Chef Recipe 中的 Ruby 语法

Question

伙计们，我对 ruby 一无所知，但被迫使用 chef recipe .有人可以帮我解决语法问题吗？

当我运行 Recipe 时，这些行导致了问题

old_configs = node["monitoring"]["configs"] || []

异常(exception)是:

NoMethodError: undefined method `[]' for nil:NilClass /var/chef/cache/cookbooks/collectd/recipes/default.rb:100:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/mixin/from_file.rb:30:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/mixin/from_file.rb:30:in `from_file'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/cookbook_version.rb:237:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context.rb:151:in `load_recipe'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context/cookbook_compiler.rb:139:in `block in compile_recipe
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context/cookbook_compiler.rb:137:in `each'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context/cookbook_compiler.rb:137:in `compile_recipes'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context/cookbook_compiler.rb:74:in `compile'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/run_context.rb:86:in `load'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/client.rb:249:in `setup_run_context'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/client.rb:492:in `do_run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/client.rb:199:in `block in run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/client.rb:193:in `fork' 
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/client.rb:193:in `run' 
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/application.rb:183:in `run_chef_client'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/application/client.rb:302:in `block in run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/application/client.rb:294:in `loop'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/application/client.rb:294:in `run_application'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/lib/chef/application.rb:66:in `run'
/opt/chef/embedded/lib/ruby/gems/1.9.1/gems/chef-11.6.0/bin/chef-client:26:in `<top (required)>'

Answer 1

这可能是由于节点“monitoring”属性不存在造成的，你应该先检查节点[“monitoring”]是否存在，然后再尝试查找节点[“monitoring”][“configs”]

简单的方法是:

if node["monitoring"]
  old_configs = node["monitoring"]["configs"] || []
end