我有一个工作的Rails 3.2应用程序（Windows Server 2008 R2上的Ruby 1.9.2p290），它使用延迟作业进行多个后台作业。我最近使用log4r替换了Rails默认日志记录，并且它适用于Rails应用程序。但是，当我启动rake jobs:work任务时，我收到一个错误抱怨nil输出器：
Starting job worker rake aborted! TypeError: Expected kind of Outputter, got NilClass F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/log4r-1.1.10/lib/log4r/logger.rb:120:in `each' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/log4r-1.1.10/lib/log4r/logger.rb:120:in `add' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/delayed_job-4.0.0/lib/delayed/worker.rb:248:in `say' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/delayed_job-4.0.0/lib/delayed/worker.rb:147:in `start' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/delayed_job-4.0.0/lib/delayed/tasks.rb:9:in `block (2 levels) in ' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:240:in `call' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:240:in `block in execute' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:235:in `each' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:235:in `execute' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:179:in `block in invoke_with_call_chain' F:/web-shared/Ruby192/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:172:in `invoke_with_call_chain' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/task.rb:165:in `invoke' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:150:in `invoke_task' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:106:in `block (2 levels) in top_level ' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:106:in `each' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:106:in `block in top_level' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:115:in `run_with_threads' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:100:in `top_level' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:78:in `block in run' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:176:in `standard_exception_handling' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/lib/rake/application.rb:75:in `run' F:/web-shared/Ruby192/lib/ruby/gems/1.9.1/gems/rake-10.2.2/bin/rake:33:in `' F:/web-shared/Ruby192/bin/rake:19:in `load' F:/web-shared/Ruby192/bin/rake:19:in `' Tasks: TOP => jobs:work
其他人成功使用log4r延迟工作？我可以使用一些指针;无法通过Google或DuckDuckGo搜索找到任何内容。
以下是config/application.rb摘要：
require File.expand_path('../boot', __FILE__)
require 'erb'
require 'rails/all'
# log4r
require 'log4r'
require 'log4r/yamlconfigurator'
require 'log4r/outputter/datefileoutputter'
require 'log4r/outputter/consoleoutputters'
include Log4r
...
class Application < Rails::Application
...
# assign log4r's logger as rails' logger.
log4r_config = YAML.load(ERB.new(File.read(File.join(File.dirname(__FILE__), 'log4r.yml'))).result)
log4r_config['ENV'] = Rails.env
log4r_config['APPNAME'] = Rails.application.class.parent_name
YamlConfigurator.decode_yaml(log4r_config['log4r_config'])
config.logger = Log4r::Logger[Rails.env]
ActiveRecord::Base.logger = Log4r::Logger[Rails.env]
end
这是config/log4r.yml文件：
log4r_config:
# define all loggers ...
loggers:
- name: production
level: WARN
trace: 'false'
outputters:
- datefile_production
- console_production
- name: development
level: DEBUG
trace: 'true'
outputters:
- datefile_development
- console_development
- name: test
level: DEBUG
trace: 'true'
outputters:
- datefile_test
- console_test
# define all outputters (incl. formatters)
outputters:
- type: DateFileOutputter
name: datefile_production
dirname: "<%= File.join(Rails.root, 'log') %>"
filename: "production.log"
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%X{:remote_ip}\t%X{:user}\t%X{:controller}\t%X{:action}\t%l\t%m'
type: PatternFormatter
- type: DateFileOutputter
name: datefile_development
dirname: "<%= File.join(Rails.root, 'log') %>"
filename: "development.log"
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%X{:remote_ip}\t%X{:user}\t%X{:controller}\t%X{:action}\t%l\t%m'
type: PatternFormatter
- type: DateFileOutputter
name: datefile_test
dirname: "<%= File.join(Rails.root, 'log') %>"
filename: "test.log"
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%X{:remote_ip}\t%X{:user}\t%X{:controller}\t%X{:action}\t%l\t%m'
type: PatternFormatter
- type: StdoutOutputter
name: console_production
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%l\t%m'
type: PatternFormatter
- type: StdoutOutputter
name: console_development
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%X{:remote_ip}\t%X{:user}\t%X{:controller}\t%X{:action}\t%l\t%m'
type: PatternFormatter
- type: StdoutOutputter
name: console_test
formatter:
date_pattern: '%H:%M:%S.%L'
pattern: '%p\t%d\t%X{:remote_ip}\t%X{:user}\t%X{:controller}\t%X{:action}\t%l\t%m'
type: PatternFormatter
更新
好吧，在通过调试器运行rake任务后，我发现了正在发生的事情。
Delayed::Worker（delayed_job/lib/delayed/worker.rb line 248）正在通过记录器的添加方法记录消息，如下所示：
logger.add level, "#{Time.now.strftime('%FT%T%z')}: #{text}" if logger
对于Ruby的Logger类，这是有效且正确的，请参阅Logger.html#method-i-add。但是，通过使用log4r，它会解析为Log4r::Logger.add（log4r/lib/log4r/logger.rb line 119），它会尝试添加输出器。
我不确定为什么会这样，或解决方案是什么。
答案 0 :(得分：1)
您现在可以更新到delayed_jobs 4.0.1 gem，这将解决此问题！
答案 1 :(得分：0)
（有关此问题的原始评论，请参阅blog.mmlac.com。）
问题是DelayedJob期望记录器是Rails :: Logger并调用log4r不支持的记录器。
在本文中，logger变量被覆盖以使用Log4r :: Logger，它不支持.add调用。与Java不同，没有包可以确定要使用哪个记录器类，或者没有用于将不同记录器与标准接口结合的slf4j。
这个问题没有简单的解决方案。一方面，您可以覆盖delayedJob的受影响部分。另一方面，当delayedJob运行rails时，您可以阻止加载log4r，即使用自定义环境：
这也无法保证在任何地方都能正常工作（任何检查rails env ==“production”都会出现问题）。
另一种方法是使用环境变量并检查application.rb中的那些：
if (ENV["log4rlogger"] == "true") config.logger = Log4r::Logger["rails"]