components::Logging Class Reference

#include <userver/logging/component.hpp>

Detailed Description

Logging component

Allows to configure the default logger and/or additional loggers for your needs.

Static options of components::Logging :

Options inherited from components::RawComponentBase :

default logger is the one used for LOG_*.

Logs output

You can specify where logs are written in the file_path option:

• Use file_path: '@stdout' to write your logs to standard output stream;
• Use file_path: '@stderr' to write your logs to standard error stream;
• Use file_path: '@null' to suppress sending of logs;
• Use file_path: /absolute/path/to/log/file.log to write your logs to file. Use USR1 signal or server::handlers::OnLogRotate to reopen files after log rotation;
• Use file_path: 'unix:/absolute/path/to/logs.sock' to write your logs to unix socket. Socket must be created before the service starts and closed by listener after service is shut down.

For sending logs directly to an otlp (opentelemetry) sink, see opentelemetry.

Customization of log sinks beyond the ones listed above is not supported at the moment.

Logs format

You can specify in what format logs are written in the format option:

• Use format: tskv for traditional optimized userver-flavoured TSKV representation. See utils::encoding::TskvParser for the exact format specification;
• Use format: ltsv for the same format, with : instead of = for key-value separator;
• Use format: raw for TSKV logs with timestamp and other default tags stripped, useful for custom loggers;
• Use format: json for JSON logs. logging::JsonString can be used with this format for rich hierarchical log tags;
• Use format: json_yadeploy for JSON logs with a slightly different structure.

When sending logs using opentelemetry, logs are written to otlp protobuf messages.

Customization of log formats beyond the ones listed above is not supported at the moment.

Static configuration examples:

Writing logs to stderr:

        logging:
            fs-task-processor: fs-task-processor
            loggers:
                default:
                    file_path: '@stderr'
                    level: info

Advanced configuration showing options for access logs and a custom opentracing logger:

# yaml
    logging:
      fs-task-processor: fs-task-processor
      loggers:
        default:
          file_path: $default_log_path
          level: $log_level
          level#fallback: debug
          overflow_behavior: discard
        access:
          file_path: $access_log_path
          overflow_behavior: discard
          format: raw
        access-tskv:
          file_path: $access_tskv_log_path
          overflow_behavior: discard
          format: raw
        tracer:
          file_path: '@stdout'
          overflow_behavior: discard

Definition at line 83 of file component.hpp.

Inheritance diagram for components::Logging:

Public Member Functions
	Logging (const ComponentConfig &, const ComponentContext &)
	The component constructor.
logging::LoggerPtr	GetLogger (const std::string &name)
	Returns a logger by its name.
logging::TextLoggerPtr	GetTextLogger (const std::string &name)
	Returns a text logger by its name.
void	SetLogger (const std::string &name, logging::LoggerPtr logger)
	Sets a logger.
logging::LoggerPtr	GetLoggerOptional (const std::string &name)
	Returns a logger by its name.
void	StartSocketLoggingDebug (const std::optional< logging::Level > &log_level)
void	StopSocketLoggingDebug (const std::optional< logging::Level > &log_level)
void	OnLogRotate ()
	Reopens log files after rotation.
void	TryReopenFiles ()
void	WriteStatistics (utils::statistics::Writer &writer) const
virtual ComponentHealth	GetComponentHealth () const
virtual void	OnLoadingCancelled ()
virtual void	OnAllComponentsLoaded ()
virtual void	OnAllComponentsAreStopping ()

Static Public Member Functions
static yaml_config::Schema	GetStaticConfigSchema ()

Static Public Attributes
static constexpr std::string_view	kName = "logging"
	The default name of components::Logging component.

Member Function Documentation

GetComponentHealth()

virtual ComponentHealth components::RawComponentBase::GetComponentHealth ( ) const

inlinevirtualinherited

Reimplemented in components::ComponentBase, and server::handlers::Restart.

Definition at line 52 of file raw_component_base.hpp.

GetLogger()

logging::LoggerPtr components::Logging::GetLogger

(

const std::string &

name

)

Returns a logger by its name.

Parameters

name	Name of the logger

Returns

Pointer to the Logger instance

Exceptions

std::runtime_error

if logger with this name is not registered

GetLoggerOptional()

logging::LoggerPtr components::Logging::GetLoggerOptional

(

const std::string &

name

)

Returns a logger by its name.

Parameters

name	Name of the logger

Returns

Pointer to the Logger instance, or nullptr if not registered

GetTextLogger()

logging::TextLoggerPtr components::Logging::GetTextLogger

(

const std::string &

name

)

Returns a text logger by its name.

Parameters

name	Name of the logger

Returns

Pointer to the Logger instance

Exceptions

std::runtime_error	if logger with this name is not registered
std::runtime_error	if logger is not a text logger

OnAllComponentsAreStopping()

virtual void components::RawComponentBase::OnAllComponentsAreStopping ( )

inlinevirtualinherited

Reimplemented in urabbitmq::ConsumerComponentBase, components::ComponentBase, and components::Server.

Definition at line 58 of file raw_component_base.hpp.

OnAllComponentsLoaded()

virtual void components::RawComponentBase::OnAllComponentsLoaded ( )

inlinevirtualinherited

Reimplemented in urabbitmq::ConsumerComponentBase, components::ComponentBase, components::Server, and server::handlers::Ping.

Definition at line 56 of file raw_component_base.hpp.

OnLoadingCancelled()

virtual void components::RawComponentBase::OnLoadingCancelled ( )

inlinevirtualinherited

Reimplemented in components::ComponentBase.

Definition at line 54 of file raw_component_base.hpp.

SetLogger()

void components::Logging::SetLogger	(	const std::string &	name,
		logging::LoggerPtr	logger
	)

Sets a logger.

Parameters

name	Name of the logger
logger	Logger to set

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

• userver/logging/component.hpp