Class: PerfCheck::Middleware

Inherits:
Object
  • Object
show all
Defined in:
lib/perf_check/middleware.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Middleware

Returns a new instance of Middleware.



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# File 'lib/perf_check/middleware.rb', line 8

def initialize(app)
  @app = app

  self.query_count = 0
  ActiveSupport::Notifications.subscribe('sql.active_record') do |_|
    self.query_count += 1
  end
end

Instance Attribute Details

#app ⇒ Object (readonly)

Returns the value of attribute app.



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# File 'lib/perf_check/middleware.rb', line 5

def app
  @app
end

#query_count ⇒ Object

Returns the value of attribute query_count.



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# File 'lib/perf_check/middleware.rb', line 6

def query_count
  @query_count
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/perf_check/middleware.rb', line 17

def call(env)
  self.query_count = 0

  begin
    status, headers, body = app.call(env)
  rescue => error
    status, headers, body = 500, { "X-PerfCheck-StackTrace" => stacktrace_for(error) }, ['']
  end
  headers['X-PerfCheck-Query-Count'] = query_count.to_s
  [status, headers, body]
end

#stacktrace_for(e) ⇒ Object

These files are used by the perf_check daemon app



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# File 'lib/perf_check/middleware.rb', line 30

def stacktrace_for(e)
  trace_file = "#{Rails.root}/tmp/perf_check_traces" <<
               "/trace-#{SecureRandom.hex(16)}.txt"
  FileUtils.mkdir_p(File.dirname(trace_file))

  File.open(trace_file, 'w') do |f|
    f.puts("#{e.class}: #{e.message}")
    f.write(e.backtrace.join("\n"))
  end
  trace_file
end