MoldUDP64 session manager. More...

Detailed Description

MoldUDP64 session manager.

Manages a complete MoldUDP64 session lifecycle including:

Dual redundant multicast feed reception (A/B feeds)
Automatic failover between feeds
Message sequencing and gap detection
Automatic gap recovery via replay channel
Heartbeat monitoring and link status management
Message caching for local replay

State machine:

InSync: Receiving messages in sequence, no gaps
Recovering: Gap detected, requesting recovery
OutOfSync: Recovery failed or massive gap, manual intervention needed

The session is abstract and requires derived classes to implement:

Message processing (on_message)
Recovery logic (play_snapshot, perform_recovery)
Event handling (on_event)

Note: Thread-safety: Must be used with a single IOContext thread; Derived classes must implement pure virtual methods

See also: Settings; State; Event

#include <nasdaq/moldudp64/Session.h>

Inheritance diagram for b2bits::nasdaq::moldudp64::Session:

Public Types
enum class	State { InSync , Recovering , OutOfSync }
	Session synchronization state. More...
enum class	Source { Realtime , Snapshot , Cache }
	Message source indicator. More...
enum class	Event { LinkUp , LinkDown , EndOfSession , RecoveryStarted , RecoveryStopped , RecoveryFailed , SecdefsAvailable }
	Session lifecycle and recovery events. More...
using	error_code = std::error_code
	Error code type alias.
using	Seqnum = decltype(std::declval<UDPPacket>().get_sn())
	Sequence number type.

Public Member Functions
	Session (std::shared_ptr< b2bits::IOContext > ctx, Settings s, const char *log_pfx=nullptr)
	Construct a MoldUDP64 session.
	~Session ()
	Destructor.
bool	is_started () const
	Check if session is started.
State	get_state () const
	Get current session state.
const std::string &	get_session () const
	Get active MoldUDP64 session name.
std::int64_t	get_msg_recv_time () const
	Get timestamp of last received message.
auto	get_packet_recv_time ()
	Get timestamp of last received packet.
void	start ()
	Start the session.
void	run ()
	Run the session (blocking).
void	stop ()
	Stop the session (synchronous).
template<typename Handler>
void	async_stop (Handler &&h)
	Stop the session asynchronously.
void	pause_udp ()
	Pause UDP multicast reception.
void	resume_udp ()
	Resume UDP multicast reception.
void	operator() (Sequencer &, std::uint64_t sn, std::int64_t timestamp, const MessageBlock *h)
	Handle in-sequence message from sequencer.
void	operator() (Sequencer &, Sequencer::ResetEvent)
	Handle sequencer reset event.
void	operator() (Sequencer &, Sequencer::ReplayEvent)
	Handle sequencer replay event.

Protected Member Functions
std::shared_ptr< b2bits::AsyncSentry >	get_sentry ()
	Get the async operation sentry.
void	set_session (const std::string &s)
	Set the active session name.
void	set_msg_recv_time (std::int64_t val)
	Set the message receive timestamp.
virtual void	on_start_termination ()=0
	Called when session termination begins.
virtual void	on_event (Event e)=0
	Handle session lifecycle events.
virtual void	on_message (Source source, Seqnum sn, const MessageBlock *)=0
	Process a received message.
virtual void	on_eop ()=0
	Called at end of packet processing.
virtual void	on_terminated ()
	Called when session is fully terminated.
virtual void	play_snapshot ()=0
	Play snapshot data during recovery.
virtual void	perform_recovery ()=0
	Perform message recovery.
void	on_recovery_finished (Seqnum next_sn, const error_code &ec)
	Notify recovery completion.

Protected Attributes
const std::string	log_prefix_
	Prefix for log messages.
const Settings	settings_
	Session configuration.
const std::int32_t	id_
	Session identifier.
std::string	active_session_
	Current MoldUDP64 session name.
bool	link_is_up_ = true
	Multicast link status.
std::int64_t	msg_recv_time_ = 0
	Timestamp of last received message.
std::shared_ptr< b2bits::IOContext >	ctx_
	IO context for async operations.

Member Typedef Documentation

◆ error_code

using b2bits::nasdaq::moldudp64::Session::error_code = std::error_code

Error code type alias.

◆ Seqnum

using b2bits::nasdaq::moldudp64::Session::Seqnum = decltype(std::declval<UDPPacket>().get_sn())

Sequence number type.

Member Enumeration Documentation

◆ Event

enum class b2bits::nasdaq::moldudp64::Session::Event

strong

Session lifecycle and recovery events.

Events notified to derived classes for session state changes.

Enumerator
LinkUp	Multicast feed is active (receiving heartbeats).
LinkDown	Multicast feed timeout (no heartbeats).
EndOfSession	End-of-session marker received.
RecoveryStarted	Gap recovery initiated.
RecoveryStopped	Gap recovery completed successfully.
RecoveryFailed	Gap recovery failed, entering OutOfSync state.
SecdefsAvailable	Security definitions are available.

