#include <log_service_imp.h>

Static Public Member Functions
static void	init ()
	Initialize a loadable logging service. More...

static void	exit ()
	De-initialize a loadable logging service. More...

static int	run (void instance, log_line ll) noexcept
	Have the service process one log line. More...

static log_service_error	flush (void **instance) noexcept
	Flush any buffers. More...

static log_service_error	open (log_line ll, void *instance) noexcept
	Open a new instance. More...

static log_service_error	close (void **instance) noexcept
	Close and release an instance. More...

static int	characteristics (void) noexcept
	Get characteristics of a log-service. More...

static log_service_error	parse_log_line (const char *line_start, size_t line_length) noexcept
	Parse a single line in an error log of this format. More...

static log_service_error	get_log_name (void instance, char buf, size_t bufsize) noexcept
	Provide the name for a log file this service would access. More...

Member Function Documentation

◆ characteristics()

int log_service_imp::characteristics ( void )

staticnoexcept

Get characteristics of a log-service.

Returns: <0 an error occurred; >=0 characteristics (a set of log_service_chistics flags)

Return values

<0	an error occurred
>=0	characteristics (a set of log_service_chistics flags)

◆ close()

log_service_error log_service_imp::close ( void ** instance )

staticnoexcept

Close and release an instance.

Flushes any buffers.

Returns: <0 an error occurred; =0 success

Flushes any buffers.

Parameters

instance State-pointer that was returned on open. If memory was allocated for this state, it should be released, and the pointer set to nullptr.

Returns: LOG_SERVICE_SUCCESS Success; otherwise An error occurred

Flushes any buffers.

Return values

<0	an error occurred
=0	success

Flushes any buffers.

Returns: LOG_SERVICE_SUCCESS

Flushes any buffers.

Return values

LOG_SERVICE_SUCCESS	success
otherwise	an error occurred

◆ exit()

static void log_service_imp::exit ( )

static

De-initialize a loadable logging service.

◆ flush()

log_service_error log_service_imp::flush ( void ** instance )

staticnoexcept

Flush any buffers.

This function will be called by the server on FLUSH ERROR LOGS. The service may write its buffers, close and re-open any log files to work with log-rotation, etc. The flush function MUST NOT itself log anything (as the caller holds THR_LOCK_log_stack)! A service implementation may provide a nullptr if it does not wish to provide a flush function.

Returns: <0 an error occurred; =0 no work was done; >0 flush completed without incident

This function will be called by the server on FLUSH ERROR LOGS. The service may write its buffers, close and re-open any log files to work with log-rotation, etc. The flush function MUST NOT itself log anything! A service implementation may provide a nullptr if it does not wish to provide a flush function.

Parameters

instance State-pointer that was returned on open. Value may be changed in flush.

Returns: LOG_SERVICE_NOTHING_DONE no work was done

This function will be called by the server on FLUSH ERROR LOGS. The service may write its buffers, close and re-open any log files to work with log-rotation, etc. The flush function MUST NOT itself log anything (as the caller holds THR_LOCK_log_stack)! A service implementation may provide a nullptr if it does not wish to provide a flush function.

Return values

LOG_SERVICE_NOTHING_DONE	no work was done
LOG_SERVICE_SUCCESS	flush completed without incident
otherwise	an error occurred

◆ get_log_name()

log_service_error log_service_imp::get_log_name	(	void *	instance,
		char *	buf,
		size_t	bufsize
	)

staticnoexcept

Provide the name for a log file this service would access.

Parameters

instance	instance info returned by open() if requesting the file-name for a specific open instance. nullptr to get the name of the default instance (even if it that log is not open). This is used to determine the name of the log-file to load on start-up.
buf	Address of a buffer allocated in the caller. The callee may return an extension starting with '.', in which case the path and file-name will be the system's default, except with the given extension. Alternatively, the callee may return a file-name which is assumed to be in the same directory as the default log. Values are C-strings.
bufsize	The size of the allocation in the caller.

