Struct PoolConfig 

pub struct PoolConfig {

    pub host: String,
    pub port: u16,
    pub user: String,
    pub database: String,
    pub password: Option<String>,
    pub max_connections: usize,
    pub min_connections: usize,
    pub idle_timeout: Duration,
    pub acquire_timeout: Duration,
    pub connect_timeout: Duration,
    pub max_lifetime: Option<Duration>,
    pub test_on_acquire: bool,
    pub tls_mode: TlsMode,
    pub tls_ca_cert_pem: Option<Vec<u8>>,
    pub mtls: Option<TlsConfig>,
    pub gss_token_provider: Option<GssTokenProvider>,
    pub gss_token_provider_ex: Option<GssTokenProviderEx>,
    pub gss_connect_retries: usize,
    pub gss_retry_base_delay: Duration,
    pub gss_circuit_breaker_threshold: usize,
    pub gss_circuit_breaker_window: Duration,
    pub gss_circuit_breaker_cooldown: Duration,
    pub auth_settings: AuthSettings,
    pub gss_enc_mode: GssEncMode,
}

Configuration for a PostgreSQL connection pool.

Use the builder pattern to customise settings:

use std::time::Duration;
use qail_pg::driver::pool::PoolConfig;
let config = PoolConfig::new("localhost", 5432, "app", "mydb")
    .password("secret")
    .max_connections(20)
    .acquire_timeout(Duration::from_secs(5));

Fields

host: String

PostgreSQL server hostname or IP address.

port: u16

PostgreSQL server port (default: 5432).

user: String

Database role / user name.

database: String

Target database name.

password: Option<String>

Optional password for authentication.

max_connections: usize

Hard upper limit on simultaneous connections (default: 10).

min_connections: usize

Minimum idle connections kept warm in the pool (default: 1).

idle_timeout: Duration

Close idle connections after this duration (default: 10 min).

acquire_timeout: Duration

Maximum time to wait when acquiring a connection (default: 30s).

connect_timeout: Duration

TCP connect timeout for new connections (default: 10s).

max_lifetime: Option<Duration>

Optional maximum lifetime of any connection in the pool.

test_on_acquire: bool

When true, run a health check (SELECT 1) before handing out a connection.

tls_mode: TlsMode

TLS mode for new connections.

tls_ca_cert_pem: Option<Vec<u8>>

Optional custom CA bundle (PEM) for server certificate validation.

mtls: Option<TlsConfig>

Optional mTLS client certificate/key configuration.

gss_token_provider: Option<GssTokenProvider>

Optional callback for Kerberos/GSS/SSPI token generation.

gss_token_provider_ex: Option<GssTokenProviderEx>

Optional stateful callback for Kerberos/GSS/SSPI token generation.

gss_connect_retries: usize

Number of retries for transient GSS/Kerberos connection failures.

gss_retry_base_delay: Duration

Base delay for GSS/Kerberos connect retry backoff.

gss_circuit_breaker_threshold: usize

Transient GSS failures in one window before opening the local circuit.

gss_circuit_breaker_window: Duration

Rolling window used to count transient GSS failures.

gss_circuit_breaker_cooldown: Duration

Cooldown duration while the local GSS circuit stays open.

auth_settings: AuthSettings

Password-auth policy.

gss_enc_mode: GssEncMode

GSSAPI session encryption mode (gssencmode URL parameter).

Implementations

impl PoolConfig

pub fn new(host: &str, port: u16, user: &str, database: &str) -> Self

Create a new pool configuration with production-safe defaults.

Defaults: tls_mode = Require, auth_settings = scram_only(). For local development without TLS, use PoolConfig::new_dev.

Arguments

• host — PostgreSQL server hostname or IP.
• port — TCP port (typically 5432).
• user — PostgreSQL role name.
• database — Target database name.

pub fn new_dev(host: &str, port: u16, user: &str, database: &str) -> Self

Create a pool configuration with permissive defaults for local development.

Defaults: tls_mode = Disable, auth_settings = default() (accepts any auth). Do NOT use in production.

pub fn password(self, password: &str) -> Self

Set password for authentication.

pub fn max_connections(self, max: usize) -> Self

Set maximum simultaneous connections.

pub fn min_connections(self, min: usize) -> Self

Set minimum idle connections.

pub fn idle_timeout(self, timeout: Duration) -> Self

Set idle timeout (connections idle longer than this are closed).

pub fn acquire_timeout(self, timeout: Duration) -> Self

Set acquire timeout (max wait time when getting a connection).

pub fn connect_timeout(self, timeout: Duration) -> Self

Set connect timeout (max time to establish new connection).

pub fn max_lifetime(self, lifetime: Duration) -> Self

Set maximum lifetime of a connection before recycling.

pub fn test_on_acquire(self, enabled: bool) -> Self

Enable connection validation on acquire.

pub fn tls_mode(self, mode: TlsMode) -> Self

Set TLS mode for pool connections.

pub fn tls_ca_cert_pem(self, ca_cert_pem: Vec<u8>) -> Self

Set custom CA bundle (PEM) for TLS validation.

pub fn mtls(self, config: TlsConfig) -> Self

Enable mTLS for pool connections.

pub fn gss_token_provider(self, provider: GssTokenProvider) -> Self

Set Kerberos/GSS/SSPI token provider callback.

pub fn gss_token_provider_ex(self, provider: GssTokenProviderEx) -> Self

Set a stateful Kerberos/GSS/SSPI token provider.

pub fn gss_connect_retries(self, retries: usize) -> Self

Set retry count for transient GSS/Kerberos connection failures.

pub fn gss_retry_base_delay(self, delay: Duration) -> Self

Set base backoff delay for GSS/Kerberos connection retry.

pub fn gss_circuit_breaker_threshold(self, threshold: usize) -> Self

Set failure threshold for opening local GSS circuit breaker.

pub fn gss_circuit_breaker_window(self, window: Duration) -> Self

Set rolling failure window for GSS circuit breaker.

pub fn gss_circuit_breaker_cooldown(self, cooldown: Duration) -> Self

Set cooldown duration for open GSS circuit breaker.

pub fn auth_settings(self, settings: AuthSettings) -> Self

Set authentication policy.

pub fn from_qail_config(qail: &QailConfig) -> PgResult<Self>

Create a PoolConfig from a centralized QailConfig.

Parses postgres.url for host/port/user/database/password and applies pool tuning from [postgres] section.

Trait Implementations

impl Clone for PoolConfig

fn clone(&self) -> PoolConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.