設置廚師變量通過ruby_block沒有被執行

Question

我想實現一個系統，其中，因爲應用程序跨多個節點需要相同的用戶ID，我們做一個小型的MySQL表上查找具有應用程序名稱和相應的ID存儲在自動增量表中。如果用戶標識不存在，我們創建它並返回。由於「數據庫」食譜遇到的問題，我決定在bash腳本中實現Mysql查詢，該腳本將UID返回給Stdout，並讓Chef在創建用戶時使用該查詢。作爲Mysql腳本的一個參數，我們提供我們要發佈的apllication名稱的節點屬性，這是在數據庫中搜索的條目。

我遇到的問題是我試圖通過ruby_block設置變量，這似乎並沒有被處理。廚師日誌顯示變量沒有被設置，當我完全從等式中刪除了mysql腳本時，它仍然沒有被設置。據我瞭解，這是相當簡單的語法，所以可以看出爲什麼這是失敗的。下面的代碼：

define :create_application_ids do 

    # Assign variable names to the parameters passed. 
    application = params[:application_name] 

    # Set the fail flag to zero. 
    node.default[:deploy][application][:fail] = 0 

    # Deploy our mysql query script to get (or create, if required) a user ID for the application 
    template "query_mysql.bash" do 
     path "/root/query_mysql.bash" 
     source "query_mysql.bash.erb" 
     owner "root" 
     group "root" 
     mode "0750" 
    end 

    ruby_block "set_app_id" do 
    block do 
    id = `/root/query_mysql.bash #{node[:deploy][application]}` 
    end 
    action :create 
    end 

    Chef::Log.info "MY-DEPLOY: The ID variable is #{id}" 

    # If a user and group ID has been specified in the JSON string for the 
    # application, then create them both. 

    if (defined?(id)) 
    directory node[:deploy][application][:home_dir] do 
     owner "root" 
     group "root" 
     mode 0777 
     recursive true 
     action :create 
    end 

    group "#{node[:deploy][application][:group_name]}" do 
     gid id 
     only_if { `cat /etc/group | grep -E '^#{node[:deploy][application][:group_name]}:'` } 
    end 

    user "#{node[:deploy][application][:user_name]}" do 
     uid id 
     gid node[:deploy][application][:group_name] 
     home "#{node[:deploy][application][:home_dir]}" 
     shell "/sbin/nologin" 
     only_if { `cat /etc/passwd | grep -E '^#{node[:deploy][application][:user_name]}:'` } 
    end 

    # Create any standard directories for the user. 
    create_application_dirs do 
     application_name application 
    end 

    else 

     Chef::Log.info "MY: #{node[:deploy][application]}" 
    # Since this failed, set the fail flag to 1. 
    node.default[:deploy][application][:fail] = 1 

    log "message" do 
     message "MY-DEPLOY: Cannot deploy application without unique user and group ID" 
     level :fatal 
    end 

    end 

end 

，我看到了這個在廚師輸出：

Recipe Compile Error in /var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/recipes/repository.rb 
================================================================================ 


NameError 
--------- 
No resource, method, or local variable named `id' for `Chef::Recipe "repository"' 


Cookbook Trace: 
--------------- 
/var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/definitions/create_application_ids.rb:25:in `block in from_file' 
/var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/recipes/repository.rb:15:in `block in from_file' 
/var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/recipes/repository.rb:2:in `each' 
/var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/recipes/repository.rb:2:in `from_file' 


Relevant File Content: 
---------------------- 
/var/lib/aws/opsworks/cache.stage2/cookbooks/my-deploy/definitions/create_application_ids.rb: 

18: ruby_block "set_app_id" do 
19: block do 
20:  id = `/root/query_mysql.bash #{node[:deploy][application]}` 
21: end 
22: action :create 
23: end 
24: 
25>> Chef::Log.info "MY-DEPLOY: The ID variable is #{id}" 
26: 
27: # If a user and group ID has been specified in the JSON string for the 
28: # application, then create them both. 
29: 
30: if (defined?(id)) 
31:  directory node[:deploy][application][:home_dir] do 
32:  owner "root" 
33:  group "root" 
34:  mode 0777 