Return values

0	Success
-1	Mode not supported (only default / only instances supported)
-2	Buffer not large enough
-3	Misc. error

◆ init()

static void log_service_imp::init ( )

static

Initialize a loadable logging service.

◆ open()

log_service_error log_service_imp::open	(	log_line *	ll,
		void **	instance
	)

staticnoexcept

Open a new instance.

Returns: <0 a new instance could not be created; =0 success, returned handle is valid

Parameters

ll Optional arguments

instance If state is needed, the service may allocate and initialize it and return a pointer to it here. (This of course is particularly pertinent to components that may be opened multiple times, such as the JSON log writer.) This state is for use of the log-service component in question only and can take any layout suitable to that component's need. The state is opaque to the server/logging framework. It must be released on close.

Returns: LOG_SERVICE_SUCCESS Success, returned handle is valid; otherwise A new instance could not be created

Return values

<0	a new instance could not be created
=0	success, returned handle is valid

Returns: LOG_SERVICE_SUCCESS success, returned handle is valid; otherwise a new instance could not be created

Return values

LOG_SERVICE_SUCCESS	success, returned handle is valid
otherwise	a new instance could not be created

◆ parse_log_line()

log_service_error log_service_imp::parse_log_line	(	const char *	line_start,
		size_t	line_length
	)

staticnoexcept

Parse a single line in an error log of this format.

(optional)

Returns: 0 Success; !=0 Failure (out of memory, malformed argument, etc.)

Parameters

line_start	pointer to the beginning of the line ('{')
line_length	length of the line

Return values

0	Success
!=0	Failure (out of memory, malformed argument, etc.)

◆ run()

int log_service_imp::run	(	void *	instance,
		log_line *	ll
	)

staticnoexcept

Have the service process one log line.

services: log sinks: basic structured dump writer

services: log sinks: classic syslog/EventLog writer (message only) label will be ignored (one will be generated from priority by the syslogger).

services: log sinks: JSON structured dump writer Will write structured info to stderr/file.

services: log filter: basic filtering

If a run function wishes to itself use error logging in case of severe failure, it may do so after FIRST securing the all further calls to run() will be rejected. "log_sink_test" implements an example of this.

The actual dragnet filtering engine is currently the default filter and therefore built-in (see components/mysql_server/log_builtins_filter.cc); this service is just a configuration language parser/compiler/decompiler; once it has set up the filter rule-set according to the user's instructions, it calls on the built-in engine to do the actual filtering.

Third parties could in theory write their own filtering language on top of that engine; they could also create their own filtering engine and use it instead of the provided one.

Parameters

ll	The log line to filter
instance	Instance (unused in dragnet as it's not currently multi-open; we just always use log_filter_dragnet_rules)

Returns: int Number of matched rules

Binary will be escaped according to JSON rules. If you should not be able to specify a label, one will be generated for you from the line's priority field.

Returns: >=0 Number of accepted fields, if any; <0 c Error

If the message is not \0 terminated, it will be terminated.

Returns: >=0 number of accepted fields, if any; LOG_SERVICE_NOT_AVAILABLE log was not open; LOG_SERVICE_INVALID_ARGUMENT could not sanitize log message; LOG_SERVICE_MISC_ERROR failure not otherwise specified

This is intended for testing and debugging, not production.

Writes all fields. No escaping is done. Submits various events of its own to demonstrate the availability of the error event submission interface from within external service, as well as the correct functioning of said interface.

Returns: int number of accepted fields, if any; <0 failure

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

components/logging/log_service_imp.h
components/logging/log_filter_dragnet.cc
components/logging/log_sink_json.cc
components/logging/log_sink_syseventlog.cc
components/logging/log_sink_test.cc

Static Public Member Functions

Member Function Documentation

◆ characteristics()

◆ close()

◆ exit()

◆ flush()

◆ get_log_name()

◆ init()

◆ open()

◆ parse_log_line()

◆ run()