Logging component 
Allows to configure the default logger and/or additional loggers for your needs.
Static options:
| Name    | Description    | Default value     | 
| file_path    | path to the log file    | -     | 
| level    | log verbosity    | info     | 
| format    | log output format, either tskv or ltsv    | tskv     | 
| flush_level    | messages of this and higher levels get flushed to the file immediately    | warning     | 
| message_queue_size    | the size of internal message queue, must be a power of 2    | 65536     | 
| overflow_behavior    | message handling policy while the queue is full: discard drops messages, block waits until message gets into the queue    | discard     | 
| testsuite-capture    | if exists, setups additional TCP log sink for testing purposes    | {}     | 
| fs-task-processor    | task processor for disk I/O operations for this logger    | fs-task-processor of the loggers component    | 
Logs output
You can specify logger output, in file_path option:
- Use 
@stdout to write your logs to standard output stream; 
- Use 
@stderr to write your logs to standard error stream; 
- Use 
@null to suppress sending of logs; 
- Use 
file_name% to write your logs in file. Use USR1 signal or OnLogRotate handler to reopen files after log rotation; 
- Use 
unix:socket_name% to write your logs to unix socket. Socket must be created before the service starts and closed by listener afert service is shuted down. 
testsuite-capture options:
| Name    | Description    | Default value     | 
| host    | testsuite hostname, e.g. localhost    | -     | 
| port    | testsuite port    | -    | 
Static configuration example:
# yaml
    logging:
      fs-task-processor: fs-task-processor
      loggers:
        access:
          file_path: $access_log_path
          overflow_behavior: discard
          format: raw
        access-tskv:
          file_path: $access_tskv_log_path
          overflow_behavior: discard
          format: raw
        default:
          file_path: $default_log_path
          level: $log_level
          level#fallback: debug
          overflow_behavior: discard
        tracer:
          file_path: '@stdout'
          overflow_behavior: discard
default section configures the default logger for LOG_*. 
Definition at line 79 of file component.hpp.
 
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  | Logging (const ComponentConfig &, const ComponentContext &) | 
|   | The component constructor. 
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| logging::LoggerPtr  | GetLogger (const std::string &name) | 
|   | Returns a logger by its name.  
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| logging::LoggerPtr  | GetLoggerOptional (const std::string &name) | 
|   | Returns a logger by its name.  
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void  | StartSocketLoggingDebug (const std::optional< logging::Level > &log_level) | 
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void  | StopSocketLoggingDebug (const std::optional< logging::Level > &log_level) | 
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void  | OnLogRotate () | 
|   | Reopens log files after rotation. 
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void  | TryReopenFiles () | 
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void  | WriteStatistics (utils::statistics::Writer &writer) const | 
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