mysql_harness::DynamicState Class Reference

DynamicState represents a MySQLRouter dynamic state object. More...

#include <dynamic_state.h>

Classes
struct	Pimpl

Public Member Functions
	DynamicState (const std::string &file_name)
	Creates and initializes dynamic state object. More...
	~DynamicState ()
	Destructor. More...
bool	load ()
	Loads the json state object from the associated file, overwrites the current with the file content. More...
bool	save (bool is_clusterset, bool pretty=true)
	Saves the json state object to the associated file, overwrites the the file content. More...
bool	save_to_stream (std::ostream &output_stream, bool is_clusterset, bool pretty=true)
	Saves the json state object to the output stream given as a parameter, overwrites the stream content. More...
std::unique_ptr< JsonValue >	get_section (const std::string &section_name)
	Returns selected state object section by its name. More...
bool	update_section (const std::string &section_name, JsonValue &&value)
	Updates selected state object section. More...

Private Member Functions
bool	load_from_stream (std::istream &input_stream)
void	ensure_valid_against_schema ()
void	ensure_version_compatibility ()
std::ifstream	open_for_read ()
std::ofstream	open_for_write ()

Private Attributes
std::unique_ptr< Pimpl >	pimpl_
std::string	file_name_
std::string	tmp_file_name_

Detailed Description

DynamicState represents a MySQLRouter dynamic state object.

It's meant to be used as a singleton that provides methods to read/update sections from the specific modules requiring saving their runtime state.

It handles the file handling synchronization, versioning and validation.

Constructor & Destructor Documentation

DynamicState()

mysql_harness::DynamicState::DynamicState

(

const std::string &

file_name

)

Creates and initializes dynamic state object.

Parameters

file_name

path to the json file where the state is being stored

~DynamicState()

mysql_harness::DynamicState::~DynamicState ( )

default

Destructor.

Member Function Documentation

ensure_valid_against_schema()

void mysql_harness::DynamicState::ensure_valid_against_schema ( )

private

ensure_version_compatibility()

void mysql_harness::DynamicState::ensure_version_compatibility ( )

private

get_section()

std::unique_ptr< JsonValue > mysql_harness::DynamicState::get_section

(

const std::string &

section_name

)

Returns selected state object section by its name.

Parameters

section_name

name of the section to retrieve

Returns

pointer to the rapidJson object containing the section, nullptr if the section with a given name does not exist

load()

bool mysql_harness::DynamicState::load

(

)

Loads the json state object from the associated file, overwrites the current with the file content.

Returns

success of operation

Return values

true	operation succeeded
false	operation failed

load_from_stream()

bool mysql_harness::DynamicState::load_from_stream ( std::istream &  input_stream )

private

open_for_read()

std::ifstream mysql_harness::DynamicState::open_for_read ( )

private

open_for_write()

std::ofstream mysql_harness::DynamicState::open_for_write ( )

private

save()

bool mysql_harness::DynamicState::save	(	bool	is_clusterset,
		bool	pretty = true
	)

Saves the json state object to the associated file, overwrites the the file content.

Parameters

is_clusterset	true if the metadata is configured to work with a ClusterSet, false if a single Cluster
pretty	if true the json data is written in a human readable json format

Returns

success of operation

Return values

true	operation succeeded
false	operation failed

save_to_stream()

bool mysql_harness::DynamicState::save_to_stream	(	std::ostream &	output_stream,
		bool	is_clusterset,
		bool	pretty = true
	)

Saves the json state object to the output stream given as a parameter, overwrites the stream content.

Parameters

output_stream	stream where json content should be written to
is_clusterset	true if the metadata is configured to work with a ClusterSet, false if a single Cluster
pretty	if true the json data is written in a human readable json format

Returns

success of operation

Return values

true	operation succeeded
false	operation failed

update_section()

bool mysql_harness::DynamicState::update_section	(	const std::string &	section_name,
		JsonValue &&	value
	)

Updates selected state object section.

Parameters

section_name	name of the section to update
value	rapidJson object to replaces the section value

Returns

success of operation

Return values

true	operation succeeded
false	operation failed

Member Data Documentation

file_name_

std::string mysql_harness::DynamicState::file_name_

private

pimpl_

std::unique_ptr<Pimpl> mysql_harness::DynamicState::pimpl_

private

tmp_file_name_

std::string mysql_harness::DynamicState::tmp_file_name_

private

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

• router/src/harness/include/mysql/harness/dynamic_state.h
• router/src/harness/src/dynamic_state.cc