breakpoint

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Use the breakpoint resource to add breakpoints to recipes. Run the chef-shell in chef-client mode, and then use those breakpoints to debug recipes. Breakpoints are ignored by the chef-client during an actual chef-client run. That said, breakpoints are typically used to debug recipes only when running them in a non-production environment, after which they are removed from those recipes before the parent cookbook is uploaded to the Chef server.

New in Chef Client 12.0.

Syntax

A breakpoint resource block creates a breakpoint in a recipe:

breakpoint 'name' do
  action :break
end

where

  • :break will tell the chef-client to stop running a recipe; can only be used when the chef-client is being run in chef-shell mode

Actions

This resource has the following actions:

:break
Use to add a breakpoint to a recipe.
:nothing
Define this resource block to do nothing until notified by another resource to take action. When this resource is notified, this resource block is either run immediately or it is queued up to be run at the end of the chef-client run.

Properties

This resource does not have any properties.

Debug Recipes with chef-shell

chef-shell is a recipe debugging tool that allows the use of breakpoints within recipes. chef-shell runs as an Interactive Ruby (IRb) session. chef-shell supports both recipe and attribute file syntax, as well as interactive debugging features.

Modes

chef-shell is tool that is run using an Interactive Ruby (IRb) session. chef-shell currently supports recipe and attribute file syntax, as well as interactive debugging features. chef-shell has three run modes:

Mode Description
Standalone Default. No cookbooks are loaded, and the run-list is empty.
Solo chef-shell acts as a chef-solo client. It attempts to load the chef-solo configuration file and JSON attributes. If the JSON attributes set a run-list, it will be honored. Cookbooks will be loaded in the same way that chef-solo loads them. chef-solo mode is activated with the -s or --solo command line option, and JSON attributes are specified in the same way as for chef-solo, with -j /path/to/chef-solo.json.
Client chef-shell acts as a chef-client. During startup, it reads the chef-client configuration file and contacts the Chef server to get attributes and cookbooks. The run-list will be set in the same way as normal chef-client runs. chef-client mode is activated with the -z or --client options. You can also specify the configuration file with -c CONFIG and the server URL with -S SERVER_URL.

Configure

chef-shell determines which configuration file to load based on the following:

  1. If a configuration file is specified using the -c option, chef-shell will use the specified configuration file
  2. When chef-shell is started using a named configuration as an argument, chef-shell will search for a chef-shell.rb file in that directory under ~/.chef. For example, if chef-shell is started using production as the named configuration, the chef-shell will load a configuration file from ~/.chef/production/chef_shell.rb
  3. If a named configuration is not provided, chef-shell will attempt to load the chef-shell.rb file from the .chef directory. For example: ~/.chef/chef_shell.rb
  4. If a chef-shell.rb file is not found, chef-shell will attempt to load the client.rb file
  5. If a chef-shell.rb file is not found, chef-shell will attempt to load the solo.rb file

chef-shell.rb

The chef-shell.rb file can be used to configure chef-shell in the same way as the client.rb file is used to configure the chef-client. For example, to configure chef-shell to authenticate to the Chef server, copy the node_name, client_key, and chef_server_url settings from the knife.rb file:

node_name                'your-knife-clientname'
client_key               File.expand_path('~/.chef/my-client.pem')
chef_server_url          'https://api.opscode.com/organizations/myorg'

and then add them to the chef-shell.rb file. Other configuration possibilities include disabling Ohai plugins (which will speed up the chef-shell boot process) or including arbitrary Ruby code in the chef-shell.rb file.

Run as a chef-client

By default, chef-shell loads in standalone mode and does not connect to the Chef server. The chef-shell can be run as a chef-client to verify functionality that is only available when the chef-client connects to the Chef server, such as search functionality or accessing data stored in data bags.

chef-shell can use the same credentials as knife when connecting to a Chef server. Make sure that the settings in chef-shell.rb are the same as those in knife.rb, and then use the -z option as part of the command. For example:

$ chef-shell -z

Manage

When chef-shell is configured to access a Chef server, chef-shell can list, show, search for and edit cookbooks, clients, nodes, roles, environments, and data bags.

