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How do I debug custom functions?

asked 2013-10-11 10:06:56 -0500

robrwo gravatar image

I've written a custom Puppet function in Ruby.

The function works when called used in site.pp, but not when used in any modules.

How do I debug these functions? Is there a way for them to putput diagnostic or debug information?

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answered 2014-02-25 17:24:50 -0500

Stefan gravatar image

Inside your custom function you can use info("some_info)", warning("some_warning") or debug("some_debug") to use the puppet logging function. But be aware that functions are executed on your puppet master, so the log messages will also be logged on your puppet master.

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This doesn't seem to output anything.

robrwo gravatar imagerobrwo ( 2014-03-07 08:37:37 -0500 )edit

You have checked on your puppet master? Depending on where you are logging stuff you'll probably find the output in `/var/log/messages`. Also be aware that when you ...(more)

Stefan gravatar imageStefan ( 2014-03-07 12:13:30 -0500 )edit

answered 2014-01-30 18:43:24 -0500

AronR gravatar image

updated 2014-02-13 22:03:26 -0500

One option might be to experiment with using Ruby's simple, integral Logger class to emit log statements; e.g. something akin to this. (The exact code block below is off the top of my head and untried by me, but follows a pattern I've used elsewhere):

require 'logger'  
module Puppet::Parser::Functions
  newfunction(:yourfunctionname, :type => :rvalue)
  do |args|

    log =
    log.level = Logger::INFO

    # Yes, it makes little sense to log a value just before returning it,
    # since you'll have access to it anyway, but this is just an example ..."myvar ...
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Another potential issue might be the module (or modules) in which your custom function is present; I'm unclear about whether it's possible to invoke a custom function in ...(more)

AronR gravatar imageAronR ( 2014-01-30 20:00:11 -0500 )edit

it basically does not matter in which module you put your custom functions, they can be used everywhere.

Stefan gravatar imageStefan ( 2014-02-25 17:27:14 -0500 )edit

This dosn't work. It does not output anything when I run "puppet agent -t"

robrwo gravatar imagerobrwo ( 2014-03-07 08:22:56 -0500 )edit

Thanks, Stefan, for that information about access to custom functions across modules - it's much appreciated, as are many of your posts and comments here - I've learned a lot ...(more)

AronR gravatar imageAronR ( 2014-03-07 11:22:25 -0500 )edit

@robrwo: It does not output anything when you run `puppet agent -t` because functions are always run on your puppet master when your master compiles the catalog for your node ...(more)

Stefan gravatar imageStefan ( 2014-03-07 13:28:34 -0500 )edit

answered 2014-02-01 05:03:48 -0500

spend gravatar image

Try: function_notice(["Desired is: '#{desired}' "])

or if like me you prefer to write debugging to file then these tend to work'/tmp/myhierapath.log', 'a'){|f| f.print "\nhierarchy:" ; f.write(hierarchy) ;f.print "\n" }

The file method I find better since you don't lose sight of info in logs, and it is together sequentially when you require several debug lines to trace states.

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function_notice does not seem to work

robrwo gravatar imagerobrwo ( 2014-03-07 08:25:24 -0500 )edit

answered 2013-10-12 09:40:07 -0500

bmurts gravatar image

Use puppet agent -td and puppet agent -td --trace to get more detailed output to help debug.

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I've already tried this. It does not give any output about the function at all.

robrwo gravatar imagerobrwo ( 2013-10-14 06:51:56 -0500 )edit

Can you gist your code for the custom function & how it's being used in a module? Please include any errors or warning output from the Puppet runs as well.

bmurts gravatar imagebmurts ( 2013-10-14 07:29:41 -0500 )edit

robrwo gravatar imagerobrwo ( 2013-10-14 11:31:38 -0500 )edit

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Asked: 2013-10-11 10:06:56 -0500

Seen: 5,789 times

Last updated: Feb 25 '14