Maps a set of proxy names to their associated IP addresses. More...

#include <ProxyMap.h>

Collaboration diagram for Hypertable::ProxyMap:

Public Member Functions
void	update_mapping (const String &proxy, const String &hostname, const InetAddr &addr, ProxyMapT &invalidated_map, ProxyMapT &new_map)
	Updates a proxy name mapping. More...

void	update_mappings (String &mappings, ProxyMapT &invalidated_map, ProxyMapT &new_map)
	Update mappings from proxy map update message string. More...

void	remove_mapping (const String &proxy, ProxyMapT &remove_map)
	Removes a mapping. More...

bool	get_mapping (const String &proxy, String &hostname, InetAddr &addr)
	Returns proxy map data for `proxy`. More...

String	get_proxy (InetAddr &addr)
	Returns proxy name for `addr`. More...

void	get_map (ProxyMapT &map)
	Returns the forward map (proxy name to ProxyAddressInfo) More...

CommBufPtr	create_update_message ()
	Creates a proxy map update message. More...

String	to_str ()

Private Member Functions
void	invalidate_old_mapping (const String &proxy, const InetAddr &addr, ProxyMapT &invalidated_mappings)
	Invalidates (removes) mapping, if changed, from forward and reverse maps. More...

void	invalidate (const String &proxy, ProxyMapT &invalidated_mappings)
	Invalidates (removes) mapping from forward and reverse maps. More...

Private Attributes
std::mutex	m_mutex
	Mutex for serializing concurrent access More...

ProxyMapT	m_forward_map
	Forward map from proxy name to ProxyAddressInfo. More...

SockAddrMap< String >	m_reverse_map
	Reverse map from IP address to proxy name. More...

Detailed Description

Maps a set of proxy names to their associated IP addresses.

Hypertable uses proxy names (e.g. "rs1") to refer to servers so that the system can continue to operate properly even when servers are reassigned IP addresses, such as starting and stopping Hypertable running on EBS volumes in AWS EC2. There is a single ProxyMap associated with each Comm layer and one of the connected participants is designated as the proxy master by setting the global variable ReactorFactory::proxy_master to true. In Hypertable, the Master is designated as the proxy master. The proxy master is responsible for assigning proxy names which are just mnemonic strings (e.g. "rs1"). Whenever a server connects to the proxy master, the proxy master will either assign the newly connected server a proxy name or obtain it via a handshake and should then update the proxy map with the {proxy name, IP address} association and will propagate the new proxy map information to all connected participants. Once this is complete, all connected participants and send and receive messages to any participant using its proxy name. The CommAddress class is an abstraction that can hold either a proxy name or an IP address and used to identify the destination of a message.

Definition at line 79 of file ProxyMap.h.

Member Function Documentation

CommBufPtr ProxyMap::create_update_message ( )

Creates a proxy map update message.

This method is called by the proxy master to create a proxy map update message to be sent to all connected processes. The proxy map update message consists of a list of proxy mappings in the following format:

<proxy> '\t' <hostname> '\t' <addr> '\n'

The forward map is traversed to generate the list of mappings which are added to a newly allocated CommBuf object. The CommBuf object is initialized with a CommHeader that has the CommHeader::FLAGS_BIT_PROXY_MAP_UPDATE bit set in its flags member.

Returns: CommBuf object holding the proxy map update message (to be freed by caller).

Definition at line 127 of file ProxyMap.cc.

void Hypertable::ProxyMap::get_map ( ProxyMapT & map )

inline

Returns the forward map (proxy name to ProxyAddressInfo)

Parameters

map	Reference to return forward map

Definition at line 164 of file ProxyMap.h.

bool ProxyMap::get_mapping	(	const String &	proxy,
		String &	hostname,
		InetAddr &	addr
	)

Returns proxy map data for proxy.

This method looks up proxy in the forward map and returns the associated hostname and address information, if found.

Parameters

proxy	Proxy name for which to fetch mapping information
hostname	Reference to returned hostname
addr	Reference to returned address

Returns: true if mapping found, false otherwise.

Definition at line 108 of file ProxyMap.cc.

String ProxyMap::get_proxy ( InetAddr & addr )

Returns proxy name for addr.

This method looks up addr in the reverse map and returns the proxy name, if found.

Parameters

addr	Address for which to fetch proxy name

Returns: Proxy name of addr if found in reverse map, otherwise the empty string.

Definition at line 118 of file ProxyMap.cc.

void ProxyMap::invalidate	(	const String &	proxy,
		ProxyMapT &	invalidated_mappings
	)

private

Invalidates (removes) mapping from forward and reverse maps.