The syntax for managing objects on the Chef server is as follows:

$ chef (named_configuration) > items.command

where:

  • named_configuration is a named configuration, such as production, staging, or test
  • items is the type of item to search for: cookbooks, clients, nodes, roles, environments or a data bag
  • command is the command: list, show, find, or edit

For example, to list all of the nodes in a configuration named “preprod”:

$ chef (preprod) > nodes.list

to return something similar to:

$ => [node[i-f09a939b], node[i-049a936f], node[i-eaaaa581], node[i-9154b1fb],
     node[i-6a213101], node[i-c2687aa9], node[i-7abeaa11], node[i-4eb8ac25],
     node[i-9a2030f1], node[i-a06875cb], node[i-145f457f], node[i-e032398b],
     node[i-dc8c98b7], node[i-6afdf401], node[i-f49b119c], node[i-5abfab31],
     node[i-78b8ac13], node[i-d99678b3], node[i-02322269], node[i-feb4a695],
     node[i-9e2232f5], node[i-6e213105], node[i-cdde3ba7], node[i-e8bfb083],
     node[i-743c2c1f], node[i-2eaca345], node[i-aa7f74c1], node[i-72fdf419],
     node[i-140e1e7f], node[i-f9d43193], node[i-bd2dc8d7], node[i-8e7f70e5],
     node[i-78f2e213], node[i-962232fd], node[i-4c322227], node[i-922232f9],
     node[i-c02728ab], node[i-f06c7b9b]]

The list command can take a code block, which will applied (but not saved) to each object that is returned from the server. For example:

$ chef (preprod) > nodes.list {|n| puts "#{n.name}: #{n.run_list}" }

to return something similar to:

$ => i-f09a939b: role[lb], role[preprod], recipe[aws]
     i-049a936f: role[lb], role[preprod], recipe[aws]
     i-9154b1fb: recipe[erlang], role[base], role[couchdb], role[preprod],
     i-6a213101: role[chef], role[preprod]
     # more...

The show command can be used to display a specific node. For example:

$ chef (preprod) > load_balancer = nodes.show('i-f09a939b')

to return something similar to:

$ => node[i-f09a939b]

or:

$ chef (preprod) > load_balancer.ec2.public_hostname

to return something similar to:

$ => "ec2-111-22-333-44.compute-1.amazonaws.com"

The find command can be used to search the Chef server from the chef-shell. For example:

$ chef (preprod) > pp nodes.find(:ec2_public_hostname => 'ec2*')

A code block can be used to format the results. For example:

$ chef (preprod) > pp nodes.find(:ec2_public_hostname => 'ec2*') {|n| n.ec2.ami_id } and nil

to return something similar to:

$ => ["ami-f8927a91",
      "ami-f8927a91",
      "ami-a89870c1",
      "ami-a89870c1",
      "ami-a89870c1",
      "ami-a89870c1",
      "ami-a89870c1"
      # and more...

Or:

chef (preprod) > amis = nodes.find(:ec2_public_hostname => 'ec2*') {|n| n.ec2.ami_id }
chef (preprod) > puts amis.uniq.sort

to return something similar to:

$ => ami-4b4ba522
     ami-a89870c1
     ami-eef61587
     ami-f8927a91

Use Breakpoints

chef-shell allows the current position in a run-list to be manipulated during a chef-client run. Add breakpoints to a recipe to take advantage of this functionality.

