Class: OpenTrace::TraceFormatter

Inherits:
Object
  • Object
show all
Defined in:
lib/opentrace/trace_formatter.rb

Overview

Wraps an existing log formatter to inject trace context. The injected context appears as a suffix: [trace_id=abc123 request_id=def456]

Usage:

Rails.logger.formatter = OpenTrace::TraceFormatter.new(Rails.logger.formatter)

Instance Method Summary collapse

Constructor Details

#initialize(original_formatter = nil) ⇒ TraceFormatter

Returns a new instance of TraceFormatter.



11
12
13
 
# File 'lib/opentrace/trace_formatter.rb', line 11

def initialize(original_formatter = nil)
  @original = original_formatter || ::Logger::Formatter.new
end

Instance Method Details

#call(severity, datetime, progname, msg) ⇒ Object 



15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
 
# File 'lib/opentrace/trace_formatter.rb', line 15

def call(severity, datetime, progname, msg)
  formatted = @original.call(severity, datetime, progname, msg)
  trace_prefix = build_trace_prefix

  if trace_prefix && formatted.is_a?(String)
    # Append trace context before the trailing newline
    if formatted.end_with?("\n")
      "#{formatted.chomp} #{trace_prefix}\n"
    else
      "#{formatted} #{trace_prefix}"
    end
  else
    formatted
  end
rescue StandardError
  formatted || @original.call(severity, datetime, progname, msg)
end