A discovery class that implements a distributed topic discovery protocol. More...

#include <ignition/transport/Discovery.hh>

Public Member Functions
	Discovery (const std::string &_pUuid, const int _port, const bool _verbose=false)
	Constructor. More...

virtual	~Discovery ()
	Destructor. More...

unsigned int	ActivityInterval () const
	The discovery checks the validity of the topic information every 'activity interval' milliseconds. More...

bool	Advertise (const Pub &_publisher)
	Advertise a new message. More...

void	ConnectionsCb (const DiscoveryCallback< Pub > &_cb)
	Register a callback to receive discovery connection events. More...

void	DisconnectionsCb (const DiscoveryCallback< Pub > &_cb)
	Register a callback to receive discovery disconnection events. More...

bool	Discover (const std::string &_topic) const
	Request discovery information about a topic. More...

unsigned int	HeartbeatInterval () const
	Each node broadcasts periodic heartbeats to keep its topic information alive in other nodes. More...

std::string	HostAddr () const
	Get the IP address of this host. More...

const TopicStorage< Pub > &	Info () const
	Get the discovery information. More...

void	PrintCurrentState () const
	Print the current discovery state. More...

bool	Publishers (const std::string &_topic, Addresses_M< Pub > &_publishers) const
	Get all the publishers' information known for a given topic. More...

void	SetActivityInterval (const unsigned int _ms)
	Set the activity interval. More...

void	SetHeartbeatInterval (const unsigned int _ms)
	Set the heartbeat interval. More...

void	SetSilenceInterval (const unsigned int _ms)
	Set the maximum silence interval. More...

unsigned int	SilenceInterval () const
	Get the maximum time allowed without receiving any discovery information from a node before canceling its entries. More...

void	Start ()
	Start the discovery service. More...

void	TopicList (std::vector< std::string > &_topics) const
	Get the list of topics currently advertised in the network. More...

bool	Unadvertise (const std::string &_topic, const std::string &_nUuid)
	Unadvertise a new message. More...

void	WaitForInit () const
	Check if ready/initialized. More...

Protected Attributes
std::map< std::string, Timestamp >	activity
	Activity information. More...

Detailed Description

template<typename Pub>
class ignition::transport::Discovery< Pub >

A discovery class that implements a distributed topic discovery protocol.

It uses UDP broadcast for sending/receiving messages and stores updated topic information. The discovery clients can request the discovery of a topic or the advertisement of a local topic. The discovery uses heartbeats to track the state of other peers in the network. The discovery clients can register callbacks to detect when new topics are discovered or topics are no longer available.

Constructor & Destructor Documentation

template<typename Pub >

ignition::transport::Discovery< Pub >::Discovery	(	const std::string &	_pUuid,
		const int	_port,
		const bool	_verbose = `false`
	)

inline

Constructor.

Parameters

[in]	_pUuid	This discovery instance will run inside a transport process. This parameter is the transport process' UUID.
[in]	_port	UDP port used for discovery traffic.
[in]	_verbose	true for enabling verbose mode.

References ignition::transport::determineInterfaces(), and ignition::transport::env().

template<typename Pub >

virtual ignition::transport::Discovery< Pub >::~Discovery ( )

inlinevirtual

Destructor.

References ignition::transport::ByeType.

Member Function Documentation

template<typename Pub >

unsigned int ignition::transport::Discovery< Pub >::ActivityInterval ( ) const

inline

The discovery checks the validity of the topic information every 'activity interval' milliseconds.

See Also: SetActivityInterval.

Returns: The value in milliseconds.

template<typename Pub >

bool ignition::transport::Discovery< Pub >::Advertise ( const Pub & _publisher )

inline

Advertise a new message.

Parameters

[in] _publisher Publisher's information to advertise.

Returns: True if the method succeed or false otherwise (e.g. if the discovery has not been started).

References ignition::transport::AdvType, and ignition::transport::PROCESS.

template<typename Pub >

void ignition::transport::Discovery< Pub >::ConnectionsCb ( const DiscoveryCallback< Pub > & _cb )

inline

Register a callback to receive discovery connection events.

Each time a new topic is connected, the callback will be executed. This version uses a free function as callback.

Parameters

[in] _cb Function callback.

template<typename Pub >

void ignition::transport::Discovery< Pub >::DisconnectionsCb ( const DiscoveryCallback< Pub > & _cb )

inline

Register a callback to receive discovery disconnection events.

Each time a topic is no longer active, the callback will be executed. This version uses a free function as callback.

