Interface EventStore

mcp/event.go:164–192

An EventStore tracks data for SSE streams. A single EventStore suffices for all sessions, since session IDs are globally unique. So one EventStore can be created per process, for all Servers in the process. Such a store is able to bound resource usage for the entire process. All of an EventStore's

//
// All of an EventStore's methods must be safe for use by multiple goroutines.
type EventStore interface {
	// Open is called when a new stream is created. It may be used to ensure that
	// the underlying data structure for the stream is initialized, making it
	// ready to store and replay event streams.
	Open(_ context.Context, sessionID, streamID string) error

	// Append appends data for an outgoing event to given stream, which is part of the
	// given session.
	Append(_ context.Context, sessionID, streamID string, data []byte) error

	// After returns an iterator over the data for the given session and stream, beginning
	// just after the given index.
	//
	// Once the iterator yields a non-nil error, it will stop.
	// After's iterator must return an error immediately if any data after index was
	// dropped; it must not return partial results.
	// The stream must have been opened previously (see [EventStore.Open]).
	After(_ context.Context, sessionID, streamID string, index int) iter.Seq2[[]byte, error]

	// SessionClosed informs the store that the given session is finished, along
	// with all of its streams.
	//
	// A store cannot rely on this method being called for cleanup. It should institute
	// additional mechanisms, such as timeouts, to reclaim storage.
	SessionClosed(_ context.Context, sessionID string) error

	// There is no StreamClosed method. A server doesn't know when a stream is finished, because
	// the client can always send a GET with a Last-Event-ID referring to the stream.
}

// A dataList is a list of []byte.
// The zero dataList is ready to use.