◆ Source

enum class b2bits::nasdaq::moldudp64::Session::Source

strong

Message source indicator.

Identifies where a message originated from during processing.

Enumerator
Realtime	Message from live multicast feed (Feed A or B).
Snapshot	Message from snapshot recovery.
Cache	Message from local message cache.

◆ State

enum class b2bits::nasdaq::moldudp64::Session::State

strong

Session synchronization state.

Indicates the current state of message sequencing and recovery.

Enumerator
InSync	Receiving messages in sequence, no gaps detected.
Recovering	Gap detected, recovery in progress.
OutOfSync	Recovery failed or gap too large, manual intervention needed.

Constructor & Destructor Documentation

◆ Session()

b2bits::nasdaq::moldudp64::Session::Session	(	std::shared_ptr< b2bits::IOContext >	ctx,
		Settings	s,
		const char *	log_pfx = nullptr )

Construct a MoldUDP64 session.

Initializes the session with IO context, settings, and optional log prefix. The session is not started until start() is called.

Parameters

ctx	IO context for async operations
s	Session settings (feeds, timeouts, etc.)
log_pfx	Optional log prefix for identifying this session (default: nullptr)

◆ ~Session()

b2bits::nasdaq::moldudp64::Session::~Session ( )

Destructor.

Ensures proper cleanup and session termination. If the session is still running, it will be stopped.

Member Function Documentation

◆ async_stop()

template<typename Handler>

void b2bits::nasdaq::moldudp64::Session::async_stop ( Handler && h )

inline

Stop the session asynchronously.

Initiates asynchronous session termination. The provided handler is called when termination is complete.

Template Parameters

Handler Handler type (function, lambda, etc.)

Parameters

h	Handler to call on termination completion

◆ get_msg_recv_time()

std::int64_t b2bits::nasdaq::moldudp64::Session::get_msg_recv_time ( ) const

inline

Get timestamp of last received message.

Returns: Message receive timestamp (nanoseconds)

References msg_recv_time_.

◆ get_packet_recv_time()

auto b2bits::nasdaq::moldudp64::Session::get_packet_recv_time ( )

inline

Get timestamp of last received packet.

Returns: Packet receive time point

◆ get_sentry()

std::shared_ptr< b2bits::AsyncSentry > b2bits::nasdaq::moldudp64::Session::get_sentry ( )

inlineprotected

Get the async operation sentry.

Returns: Shared pointer to the sentry guard

◆ get_session()

const std::string & b2bits::nasdaq::moldudp64::Session::get_session ( ) const

inline

Get active MoldUDP64 session name.

Returns: Session identifier string (10 characters)

References active_session_.

◆ get_state()

State b2bits::nasdaq::moldudp64::Session::get_state ( ) const

inline

Get current session state.

Returns: Current State (InSync, Recovering, or OutOfSync)

◆ is_started()

bool b2bits::nasdaq::moldudp64::Session::is_started ( ) const

inline

Check if session is started.

Returns: true if session is active

◆ on_eop()

virtual void b2bits::nasdaq::moldudp64::Session::on_eop ( )

protectedpure virtual

Called at end of packet processing.

Invoked after all messages in a packet have been processed. Useful for batching operations or flushing buffers.

◆ on_event()

virtual void b2bits::nasdaq::moldudp64::Session::on_event ( Event e )

protectedpure virtual

Handle session lifecycle events.

Called when session state changes occur (link up/down, recovery started/stopped, end-of-session, etc.).

Parameters

e	Event type

◆ on_message()

virtual void b2bits::nasdaq::moldudp64::Session::on_message	(	Source	source,
		Seqnum	sn,
		const MessageBlock *	)

protectedpure virtual

Process a received message.

Called for each in-sequence message that needs processing. The message payload follows the MessageBlock header.

Parameters

source	Where the message came from (Realtime/Snapshot/Cache)
sn	Message sequence number
msg	Pointer to MessageBlock header

◆ on_recovery_finished()

void b2bits::nasdaq::moldudp64::Session::on_recovery_finished	(	Seqnum	next_sn,
		const error_code &	ec )

protected

Notify recovery completion.

Derived classes should call this when recovery is complete, providing the next expected sequence number.

Parameters

next_sn	Next expected sequence number after recovery
ec	Error code (success or failure reason)

◆ on_start_termination()

virtual void b2bits::nasdaq::moldudp64::Session::on_start_termination ( )

protectedpure virtual

Called when session termination begins.

Derived classes should perform cleanup and prepare for shutdown. This is called before network connections are closed.

◆ on_terminated()

virtual void b2bits::nasdaq::moldudp64::Session::on_terminated ( )

protectedvirtual

Called when session is fully terminated.

Default implementation does nothing. Override to perform final cleanup after session shutdown.

◆ operator()() [1/3]

void b2bits::nasdaq::moldudp64::Session::operator()	(	Sequencer &	,
		Sequencer::ReplayEvent	)

Handle sequencer replay event.

Called when the sequencer is replaying buffered messages.

