Thanks John that did it, your script worked great. Now that I think
about it I see how using facts to generate more facts could cause
these issues.
Nathaniel
On Aug 10, 8:16 am, jcbollinger <john.bollin...@stjude.org> wrote:
> I do not think your problem is related to autosign, but surely that
> would be easy enough to test. More below.
>
> On Aug 9, 6:11 pm, Nathaniel Cook <nvcoo...@gmail.com> wrote:
>
>
>
>
>
>
>
>
>
> > I have run the code by hand and it works just fine. Here it is:
>
> > #################
> > require 'facter'
>
> > def addFact(name , cmd)
> > matches = cmd.scan(/\$\{\w+\}/)
> > if ! matches.empty?
> > for i in 0...matches.length
> > match = matches[i]
> > match = match[2..-2]
> > value = Facter[match].value()
> > if value == nil
> > value = ''
> > end
> > cmd = cmd.gsub(/\$\{#{Regexp.escape(match)}\}/,
> > value)
> > end
> > end
> > Facter.add(name) do
> > setcode do
> > `#{cmd}`.chomp
> > end
> > end
> > end
>
> > #
> > # List of facts to define,
> > #
> > # Can have references to previous facts by using the ${var} syntax
> > #
> > facts = {
> > 'ec2_region' => 'cat /opt/aws/info/region',
> > 'ec2_instance_id' => 'cat /opt/aws/info/instance-id',
> > 'ec2_url' => 'echo
> > "https://ec2.${ec2_region}.amazonaws.com";',
> > 'ec2_zone' => "ec2-metadata -z | awk {'print $NF'}"
> > }
>
> > if ! Facter['ec2_ami_id']
> > puts "Not loading aws_facts"
> > else
>
> > keys = facts.keys
>
> > for key in 0...keys.length
> > fact = keys[key]
> > addFact(fact, facts[fact])
> > end
>
> > end
>
> > ##############
>
> > Its a simple script that sets up some facts about aws ec2 instances.
> > Hope this helps.
>
> I am not convinced that your fact code is in the clear, despite your
> success running it outside a Puppet context. Indeed there's a lot in
> it that I find suspicious, questionable, and / or unsafe, even if it
> turns out not to be responsible for your hang problem:
>
> 1) You use a lot of variables with rather generic names, in scopes
> where they conceivably could collide with variables belonging to
> Facter proper or to Puppet.
>
> 2) I think your setup for interpolating fact values into other fact
> values is too clever by half. I recommend you reserve interpolation
> for Puppet itself to perform. In particular, the ec2_url fact
> provides nothing whatever that wouldn't more appropriately be done by
> Puppet.
>
> 3) If you do retain Facter-side interpolation, then you probably need
> to do it in the fact code itself (i.e. inside the setcode block), as I
> would not expect it to be safe to assume that *any* fact values were
> available at the time that your addFact() funciton is executed.
>
> 4) If you do retain Facter-side interpolation, then you should also
> take the evaluation order of facts into consideration. I do not think
> it safe to assume that that order will be the same as the order in
> which your facts are added, and it certainly is not safe to assume
> that your facts will be added in the order they are listed in your
> hash. If you get lucky, then it might end up working for you --
> perhaps even reliably -- but I could easily imagine that changing with
> addition of more custom facts or with a Facter upgrade. For me, this
> would be a show-stopper.
>
> 5) The reasoning in (4) also suggests that it may not be safe to use
> facts within Facter to determine whether to add other facts (which you
> do). Even if it happens to work now, I would never rely on such
> behavior without solid API documentation supporting it. (Is there
> any?)
>
> Here's how I would write the facts you showed:
>
> ====
>
> Facter.add('ec2_region') do
> setcode do
> `cat /opt/aws/info/region || echo`.chomp
> end
> end
>
> Facter.add('ec2_instance_id') do
> setcode do
> `cat /opt/aws/info/instance-id || echo`.chomp
> end
> end
>
> # ec2_url intentionally omitted
>
> Facter.add('ec2_zone') do
> setcode do
> # Note: you should consider using an explicit path
> # to some or all of the system commands below:
> `ec2-metadata -z | awk {'print $NF'} || echo`.chomp
> end
> end
>
> ====
>
> It's short, sweet, easy to read, and easy to maintain. It also has no
> risk of variable collisions, no evaluation-order dependencies, and it
> works on all nodes, regardless of whether they are ec2.
>
> So, does Puppet still hang if you remove the custom facts? (You'll
> need to both disable pluginsync and manually remove the custom fact
> code from the client, or else make the client sync up a no-op
> version.) If not, then does it hang with my version of them? This
> should give you a good start on debugging.
>
> John
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