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breakpoint Resource

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To suggest a change, edit the breakpoint.rb file and submit a pull request to the Chef repository.

Resources Reference page


Use the breakpoint resource to add breakpoints to recipes. Run the chef-shell in Chef Infra 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 Infra Client 12.0.

Syntax


The full syntax for all of the properties that are available to the breakpoint resource is:

breakpoint 'name' do
  action      Symbol # defaults to :break if not specified
end

where:

  • breakpoint is the resource.
  • name is the name given to the resource block.
  • action identifies which steps Chef Infra Client will take to bring the node into the desired state.

Actions


The breakpoint resource has the following actions:

:break
:nothing
This resource block does not act unless notified by another resource to take action. Once notified, this resource block either runs immediately or is queued up to run at the end of a Chef Infra 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:

ModeDescription
StandaloneDefault. No cookbooks are loaded, and the run-list is empty.
Solochef-shell acts as a Chef Solo Client. It attempts to load the chef-solo configuration file at ~/.chef/config.rb and any JSON attributes passed. 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.
Clientchef-shell acts as a Chef Infra Client. During startup, it reads the Chef Infra Client configuration file from ~/.chef/client.rb and contacts the Chef Infra Server to get the node's run_list, attributes, and cookbooks. Chef Infra 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. If a NAMED_CONF is given, chef-shell will load ~/.chef/NAMED_CONF/chef_shell.rb
  3. If no NAMED_CONF is given chef-shell will load ~/.chef/chef_shell.rb if it exists
  4. If no chef_shell.rb can be found, chef-shell falls back to load:
    • /etc/chef/client.rb if -z option is given.
    • /etc/chef/solo.rb if –solo-legacy-mode option is given.
    • .chef/config.rb if -s option is given.
    • .chef/knife.rb if -s option is given.

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 Chef Infra Client. For example, to configure chef-shell to authenticate to the Chef Infra Server, copy the node_name, client_key, and chef_server_url settings from the config.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 Infra Client

By default, chef-shell loads in standalone mode and does not connect to the Chef Infra Server. The chef-shell can be run as a Chef Infra Client to verify functionality that is only available when Chef Infra Client connects to the Chef Infra 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 Infra Server. Make sure that the settings in chef-shell.rb are the same as those in config.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 Infra Server, chef-shell can list, show, search for and edit cookbooks, clients, nodes, roles, environments, policyfiles, and data bags.

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

chef-shell -z named_configuration

Where:

  • named_configuration is an existing configuration file in ~/.chef/named_configuration/chef_shell.rb, such as production, staging, or test.

Once in chef-shell, commands can be run against objects as follows:

chef (preprod) > items.command

Where:

  • 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”, enter:

chef (preprod) > nodes.list

Which will 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}" }

will 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')

will return something similar to:

=> node[i-f09a939b]

Or:

chef (preprod) > load_balancer.ec2.public_hostname

will return something similar to:

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

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

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

You can also format the results with a code block. For example:

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

will 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

will 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 Infra 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 Infra 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 Chef Infra Client:

chef:recipe > run_chef
  [Fri, 15 Jan 2020 14:17:49 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2020 14:17:49 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2020 14:17:49 -0800] INFO: Creating file[/tmp/before-breakpoint] at /tmp/before-breakpoint
  [Fri, 15 Jan 2020 14:17:49 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2020 14:17:49 -0800] DEBUG: [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new'] using Chef::Provider::Breakpoint

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

chef:recipe > chef_run.resume
  [Fri, 15 Jan 2020 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

You can rewind and step through a Chef Infra Client run:

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 2020 14:40:52 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2020 14:40:52 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
    => 1
  chef:recipe > chef_run.step
  [Fri, 15 Jan 2020 14:40:54 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2020 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 2020 14:40:56 -0800] DEBUG: Processing file[/tmp/after-breakpoint]
  [Fri, 15 Jan 2020 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, Chef Infra 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 your Chef Infra Client run to get the expected results:

chef:recipe > chef_run.rewind
  chef:recipe > chef_run.resume
  [Fri, 15 Jan 2020 14:48:56 -0800] DEBUG: Processing file[/tmp/before-breakpoint]
  [Fri, 15 Jan 2020 14:48:56 -0800] DEBUG: file[/tmp/before-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2020 14:48:56 -0800] INFO: Creating file[/tmp/before-breakpoint] at /tmp/before-breakpoint
  [Fri, 15 Jan 2020 14:48:56 -0800] DEBUG: Processing [./bin/../lib/chef/mixin/recipe_definition_dsl_core.rb:56:in 'new']
  [Fri, 15 Jan 2020 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 2020 14:49:20 -0800] DEBUG: Processing file[/tmp/after-breakpoint]
  [Fri, 15 Jan 2020 14:49:20 -0800] DEBUG: file[/tmp/after-breakpoint] using Chef::Provider::File
  [Fri, 15 Jan 2020 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.

Welcome to the chef-shell 15.8.23
For usage see https://docs.chef.io/chef_shell.html

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

chef (15.8.23)>

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 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
tracing is on
=> nil
chef >

and:

chef > tracing off
#0:(irb):2:Object:-: tracing off
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:109:Shell::Extensions::ObjectCoreExtensions:>:       def off
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:110:Shell::Extensions::ObjectCoreExtensions:-:         :off
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:111:Shell::Extensions::ObjectCoreExtensions:<:       end
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:272:main:>:       def tracing(on_or_off)
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:273:main:-:         conf.use_tracer = on_or_off.on_off_to_bool
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:162:Shell::Extensions::Symbol:>:       def on_off_to_bool
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:163:Shell::Extensions::Symbol:-:         to_s.on_off_to_bool
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:149:Shell::Extensions::String:>:       def on_off_to_bool
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:150:Shell::Extensions::String:-:         case self
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:154:Shell::Extensions::String:-:           false
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:158:Shell::Extensions::String:<:       end
#0:/opt/chef-workstation/embedded/lib/ruby/gems/2.6.0/gems/chef-15.8.23/lib/chef/shell/ext.rb:164: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 Infra 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 Chef Infra Client is installed using RubyGems or a package manager, chef-shell should already be installed. When Chef Infra 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.

  Welcome to the chef-shell 15.8.23
  For usage see https://docs.chef.io/chef_shell.html

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

  chef (15.8.23)>

(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/username/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 a Chef Infra Client run, use the run_chef command:

chef:recipe_mode > run_chef
  [Fri, 15 Jan 2020 10:42:47 -0800] DEBUG: Processing file[/tmp/ohai2u_shef]
  [Fri, 15 Jan 2020 10:42:47 -0800] DEBUG: file[/tmp/ohai2u_shef] using Chef::Provider::File
  [Fri, 15 Jan 2020 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 Chef Infra Client again:

chef:recipe_mode > run_chef
  [Fri, 15 Jan 2020 10:53:22 -0800] DEBUG: Processing file[/tmp/ohai2u_shef]
  [Fri, 15 Jan 2020 10:53:22 -0800] DEBUG: file[/tmp/ohai2u_shef] using Chef::Provider::File
  [Fri, 15 Jan 2020 10:53:22 -0800] DEBUG: Processing file[/tmp/ohai2u-again]
  [Fri, 15 Jan 2020 10:53:22 -0800] DEBUG: file[/tmp/ohai2u-again] using Chef::Provider::File
  [Fri, 15 Jan 2020 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, Chef Infra 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 the breakpoint resource in recipes:

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

In the following example, the name of each breakpoint is an arbitrary string.

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

In the previous examples, the names are used to indicate if the breakpoint is before or after a resource and also to specify which resource it is before or after.