Step Through Run-list

To explore how using the breakpoint to manually step through a chef-client run, create a simple recipe in chef-shell:

$ chef > recipe_mode
  chef:recipe > echo off
  chef:recipe > file "/tmp/before-breakpoint"
  chef:recipe > breakpoint "foo"
  chef:recipe > file "/tmp/after-breakpoint"

and then run the chef-client:

$ chef:recipe > run_chef
  [Fri, 15 Jan 2010 14:17:49 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2010 14:17:49 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2010 14:17:49 -0800] INFO: Creating file[/tmp/before-breakpoint] at /tmp/before-breakpoint
  [Fri, 15 Jan 2010 14:17:49 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2010 14:17:49 -0800] DEBUG: [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new'] using Chef::Provider::Breakpoint

The chef-client ran the first resource before the breakpoint (file[/tmp/before-breakpoint]), but then stopped after execution. The chef-client attempted to name the breakpoint after its position in the source file, but the chef-client was confused because the resource was entered interactively. From here, chef-shell can resume the chef-client run:

$ chef:recipe > chef_run.resume
  [Fri, 15 Jan 2010 14:27:08 -0800] INFO: Creating file[/tmp/after-breakpoint] at /tmp/after-breakpoint

A quick view of the /tmp directory shows that the following files were created:

after-breakpoint
before-breakpoint

The chef-client run can also be rewound, and then stepped through.

$ chef:recipe > Chef::Log.level = :debug # debug logging won't turn on automatically in this case
    => :debug
  chef:recipe > chef_run.rewind
    => 0
  chef:recipe > chef_run.step
  [Fri, 15 Jan 2010 14:40:52 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2010 14:40:52 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
    => 1
  chef:recipe > chef_run.step
  [Fri, 15 Jan 2010 14:40:54 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2010 14:40:54 -0800] DEBUG: [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new'] using Chef::Provider::Breakpoint
    => 2
  chef:recipe > chef_run.step
  [Fri, 15 Jan 2010 14:40:56 -0800] DEBUG: Processing file[/tmp/after-breakpoint]
  [Fri, 15 Jan 2010 14:40:56 -0800] DEBUG: file[/tmp/after-breakpoint] using Chef::Provider::File
    => 3

From the output, the rewound run-list is shown, but when the resources are executed again, they will repeat their checks for the existence of files. If they exist, the chef-client will skip creating them. If the files are deleted, then:

$ chef:recipe > ls("/tmp").grep(/breakpoint/).each {|f| rm "/tmp/#{f}" }
    => ["after-breakpoint", "before-breakpoint"]

Rewind, and then resume the chef-client run to get the expected results:

$ chef:recipe > chef_run.rewind
  chef:recipe > chef_run.resume
  [Fri, 15 Jan 2010 14:48:56 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2010 14:48:56 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2010 14:48:56 -0800] INFO: Creating file[/tmp/before-breakpoint] at /tmp/before-breakpoint
  [Fri, 15 Jan 2010 14:48:56 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2010 14:48:56 -0800] DEBUG: [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new'] using Chef::Provider::Breakpoint
  chef:recipe > chef_run.resume
  [Fri, 15 Jan 2010 14:49:20 -0800] DEBUG: Processing file[/tmp/after-breakpoint]
  [Fri, 15 Jan 2010 14:49:20 -0800] DEBUG: file[/tmp/after-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2010 14:49:20 -0800] INFO: Creating file[/tmp/after-breakpoint] at /tmp/after-breakpoint

Debug Existing Recipe

chef-shell can be used to debug existing recipes. The recipe first needs to be added to a run-list for the node, so that it is cached when starting chef-shell and then used for debugging. chef-shell will report which recipes are being cached when it is started:

loading configuration: none (standalone session)
Session type: standalone
Loading..............done.

This is the chef-shell.
 Chef Version: 12.17.44
 https://www.chef.io/
 /

run `help' for help, `exit' or ^D to quit.

Ohai2u YOURNAME@!
chef (12.17.44)>

To just load one recipe from the run-list, go into the recipe and use the include_recipe command. For example:

$ chef > recipe_mode
  chef:recipe > include_recipe "getting-started"
    => [#<Chef::Recipe:0x10256f9e8 @cookbook_name="getting-started",
  ... output truncated ...

To load all of the recipes from a run-list, use code similar to the following:

node.run_list.expand(node.chef_environment).recipes.each do |r|
  include_recipe r
end

After the recipes that are to be debugged have been loaded, use the run_chef command to run them.

