Class: SemanticLogger::Appender::File

Inherits:
Subscriber show all
Defined in:
lib/semantic_logger/appender/file.rb

Instance Attribute Summary

Attributes inherited from Subscriber

#application, #formatter, #host, #logger, #metrics

Attributes inherited from Base

#filter, #name

Instance Method Summary collapse

Methods inherited from Subscriber

#close, #default_formatter, #level, #should_log?

Methods inherited from Base

#backtrace, #fast_tag, #level, #level=, #measure, #payload, #pop_tags, #push_tags, #should_log?, #silence, #tagged, #tags, #with_payload

Constructor Details

#initialize(io: nil, file_name: nil, **args, &block) ⇒ File

Create a File Logger appender instance.

Parameters

:file_name [String]
  Name of file to write to.
Or,
:io [IO]
  An IO stream to which to write the log messages to.

:level [:trace | :debug | :info | :warn | :error | :fatal]
  Override the log level for this appender.
  Default: SemanticLogger.default_level

:formatter: [Object|Proc]
  An instance of a class that implements #call, or a Proc to be used to format
  the output from this appender
  Default: Use the built-in formatter (See: #call)

:filter [Regexp|Proc]
  RegExp: Only include log messages where the class name matches the supplied
  regular expression. All other messages will be ignored.
  Proc: Only include log messages where the supplied Proc returns true
        The Proc must return true or false.

Example

require 'semantic_logger'

# Enable trace level logging
SemanticLogger.default_level = :info

# Log to screen
SemanticLogger.add_appender(io: STDOUT, formatter: :color)

# And log to a file at the same time
SemanticLogger.add_appender(file_name: 'application.log', formatter: :color)

logger = SemanticLogger['test']
logger.info 'Hello World'

Example 2. To log all levels to file and only :info and above to screen:

require 'semantic_logger'

# Enable trace level logging
SemanticLogger.default_level = :trace

# Log to screen but only display :info and above
SemanticLogger.add_appender(io: STDOUT, level: :info)

# And log to a file at the same time, including all :trace level data
SemanticLogger.add_appender(file_name: 'application.log')

logger =  SemanticLogger['test']
logger.info 'Hello World'



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# File 'lib/semantic_logger/appender/file.rb', line 62

def initialize(io: nil, file_name: nil, **args, &block)
  if io
    @log = io
  else
    @file_name = file_name
    raise 'SemanticLogging::Appender::File missing mandatory parameter :file_name or :io' unless file_name
    reopen
  end

  super(**args, &block)
end

Instance Method Details

#flush ⇒ Object

Flush all pending logs to disk.

Waits for all sent documents to be writted to disk



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# File 'lib/semantic_logger/appender/file.rb', line 104

def flush
  @log.flush if @log.respond_to?(:flush)
end

#log(log) ⇒ Object

Pass log calls to the underlying Rails, log4j or Ruby logger

trace entries are mapped to debug since :trace is not supported by the
Ruby or Rails Loggers



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# File 'lib/semantic_logger/appender/file.rb', line 94

def log(log)
  # Since only one appender thread will be writing to the file at a time
  # it is not necessary to protect access to the file with a semaphore
  # Allow this logger to filter out log levels lower than it's own
  @log.write(formatter.call(log, self) << "\n")
  true
end

#reopen ⇒ Object

After forking an active process call #reopen to re-open open the file handles etc to resources

Note: This method will only work if :file_name was supplied

on the initializer.
If :io was supplied, it will need to be re-opened manually.



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# File 'lib/semantic_logger/appender/file.rb', line 80

def reopen
  return unless @file_name

  @log = ::File.open(@file_name, ::File::WRONLY | ::File::APPEND | ::File::CREAT)
  # Force all log entries to write immediately without buffering
  # Allows multiple processes to write to the same log file simultaneously
  @log.sync = true
  @log.set_encoding(Encoding::BINARY) if @log.respond_to?(:set_encoding)
  @log
end