Classes
struct	CompareConnections

class	ConnectionState

class	ConnectionStateManager

struct	FlagState

struct	FlagContext

class	FlagConfig

class	Flag

class	FlagConfigManager

class	FlagUveManager

class	FlagManager

class	Signal

Typedefs
typedef boost::asio::ip::tcp::endpoint	Endpoint

typedef boost::function< void(const std::vector< ConnectionInfo > &, ProcessState::type &, std::string &)>	ProcessStateFn

typedef std::pair< std::string, std::string >	ConnectionTypeName

typedef std::vector< FlagContext >	ContextVec

typedef std::vector < FlagContext > ::const_iterator	context_iterator

typedef std::vector < FlagContext >::size_type	context_size

typedef std::vector< FlagConfig >	FlagConfigVec

typedef std::vector < FlagConfig >::const_iterator	flag_cfg_itr

typedef std::vector< Flag >	FlagVec

Functions
void	GetProcessStateCb (const vector< ConnectionInfo > &cinfos, ProcessState::type &state, string &message, const vector< ConnectionTypeName > &expected_connections)

void	GetConnectionInfoMessage (const vector< ConnectionInfo > &cinfos, const vector< ConnectionTypeName > &expected_connections, string &message)

void	GetProcessStateCb (const std::vector< ConnectionInfo > &cinfos, ProcessState::type &state, std::string &message, const std::vector< ConnectionTypeName > &expected_connections)

void	GetConnectionInfoMessage (const std::vector< ConnectionInfo > &cinfos, const std::vector< ConnectionTypeName > &expected_connections, std::string &message)

Variables
bool	debug_ = true

Detailed Description

C++ feature flag interface for developers

The Flag class serves as the interface for modules interested in one or more feature flags.

Developers bringing in new features can declare a flag in global scope. Construction requires specifying a name, description of the flag, and a default value.

Flag flag_enable_hash_v2("Hash V2", "Enable the use of
                          the new generation hash table", false);

A flag can be declared as belonging to the instance of an object. This means that it can have a different definition per object.

class Module {
  public:
    Module(const std::string interface_name, const Options& options);
  private:
    Flag enable_hash_v2_;
    HashTable* ht_;
};

When a module is instantiated, the internal flag is initialized. The initialization uses the global flag definition and can be personalized. The second parameter is a key-value dict that provides the context info and the third parameter is a callback that will be invoked if there are configuration or run-time updates to the feature flag definition.

Module::Module(const std::string name, const Options& options)
    : enable_hash_v2_(flag_enable_hash_v2,
                      {"interface", interface_name},
                      flag_update_cb) {
    if (enable_hash_v2_.Get()) {
        ht_ = NewFancyHashTable();
    } else {
        ht_ = OldHashTable();
    }
}

The FlagConfig class serves as an interface for storing user configuration for features. User configuration for feature flag is provided to the FlagManager using this class. Used by servers providing config data (ifmap_server) Data provided includes

Flag name
bool indicating if flag is enabled
bool indicating default value
Release in which the flag was introduced
Context Info (optional)

The FlagManager class is a flag store that maintains the list of feature flags modules are interested in and the user configuration for them if any. When the Flag class is instantiated, it automatically registers itself with the flag store. When the FlagConfig class is instantiated, it informs the flag store of the user configuration for flags. The FlagManager class on receiving the user configuration for a flag will update the flag and sets the "enabled" field in accordance with the user configuration. In addition, it will invoke any callbacks registered by modules.

A FlagUveManager class is responsible for providing functionality to interface with analytics/introspect to provide data on the feature flags configured in each module. Analytics registers callbacks using this class which will

be called when there is a change to flag definition or configuration.

Typedef Documentation

typedef std::pair<std::string, std::string> process::ConnectionTypeName

Definition at line 35 of file connection_info.h.

typedef std::vector<FlagContext>::const_iterator process::context_iterator

Definition at line 182 of file feature_flags.h.

typedef std::vector<FlagContext>::size_type process::context_size

Definition at line 183 of file feature_flags.h.

typedef std::vector<FlagContext> process::ContextVec

Definition at line 181 of file feature_flags.h.

typedef boost::asio::ip::tcp::endpoint process::Endpoint

Definition at line 31 of file connection_info.h.

typedef std::vector<FlagConfig>::const_iterator process::flag_cfg_itr

Definition at line 240 of file feature_flags.h.

typedef std::vector<FlagConfig> process::FlagConfigVec

Definition at line 239 of file feature_flags.h.

typedef std::vector<Flag> process::FlagVec

Definition at line 324 of file feature_flags.h.

typedef boost::function<void (const std::vector<ConnectionInfo> &, ProcessState::type &, std::string &)> process::ProcessStateFn

Definition at line 33 of file connection_info.h.

Function Documentation

void process::GetConnectionInfoMessage	(	const std::vector< ConnectionInfo > &	cinfos,
		const std::vector< ConnectionTypeName > &	expected_connections,
		std::string &	message
	)

void process::GetConnectionInfoMessage	(	const vector< ConnectionInfo > &	cinfos,
		const vector< ConnectionTypeName > &	expected_connections,
		string &	message
	)

Definition at line 193 of file connection_info.cc.

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void process::GetProcessStateCb	(	const std::vector< ConnectionInfo > &	cinfos,
		ProcessState::type &	state,
		std::string &	message,
		const std::vector< ConnectionTypeName > &	expected_connections
	)

void process::GetProcessStateCb	(	const vector< ConnectionInfo > &	cinfos,
		ProcessState::type &	state,
		string &	message,
		const vector< ConnectionTypeName > &	expected_connections
	)

Definition at line 135 of file connection_info.cc.

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Variable Documentation

bool process::debug_ = true

Definition at line 18 of file feature_flags.cc.

Classes

Typedefs