Advanced Debugging

In chef-shell, it is possible to get extremely verbose debugging using the tracing feature in Interactive Ruby (IRb). chef-shell provides a shortcut for turning tracing on and off. For example:

$ chef > tracing on
  /Users/danielsdeleo/.rvm/ree-1.8.7-2009.10/lib/ruby/1.8/tracer.rb:150: warning: tried to create Proc object without a block
  /Users/danielsdeleo/.rvm/ree-1.8.7-2009.10/lib/ruby/1.8/tracer.rb:146: warning: tried to create Proc object without a block
  tracing is on
    => nil

and:

$ chef > tracing off
  #0:(irb):3:Object:-: tracing off
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:108:Shell::Extensions::ObjectCoreExtensions:>:       def off
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:109:Shell::Extensions::ObjectCoreExtensions:-:         :off
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:110:Shell::Extensions::ObjectCoreExtensions:<:       end
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:273:main:>:       def tracing(on_or_off)
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:274:main:-:         conf.use_tracer = on_or_off.on_off_to_bool
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:161:Shell::Extensions::Symbol:>:       def on_off_to_bool
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:162:Shell::Extensions::Symbol:-:         self.to_s.on_off_to_bool
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:148:Shell::Extensions::String:>:       def on_off_to_bool
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:149:Shell::Extensions::String:-:         case self
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:153:Shell::Extensions::String:-:           false
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:157:Shell::Extensions::String:<:       end
  #0:/opt/chef/embedded/lib/ruby/gems/1.9.3/gems/chef-11.4.4/lib/chef/shell/ext.rb:163:Shell::Extensions::Symbol:<:       end
  tracing is off
   => nil
  chef >

Debug Examples

The following examples show how to use chef-shell.

“Hello World”

This example shows how to run chef-shell in standalone mode. (For chef-solo or chef-client modes, you would need to run chef-shell using the -s or -z command line options, and then take into consideration the necessary configuration settings.)

When the chef-client is installed using RubyGems or a package manager, chef-shell should already be installed. When the chef-client is run from a git clone, it will be located in chef/bin/chef shell. To start chef-shell, just run it without any options. You’ll see the loading message, then the banner, and then the chef-shell prompt:

$ bin/chef-shell
  loading configuration: none (standalone session)
  Session type: standalone
  Loading..............done.

  This is the chef-shell.
   Chef Version: 12.17.44
   https://www.chef.io/
   /

  run `help' for help, `exit' or ^D to quit.

  Ohai2u YOURNAME@!
  chef (12.17.44)>

(Use the help command to print a list of supported commands.) Use the recipe_mode command to switch to recipe context:

$ chef > recipe_mode
  chef:recipe_mode >

Typing is evaluated in the same context as recipes. Create a file resource:

$ chef:recipe_mode > file "/tmp/ohai2u_shef"
    => #<Chef::Resource::File:0x1b691ac
       @enclosing_provider=nil,
       @resource_name=:file,
       @before=nil,
       @supports={},
       @backup=5,
       @allowed_actions=[:nothing, :create, :delete, :touch, :create_if_missing],
       @only_if=nil,
       @noop=nil,
       @collection=#<Chef::ResourceCollection:0x1b9926c
       @insert_after_idx=nil,
       @resources_by_name={"file[/tmp/ohai2u_shef]"=>0},
       @resources=[#<Chef::Resource::File:0x1b691ac ...>]>,
       @updated=false,
       @provider=nil,
       @node=<Chef::Node:0xdeeaae
       @name="eigenstate.local">,
       @recipe_name=nil,
       @not_if=nil,
       @name="/tmp/ohai2u_shef",
       @action="create",
       @path="/tmp/ohai2u_shef",
       @source_line="/Users/danielsdeleo/ruby/chef/chef/(irb#1) line 1",
       @params={},
       @actions={},
       @cookbook_name=nil,
       @ignore_failure=false>

(The previous example was formatted for presentation.) At this point, chef-shell has created the resource and put it in the run-list, but not yet created the file. To initiate the chef-client run, use the run_chef command:

