Class: Traceable::Tracer

Inherits:
Object
  • Object
show all
Defined in:
lib/traceable/tracer.rb

Overview

rubocop:disable Metrics/ClassLength

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(parent_tracer, tags: nil, logger: nil) ⇒ Tracer

Returns a new instance of Tracer.



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# File 'lib/traceable/tracer.rb', line 15

def initialize(parent_tracer, tags: nil, logger: nil)
  @parent = which_parent(parent_tracer)
  @logger = logger || (@parent ? @parent.logger : Tracer.default_logger)
  @tags = @parent ? @parent.tags.dup : Tracer.default_tags
  @tags.merge!(tags) if tags
end

Instance Attribute Details

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/traceable/tracer.rb', line 11

def logger
  @logger
end

#parent ⇒ Object (readonly)

Returns the value of attribute parent.



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# File 'lib/traceable/tracer.rb', line 12

def parent
  @parent
end

#tags ⇒ Object (readonly)

Returns the value of attribute tags.



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# File 'lib/traceable/tracer.rb', line 13

def tags
  @tags
end

Class Method Details

.default_logger ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 22

def self.default_logger
  Traceable.config.logger
end

.default_parent ⇒ Object

rubocop:enable Metrics/AbcSize rubocop:enable Metrics/MethodLength



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# File 'lib/traceable/tracer.rb', line 110

def self.default_parent
  tracer_stack.last # nil if nothing currently on the stack
end

.default_tags ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 26

def self.default_tags
  tags = Traceable.config.default_tags.merge(
    trace: SecureRandom.uuid
  )
  tags.each_key do |k|
    value = tags[k]
    tags[k] = value.call if value.respond_to?(:call)
  end
  tags
end

.tracer_stack ⇒ Object

The tracer stack is a thread-local list of tracer instances, allowing the current tracer context to be automatically inherited by any other tracer instances created further down in the stack.

The current tracer is pushed onto the stack when entering a traced block, then popped from the stack when leaving the traced block.



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# File 'lib/traceable/tracer.rb', line 121

def self.tracer_stack
  Thread.current[:tracer_stack] ||= []
end

Instance Method Details

#debug(msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 70

def debug(msg, **tags)
  emit :debug, msg, **tags
end

#do_block(msg, **tags, &_) ⇒ Object

rubocop:disable Metrics/AbcSize rubocop:disable Metrics/MethodLength



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# File 'lib/traceable/tracer.rb', line 76

def do_block(msg, **tags, &_)
  info "START: #{msg}", enter: true, **tags
  block_start_time = Time.now.utc

  begin
    push
    yield tags
  rescue StandardError => ex
    elapsed = Time.now.utc - block_start_time
    if ex.instance_variable_defined?(:@traceable_rescued)
      origin = ex.instance_variable_get(:@traceable_rescued)
      ex_message = " [propagated from #{origin}]"
    else
      ex.instance_variable_set(:@traceable_rescued, msg)
      ex_message = ", #{ex.message}"
      tags[:backtrace] ||= ex.backtrace.join('\n')
    end

    warn "EXCEPTION: #{msg} => #{ex.class.name}#{ex_message}",
         exception: true, elapsed: elapsed, class: ex.class.name, **tags

    raise
  ensure
    pop

    unless ex
      elapsed = Time.now.utc - block_start_time
      info "END: #{msg}", exit: true, elapsed: elapsed, **tags
    end
  end
end

#emit(method, msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 37

def emit(method, msg, **tags)
  final_tags = make_tags(message: msg, **tags)
  emit_tags(method, final_tags)
end

#emit_tags(method, tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 46

def emit_tags(method, tags)
  logger.send(method, tags)
  nil
rescue StandardError => ex
  warn "EXCEPTION in trace: #{ex}"
  nil
end

#error(msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 58

def error(msg, **tags)
  emit :error, msg, **tags
end

#fatal(msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 54

def fatal(msg, **tags)
  emit :fatal, msg, **tags
end

#info(msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 66

def info(msg, **tags)
  emit :info, msg, **tags
end

#make_tags(**tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 42

def make_tags(**tags)
  @tags.merge(tags)
end

#warn(msg, **tags) ⇒ Object 



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# File 'lib/traceable/tracer.rb', line 62

def warn(msg, **tags)
  emit :warn, msg, **tags
end