[chef] Re: Re: How to mark a ruby_block as failed?

[Dreamcat4 < >]

Well,
Here also is the "eval 'n' converge" helper method for Chef 0.9.12.

# for using within a chef recipe
def eval_and_converge(&blk)
  tmp_run_context = Chef::RunContext.new(node, {})
  tmp_recipe = Chef::Recipe.new(@cookbook_name, @recipe_name, tmp_run_context)
  tmp_recipe.instance_eval(&(blk))
  Chef::Runner.new(tmp_run_context).converge
end

# Or whilst writing your own Chef::Resource and Chef::Provider
class MyProvider < Chef::Provider
  def eval_and_converge(&blk)
    tmp_run_context = Chef::RunContext.new(node, {})
    tmp_recipe = Chef::Recipe.new(@new_resource.cookbook_name,
@new_resource.recipe_name, tmp_run_context)
    tmp_recipe.instance_eval(&(blk))
    Chef::Runner.new(tmp_run_context).converge
  end
end

Does what it says on the tin. It evaluates the &blk passed into it.
Then it converges and executes any chef resources encountered in &blk.

So from the OP's usage example:

ruby block do
  eval_and_converge do
    Chef::Log "Using mdadm..."
    execute "do something"
    # if the previous line of code has returned a non-zero exit code,
    # then Chef will automatically raise an exception for you.
  end
end


Which is the same as:

> ruby_block "A complex operation" do
>  block "using mdadm" do
>    output = `do something`
>    if $?.success?
>      Chef::Log.info output
>    else
>      Chef::Log.error output
>      # tell chef we failed
>    end
>  end
> end

The advantage of eval_and_converge is that you can wrap it around
whichever and as many chef resources you like. It will guarantee those
resources are converged before the next ruby code is encountered. And
it all reads just like a regular chef recipe - the clever shenanigins
is hidden away in the helper method.

On Wed, Dec 22, 2010 at 5:11 PM, Joshua Timberman 
<
 >
 wrote:
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> Here's an example of using an execute resource in a ruby_block. I'm not 
> aware of an easier semantic.
>
> ruby_block "A complex operation" do
>  block do
>    run_context = Chef::RunContext.new(node, {})
>    e = Chef::Resource::Execute.new("Something with mdadm", run_context)
>    e.command("put the command/commands here. multi-line with ruby here 
> document")
>    e.run_action(:run)
>  end
> end
>
> The key here is the run_context and the Chef::Resource syntax.
>
> On Dec 22, 2010, at 8:27 AM, Joshua Timberman wrote:
>
>> Hi there!
>>
>> You can use execute and other resources in ruby_block. It requires setting 
>> the runcontext. I'll paste some code when I get back to my desk.
>>
>> On Dec 21, 2010, at 1:20 PM, Jonathan Weiss 
>> <
 >
>>  wrote:
>>
>>> Cheers,
>>>
>>>
>>> I'm using a ruby_block to handle complex operations with mdadm in
>>> Chef. My question is, how do I tell Chef that my block failed and
>>> execution should halt with an error? In pseudo code:
>>>
>>> ruby_block "A complex operation" do
>>> block "using mdadm" do
>>>   output = `do something`
>>>   if $?.success?
>>>     Chef::Log.info output
>>>   else
>>>     Chef::Log.error output
>>>     # tell chef we failed
>>>   end
>>> end
>>> end
>>>
>>> This would of course be easier if I could just use the execute
>>> resource in the ruby_block...
>>>
>>> Thanks,
>>> Jonathan
>>>
>>> --
>>> Jonathan Weiss
>>> http://blog.innerewut.de
>>> http://twitter.com/jweiss
>
> - --
> Opscode, Inc
> Joshua Timberman, Technical Evangelist
> IRC, Skype, Twitter, Github: jtimberman
>
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