This method looks up proxy in the forward map and removes it, if it exists. If mapping found in forward map, the corresponding mapping is also removed from the reverse map. The removed mapping is added to invalidated_mappings with the hostname set to "--DELETED--".

Parameters

proxy	Proxy name to invalidate
invalidated_mappings	Reference to ProxyMapT object to hold invalidated mapping.

Definition at line 167 of file ProxyMap.cc.

void ProxyMap::invalidate_old_mapping	(	const String &	proxy,
		const InetAddr &	addr,
		ProxyMapT &	invalidated_mappings
	)

private

Invalidates (removes) mapping, if changed, from forward and reverse maps.

This method looks up proxy in the forward map and removes it if it exists but maps to an address different from addr. It also looks up addr in the reverse map and removes it if it exists and it maps to a proxy different than proxy. The removed mappings are added to invalidated_mappings.

Parameters

proxy	Proxy name to invalidate
addr	IP address to invalidate
invalidated_mappings	Reference to ProxyMapT object to hold invalidated mappings.

Definition at line 142 of file ProxyMap.cc.

void ProxyMap::remove_mapping	(	const String &	proxy,
		ProxyMapT &	remove_map
	)

Removes a mapping.

This method removes the mapping for proxy and adds the removed mapping to remove_map with the hostname set to –DELETED– (see update_mappings). The proxy master calls this method to remove a mapping and then propagates remove_map to all connections.

Parameters

proxy	Proxy for which mapping is to be removed
remove_map	Reference to return map to hold removed mappings

Definition at line 100 of file ProxyMap.cc.

String ProxyMap::to_str ( )

Definition at line 189 of file ProxyMap.cc.

void ProxyMap::update_mapping	(	const String &	proxy,
		const String &	hostname,
		const InetAddr &	addr,
		ProxyMapT &	invalidated_map,
		ProxyMapT &	new_map
	)

Updates a proxy name mapping.

This method first checks to see if there is already a mapping from proxy to addr in the forawrd map. If so, then it updates the hostname. Otherwise, it invalidates proxy from the forward map and addr from the reverse map and adds entries to the forward and reverse maps for the new mapping. Any invalidated mappings are added to invalidated_map and the new forward mapping from proxy to ProxyAddressInfo is added to new_map.

Parameters

proxy	Proxy name of new/updated mapping
hostname	Hostname of new/updated mapping
addr	InetAddr of new/updated mapping
invalidated_map	Reference to return map to hold invalidated mappings
new_map	Reference to return map to hold new forward mapping

Definition at line 38 of file ProxyMap.cc.

void ProxyMap::update_mappings	(	String &	mappings,
		ProxyMapT &	invalidated_map,
		ProxyMapT &	new_map
	)

Update mappings from proxy map update message string.

One process in the system is designated as the proxy master and is responsible for updating the proxy mappings for all connected processes. This method is called by connected processes to update their proxy maps from a proxy map update message received by the proxy master. The proxy map update message consists of a list of mappings in the following format:

<proxy> '\t' <hostname> '\t' <addr> '\n'

For each mapping in mappings this method first checks to see if there is already a mapping from proxy to addr in the forawrd map. If so, then it updates the hostname. Otherwise, it invalidates proxy from the forward map and addr from the reverse map and adds entries to the forward and reverse maps for the new mapping. Any invalidated mappings are added to invalidated_map and the new forward mapping from proxy to ProxyAddressInfo is added to new_map. A hostname entry of –DELETED– means that the entry is to be removed. In this situation, this method invalidates proxy from the forward map and addr from the reverse map and the invalidated mappings are added to invalidated_map.

Parameters

mappings	Proxy map update message string
invalidated_map	Reference to return map to hold invalidated mappings
new_map	Reference to return map to hold new forward mapping

Definition at line 55 of file ProxyMap.cc.

Member Data Documentation

ProxyMapT Hypertable::ProxyMap::m_forward_map

private

Forward map from proxy name to ProxyAddressInfo.

Definition at line 217 of file ProxyMap.h.

std::mutex Hypertable::ProxyMap::m_mutex

private

Mutex for serializing concurrent access

Definition at line 214 of file ProxyMap.h.

SockAddrMap<String> Hypertable::ProxyMap::m_reverse_map

private

Reverse map from IP address to proxy name.

Definition at line 220 of file ProxyMap.h.

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

/home/doug/src/hypertable/src/cc/AsyncComm/ProxyMap.h
/home/doug/src/hypertable/src/cc/AsyncComm/ProxyMap.cc

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation