Struct InMemoryEventLog 

pub struct InMemoryEventLog { /* private fields */ }

A task’s update log held in this process’s memory.

Cloning shares the log, so a clone sees the same events. This is the default under InMemoryStreamingHandler, and it is what makes resumption work within one run of a server: a client that reconnects gets the tail it missed, up to capacity events per task.

What it cannot do is survive the process. A restart starts every task’s ids again at 1, and a client resuming with an id from before the restart is told the log cannot cover it (Replay::complete is false) rather than handed a tail that means something else. Use a durable log — SqlxTaskStorage implements this port — where resumption has to outlive a restart.

Retained tasks are never evicted: a task that has finished still holds its ring until discard is called for it. Bounded per task, unbounded in task count, which is the other reason a long-running server wants the durable log.

Implementations

impl InMemoryEventLog

pub fn new() -> Self

A log keeping DEFAULT_CAPACITY events per task.

pub fn with_capacity(capacity: usize) -> Self

A log keeping capacity events per task.

A capacity of zero would retain nothing and make every resume incomplete, so it is raised to one.

Trait Implementations

impl AsyncEventLog for InMemoryEventLog

fn append<'life0, 'life1, 'async_trait>( &'life0 self, task_id: &'life1 str, event: UpdateEvent, ) -> Pin<Box<dyn Future<Output = Result<SeqEvent, A2AError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Record event as the next event on task_id’s stream and return it with the id it was given.

fn replay<'life0, 'life1, 'async_trait>( &'life0 self, task_id: &'life1 str, from: u64, ) -> Pin<Box<dyn Future<Output = Result<Replay, A2AError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

What this log can still replay to a client whose last id was from.

fn discard<'life0, 'life1, 'async_trait>( &'life0 self, task_id: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<(), A2AError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Forget a task’s events.

impl Clone for InMemoryEventLog

fn clone(&self) -> InMemoryEventLog

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for InMemoryEventLog

fn default() -> Self

Returns the “default value” for a type.