment::Test the prefix _test is added to the string connection, to avoid using by mistake prod/local databases, unless the string already ends with the prefix, or the string has connection arguments (the ? symbol in the string).

Examples

use std::env;
use server_env_config::db::DbConfig;
use server_env_config::env::Environment;

// Configurations should be actually set by the OS environment
env::set_var("DATABASE_URL", "postgresql://user:pass@localhost/db");
env::set_var("MAX_CONNECTIONS", "50");
env::set_var("IDLE_TIMEOUT_SEC", "60");

let db = DbConfig::init_for(&Environment::Local).unwrap();

assert_eq!(db.database_url, "postgresql://user:pass@localhost/db");
assert_eq!(db.max_connections, 50);
// All settings except DATABASE_URL have default values if env variables are not set
assert_eq!(db.min_connections, 1);
assert!(!db.test_before_acquire);

env::remove_var("DATABASE_URL"); // if not set, DbConfig cannot be initialized
let db = DbConfig::init_for(&Environment::Local);
assert!(db.is_err());

Trait Implementations

impl Clone for DbConfig

fn clone(&self) -> DbConfig

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DbConfig

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl ToString for DbConfig

fn to_string(&self) -> String

This to_string() implementation prints out all the config values in .env format, using as key the environment variable used to set-up the config, even if the configuration was set in another way, e.g. using a default value.