Parameters

seq	Sequencer instance
evt	Replay event

◆ operator()() [2/3]

void b2bits::nasdaq::moldudp64::Session::operator()	(	Sequencer &	,
		Sequencer::ResetEvent	)

Handle sequencer reset event.

Called when the sequencer resets (e.g., new session).

Parameters

seq	Sequencer instance
evt	Reset event

◆ operator()() [3/3]

void b2bits::nasdaq::moldudp64::Session::operator()	(	Sequencer &	,
		std::uint64_t	sn,
		std::int64_t	timestamp,
		const MessageBlock *	h )

Handle in-sequence message from sequencer.

Called by the sequencer when a message is ready for processing.

Parameters

seq	Sequencer instance
sn	Sequence number
timestamp	Message timestamp
h	Message block pointer

◆ pause_udp()

void b2bits::nasdaq::moldudp64::Session::pause_udp ( )

Pause UDP multicast reception.

Temporarily stops receiving multicast packets. Useful for throttling or temporary suspension.

◆ perform_recovery()

virtual void b2bits::nasdaq::moldudp64::Session::perform_recovery ( )

protectedpure virtual

Perform message recovery.

Derived classes should implement the recovery logic to request and process missing messages from the replay channel.

◆ play_snapshot()

virtual void b2bits::nasdaq::moldudp64::Session::play_snapshot ( )

protectedpure virtual

Play snapshot data during recovery.

Derived classes should retrieve and process snapshot data to rebuild state during gap recovery.

◆ resume_udp()

void b2bits::nasdaq::moldudp64::Session::resume_udp ( )

Resume UDP multicast reception.

Resumes receiving multicast packets after pause_udp().

◆ run()

void b2bits::nasdaq::moldudp64::Session::run ( )

Run the session (blocking).

Blocks until the session is stopped. This runs the IO context event loop for processing network events.

◆ set_msg_recv_time()

void b2bits::nasdaq::moldudp64::Session::set_msg_recv_time ( std::int64_t val )

inlineprotected

Set the message receive timestamp.

Parameters

val	Timestamp in nanoseconds

References msg_recv_time_.

◆ set_session()

void b2bits::nasdaq::moldudp64::Session::set_session ( const std::string & s )

inlineprotected

Set the active session name.

Parameters

s	Session identifier (10 characters)

References active_session_.

◆ start()

void b2bits::nasdaq::moldudp64::Session::start ( )

Start the session.

Begins receiving multicast data and starts the heartbeat timer. The session enters recovery mode initially to establish sync.

◆ stop()

void b2bits::nasdaq::moldudp64::Session::stop ( )

Stop the session (synchronous).

Stops receiving data and terminates the session synchronously. All resources are cleaned up before returning.

Member Data Documentation

◆ active_session_

std::string b2bits::nasdaq::moldudp64::Session::active_session_

protected

Current MoldUDP64 session name.

Referenced by get_session(), and set_session().

◆ ctx_

std::shared_ptr<b2bits::IOContext> b2bits::nasdaq::moldudp64::Session::ctx_

protected

IO context for async operations.

◆ id_

const std::int32_t b2bits::nasdaq::moldudp64::Session::id_

protected

Session identifier.

◆ link_is_up_

bool b2bits::nasdaq::moldudp64::Session::link_is_up_ = true

protected

Multicast link status.

◆ log_prefix_

const std::string b2bits::nasdaq::moldudp64::Session::log_prefix_

protected

Prefix for log messages.

◆ msg_recv_time_

std::int64_t b2bits::nasdaq::moldudp64::Session::msg_recv_time_ = 0

protected

Timestamp of last received message.

Referenced by get_msg_recv_time(), and set_msg_recv_time().

◆ settings_

const Settings b2bits::nasdaq::moldudp64::Session::settings_

protected

Session configuration.

The documentation for this class was generated from the following file:

nasdaq/moldudp64/Session.h

Detailed Description

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Member Typedef Documentation

◆ error_code

◆ Seqnum

Member Enumeration Documentation

◆ Event

◆ Source

◆ State

Constructor & Destructor Documentation

◆ Session()

◆ ~Session()

Member Function Documentation

◆ async_stop()

◆ get_msg_recv_time()

◆ get_packet_recv_time()

◆ get_sentry()

◆ get_session()

◆ get_state()

◆ is_started()

◆ on_eop()

◆ on_event()

◆ on_message()

◆ on_recovery_finished()

◆ on_start_termination()

◆ on_terminated()

◆ operator()() [1/3]

◆ operator()() [2/3]

◆ operator()() [3/3]

◆ pause_udp()

◆ perform_recovery()

◆ play_snapshot()

◆ resume_udp()

◆ run()

◆ set_msg_recv_time()

◆ set_session()

◆ start()

◆ stop()

Member Data Documentation

◆ active_session_

◆ ctx_

◆ id_

◆ link_is_up_

◆ log_prefix_

◆ msg_recv_time_

◆ settings_