Parameters

[in] _cb Function callback.

template<typename Pub >

bool ignition::transport::Discovery< Pub >::Discover ( const std::string & _topic ) const

inline

Request discovery information about a topic.

When using this method, the user might want to use SetConnectionsCb() and SetDisconnectionCb(), that registers callbacks that will be executed when the topic address is discovered or when the node providing the topic is disconnected.

See Also: SetConnectionsCb.; SetDisconnectionsCb.

Parameters

[in] _topic Topic name requested.

Returns: True if the method succeeded or false otherwise (e.g. if the discovery has not been started).

References ignition::transport::SubType.

template<typename Pub >

unsigned int ignition::transport::Discovery< Pub >::HeartbeatInterval ( ) const

inline

Each node broadcasts periodic heartbeats to keep its topic information alive in other nodes.

A heartbeat message is sent after 'heartbeat interval' milliseconds.

See Also: SetHeartbeatInterval.

Returns: The value in milliseconds.

template<typename Pub >

std::string ignition::transport::Discovery< Pub >::HostAddr ( ) const

inline

Get the IP address of this host.

Returns: A string with this host's IP address.

template<typename Pub >

const TopicStorage<Pub>& ignition::transport::Discovery< Pub >::Info ( ) const

inline

Get the discovery information.

Returns: Reference to the discovery information object.

template<typename Pub >

void ignition::transport::Discovery< Pub >::PrintCurrentState ( ) const

inline

Print the current discovery state.

template<typename Pub >

bool ignition::transport::Discovery< Pub >::Publishers	(	const std::string &	_topic,
		Addresses_M< Pub > &	_publishers
	)		const

inline

Get all the publishers' information known for a given topic.

Parameters

[in]	_topic	Topic name.
[out]	_publishers	Publishers requested.

Returns: True if the topic is found and there is at least one publisher

template<typename Pub >

void ignition::transport::Discovery< Pub >::SetActivityInterval ( const unsigned int _ms )

inline

Set the activity interval.

See Also: ActivityInterval.

Parameters

[in] _ms New value in milliseconds.

template<typename Pub >

void ignition::transport::Discovery< Pub >::SetHeartbeatInterval ( const unsigned int _ms )

inline

Set the heartbeat interval.

See Also: HeartbeatInterval.

Parameters

[in] _ms New value in milliseconds.

template<typename Pub >

void ignition::transport::Discovery< Pub >::SetSilenceInterval ( const unsigned int _ms )

inline

Set the maximum silence interval.

See Also: SilenceInterval.

Parameters

[in] _ms New value in milliseconds.

template<typename Pub >

unsigned int ignition::transport::Discovery< Pub >::SilenceInterval ( ) const

inline

Get the maximum time allowed without receiving any discovery information from a node before canceling its entries.

See Also: SetSilenceInterval.

Returns: The value in milliseconds.

template<typename Pub >

void ignition::transport::Discovery< Pub >::Start ( )

inline

Start the discovery service.

You probably want to register the callbacks for receiving discovery notifications before starting the service.

template<typename Pub >

void ignition::transport::Discovery< Pub >::TopicList ( std::vector< std::string > & _topics ) const

inline

Get the list of topics currently advertised in the network.

Parameters

[out] _topics List of advertised topics.

template<typename Pub >

bool ignition::transport::Discovery< Pub >::Unadvertise	(	const std::string &	_topic,
		const std::string &	_nUuid
	)

inline

Unadvertise a new message.

Broadcast a discovery message that will cancel all the discovery information for the topic advertised by a specific node.

Parameters

[in]	_topic	Topic name to be unadvertised.
[in]	_nUuid	Node UUID.

Returns: True if the method succeeded or false otherwise (e.g. if the discovery has not been started).

References ignition::transport::PROCESS, and ignition::transport::UnadvType.

template<typename Pub >

void ignition::transport::Discovery< Pub >::WaitForInit ( ) const

inline

Check if ready/initialized.

If not, then wait on the initializedCv condition variable.

Member Data Documentation

template<typename Pub >

std::map<std::string, Timestamp> ignition::transport::Discovery< Pub >::activity

protected

Activity information.

Every time there is a message from a remote node, its activity information is updated. If we do not hear from a node in a while, its entries in 'info' will be invalided. The key is the process uuid.

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

Discovery.hh

Public Member Functions

Protected Attributes

Detailed Description

template<typename Pub> class ignition::transport::Discovery< Pub >

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename Pub>
class ignition::transport::Discovery< Pub >