[2014-10-08T00:55:49+11:00] ERROR: Running exception handlers 
[2014-10-08T00:55:49+11:00] ERROR: Exception handlers complete 
[2014-10-08T00:55:49+11:00] FATAL: Stacktrace dumped to /var/lib/aws/opsworks/cache.stage2/chef-stacktrace.out 
[2014-10-08T00:55:50+11:00] ERROR: No resource, method, or local variable named `id' for `Chef::Recipe "repository"' 
[2014-10-08T00:55:50+11:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process exited unsuccessfully (exit code 1) 

Answer 1

Tensibai的回答非常好，我建議你接受它。也就是說，我個人的口味是採取稍微不同的方法。

廚師服務器的一個巨大的好處是能夠搜索。因此，我會將id放在節點屬性中，而不是獨立屬性中，然後將其用於lazy evaluation。

define :create_application_ids do 

    # Assign variable names to the parameters passed. 
    application = params[:application_name] 

    # Set the fail flag to zero. 
    node.default[:deploy][application][:fail] = 0 

    # Deploy our mysql query script to get (or create, if required) a user ID for the application 
    template "query_mysql.bash" do 
     path "/root/query_mysql.bash" 
     source "query_mysql.bash.erb" 
     owner "root" 
     group "root" 
     mode "0750" 
    end 

    ruby_block "set_app_id" do 
    block do 
     node[application][:id] = `/root/query_mysql.bash #{node[:deploy][application]}` 
    end 
    action :create 
    not_if node[application] && node[application][:id] 
    end 

    Chef::Log.info "MY-DEPLOY: The ID variable is #{id}" 

    # If a user and group ID has been specified in the JSON string for the 
    # application, then create them both. 

    directory node[:deploy][application][:home_dir] do 
    owner "root" 
    group "root" 
    mode 0777 
    recursive true 
    action :create 
    end 

    group "#{node[:deploy][application][:group_name]}" do 
    gid lazy{ node[application][:id] } 
    only_if { `cat /etc/group | grep -E '^#{node[:deploy][application][:group_name]}:'` } 
    end 

    user "#{node[:deploy][application][:user_name]}" do 
    uid lazy { node[application][:id] } 
    gid node[:deploy][application][:group_name] 
    home "#{node[:deploy][application][:home_dir]}" 
    shell "/sbin/nologin" 
    only_if { `cat /etc/passwd | grep -E '^#{node[:deploy][application][:user_name]}:'` } 
    end 

    # Create any standard directories for the user. 
    create_application_dirs do 
    application_name application 
    end 
end 

Answer 2

你打一個廚師運行問題的兩個階段。請參閱documentation about it here

首先編譯配方/定義並製作資源「堆棧」。

Lwrp將通過正確參數調用資源（在收斂時間）進行評估來解決您的問題。

在這裏對您的定義進行評估，創建一個類型爲ruby_block的資源，該資源將在收斂時執行。

在定義此資源之後，您將測試是否定義了id，但您的ruby_block此時尚未運行。

你必須改變你的代碼，去掉if (defined?(id))。 您在下面使用的資源已具有冪等性（不需要用戶和組資源中的only_if）。

但是，你必須使用懶惰的評估ID在資源，以避免讓他們定義爲零代替你的ID。

即

group "#{node[:deploy][application][:group_name]}" do 
    gid lazy { id } 
    only_if { `cat /etc/group | grep -E '^#{node[:deploy][application][:group_name]}:'` } 
end 

如果你真的想找出錯誤並打印您可以使用一個開始/救援塊自定義消息，如無ID的組或用戶資源將拋出一個異常IIRC。