Struct CommandGate 

pub struct CommandGate { /* private fields */ }

Decides whether a trading command may go out now.

A connector asks the gate before it sends a place, cancel or replace. The gate refuses in three cases, checked in this order: the connector is shutting down, it is degraded, it has not been reconciled yet. The gate starts closed (not reconciled), so the first reconcile with the broker opens it. Why: before the client knows which orders already exist at the broker, a new command could duplicate or fight an order it cannot see.

The gate only holds flags. The connector sets them: mark_reconciled after a successful reconcile, mark_degraded when the Emitter reports an overflow, begin_shutdown when closing. Reads (order book, portfolio, active orders) are not gated.

Examples

use brokapi_core::Error;
use brokapi_runtime::CommandGate;

let mut gate = CommandGate::new();
// A new gate refuses commands until the first reconcile.
assert!(matches!(gate.check_command(), Err(Error::NotReconciled)));

gate.mark_reconciled();
assert!(gate.check_command().is_ok());

// An overflow of a lossless stream closes it again until the next reconcile.
gate.mark_degraded();
assert!(matches!(gate.check_command(), Err(Error::Degraded)));
gate.clear_degraded();
assert!(gate.check_command().is_ok());

// Shutdown wins over everything else and is final.
gate.begin_shutdown();
assert!(matches!(gate.check_command(), Err(Error::ShuttingDown)));

Implementations

impl CommandGate

pub fn new() -> Self

Creates a closed gate. Same as Default::default.

pub fn is_reconciled(&self) -> bool

Whether mark_reconciled was called.

pub fn is_degraded(&self) -> bool

Whether the gate is in the degraded state.

pub fn mark_reconciled(&mut self)

Records a successful reconcile. There is no way to undo it.

pub fn mark_degraded(&mut self)

Records that events were lost (see Emitter::is_degraded). Commands are refused until clear_degraded.

pub fn clear_degraded(&mut self)

Leaves the degraded state. Call it after the reconcile that made up for the lost events.

pub fn begin_shutdown(&mut self)

Closes the gate for good: every later check fails with [Error::ShuttingDown].

pub fn check_command(&self) -> Result<(), Error>

Says whether a trading command may be sent now.

Errors

In this order of priority:

• [Error::ShuttingDown] after begin_shutdown.
• [Error::Degraded] while the gate is degraded.
• [Error::NotReconciled] until mark_reconciled.

All three mean nothing was sent, so the command may be repeated once the cause is gone (except after a shutdown).

Trait Implementations

impl Clone for CommandGate

fn clone(&self) -> CommandGate

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CommandGate

impl Debug for CommandGate

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

Formats the value using the given formatter.

impl Default for CommandGate

fn default() -> Self

A closed gate: not reconciled, not degraded, not shutting down.

impl Eq for CommandGate

impl PartialEq for CommandGate

fn eq(&self, other: &CommandGate) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for CommandGate