$ chef:recipe_mode > run_chef
  [Fri, 15 Jan 2010 10:42:47 -0800] DEBUG: Processing file[/tmp/ohai2u_shef]
  [Fri, 15 Jan 2010 10:42:47 -0800] DEBUG: file[/tmp/ohai2u_shef] using Chef::Provider::File
  [Fri, 15 Jan 2010 10:42:47 -0800] INFO: Creating file[/tmp/ohai2u_shef] at /tmp/ohai2u_shef
    => true

chef-shell can also switch to the same context as attribute files. Set an attribute with the following syntax:

$ chef:recipe_mode > attributes_mode
  chef:attributes > set[:hello] = "ohai2u-again"
    => "ohai2u-again"
  chef:attributes >

Switch back to recipe_mode context and use the attributes:

$ chef:attributes > recipe_mode
    => :attributes
  chef:recipe_mode > file "/tmp/#{node.hello}"

Now, run the chef-client again:

$ chef:recipe_mode > run_chef
  [Fri, 15 Jan 2010 10:53:22 -0800] DEBUG: Processing file[/tmp/ohai2u_shef]
  [Fri, 15 Jan 2010 10:53:22 -0800] DEBUG: file[/tmp/ohai2u_shef] using Chef::Provider::File
  [Fri, 15 Jan 2010 10:53:22 -0800] DEBUG: Processing file[/tmp/ohai2u-again]
  [Fri, 15 Jan 2010 10:53:22 -0800] DEBUG: file[/tmp/ohai2u-again] using Chef::Provider::File
  [Fri, 15 Jan 2010 10:53:22 -0800] INFO: Creating file[/tmp/ohai2u-again] at /tmp/ohai2u-again
    => true
  chef:recipe_mode >

Because the first resource (file[/tmp/ohai2u_shef]) is still in the run-list, it gets executed again. And because that file already exists, the chef-client doesn’t attempt to re-create it. Finally, the files were created using the ls method:

$ chef:recipe_mode > ls("/tmp").grep(/ohai/)
    => ["ohai2u-again", "ohai2u_shef"]
      Shell Tutorial

Get Specific Nodes

To get a list of nodes using a recipe named postfix use search(:node,"recipe:postfix"). To get a list of nodes using a sub-recipe named delivery, use chef-shell. For example:

search(:node, 'recipes:postfix\:\:delivery')

Note

Single (‘ ‘) vs. double (” ”) is important. This is because a backslash () needs to be included in the string, instead of having Ruby interpret it as an escape.

Examples

The following examples demonstrate various approaches for using resources in recipes. If you want to see examples of how Chef uses resources in recipes, take a closer look at the cookbooks that Chef authors and maintains: https://github.com/chef-cookbooks.

A recipe without a breakpoint

yum_key node['yum']['elrepo']['key'] do
  url  node['yum']['elrepo']['key_url']
  action :add
end

yum_repository 'elrepo' do
  description 'ELRepo.org Community Enterprise Linux Extras Repository'
  key node['yum']['elrepo']['key']
  mirrorlist node['yum']['elrepo']['url']
  includepkgs node['yum']['elrepo']['includepkgs']
  exclude node['yum']['elrepo']['exclude']
  action :create
end

The same recipe with breakpoints

breakpoint "before yum_key node['yum']['repo_name']['key']" do
  action :break
end

yum_key node['yum']['repo_name']['key'] do
  url  node['yum']['repo_name']['key_url']
  action :add
end

breakpoint "after yum_key node['yum']['repo_name']['key']" do
  action :break
end

breakpoint "before yum_repository 'repo_name'" do
  action :break
end

yum_repository 'repo_name' do
  description 'description'
  key node['yum']['repo_name']['key']
  mirrorlist node['yum']['repo_name']['url']
  includepkgs node['yum']['repo_name']['includepkgs']
  exclude node['yum']['repo_name']['exclude']
  action :create
end

breakpoint "after yum_repository 'repo_name'" do
  action :break
end

where the name of each breakpoint is an arbitrary string. In the previous examples, the names are used to indicate if the breakpoint is before or after a resource, and then also to specify which resource.