Class: Puppet::Provider
- Extended by:
- Confiner, Util, Util::Docs, Util::Logging, Util::Warnings
- Includes:
- Comparable, Util, Util::Errors, Util::Warnings
- Defined in:
- lib/puppet/provider.rb
Overview
An instance of a Provider is associated with one resource.
Class level methods are only called once to configure the provider (when the type is created), and not for each resource the provider is operating on. The instance methods are however called for each resource.
A Provider is an implementation of the actions that manage resources (of some type) on a system. This class is the base class for all implementation of a Puppet Provider.
Concepts: –
-
Confinement - confinement restricts providers to only be applicable under certain conditions.
It is possible to confine a provider several different ways: * the included {#confine} method which provides filtering on fact, feature, existence of files, or a free form predicate. * the {commands} method that filters on the availability of given system commands.
-
**Property hash** - the important instance variable ‘@property_hash` contains all current state values for properties (it is lazily built). It is important that these values are managed appropriately in the methods Provider.instances, Provider.prefetch, and in methods that alters the current state (those that change the lifecycle (creates, destroys), or alters some value reflected backed by a property).
-
Flush - is a hook that is called once per resource when everything has been applied. The intent is that an implementation may defer modification of the current state typically done in property setters and instead record information that allows flush to perform the changes more efficiently.
-
**Execution Methods** - The execution methods provides access to execution of arbitrary commands. As a convenience execution methods are available on both the instance and the class of a provider since a lot of provider logic switch between these contexts fairly freely.
-
**System Entity/Resource** - this documentation uses the term “system entity” for system resources to make it clear if talking about a resource on the system being managed (e.g. a file in the file system) or about a description of such a resource (e.g. a Puppet Resource).
-
**Resource Type** - this is an instance of Type that describes a classification of instances of Resource (e.g. the ‘File` resource type describes all instances of `file` resources). (The term is used to contrast with “type” in general, and specifically to contrast with the implementation class of Resource or a specific Type).
Direct Known Subclasses
AixObject, Exec, Ldap, NameService, NetworkDevice, Package, ParsedFile
Defined Under Namespace
Classes: AixObject, Command, CommandDefiner, Exec, Ldap, NameService, NetworkDevice, Package, ParsedFile
Constant Summary collapse
Constants included from Util
Util::ALNUM, Util::ALPHA, Util::AbsolutePathPosix, Util::AbsolutePathWindows, Util::DEFAULT_POSIX_MODE, Util::DEFAULT_WINDOWS_MODE, Util::ESCAPED, Util::HEX, Util::HttpProxy, Util::PUPPET_STACK_INSERTION_FRAME, Util::RESERVED, Util::RFC_3986_URI_REGEX, Util::UNRESERVED, Util::UNSAFE
Constants included from Util::POSIX
Util::POSIX::LOCALE_ENV_VARS, Util::POSIX::USER_ENV_VARS
Constants included from Util::SymbolicFileMode
Util::SymbolicFileMode::SetGIDBit, Util::SymbolicFileMode::SetUIDBit, Util::SymbolicFileMode::StickyBit, Util::SymbolicFileMode::SymbolicMode, Util::SymbolicFileMode::SymbolicSpecialToBit
Constants included from Util::Docs
Class Attribute Summary collapse
-
.desc ⇒ Object
writeonly
Sets the documentation of this provider class.
-
.doc ⇒ String
The (full) documentation for this provider class.
-
.name ⇒ String
The name of the provider.
-
.resource_type ⇒ Puppet::Type
The resource type (that this provider is … WHAT?).
-
.source ⇒ String
Returns the data source, which is the provider name if no other source has been set.
Instance Attribute Summary collapse
-
#resource ⇒ ???
This resource is what? Is an instance of a provider attached to one particular Puppet::Resource?.
Attributes included from Util::Docs
Class Method Summary collapse
-
.command(name) ⇒ String
Returns the absolute path to the executable for the command referenced by the given name.
-
.commands(command_specs) ⇒ void
Confines this provider to be suitable only on hosts where the given commands are present.
-
.declared_feature?(name) ⇒ Boolean
Return whether the given feature has been declared or not.
-
.default? ⇒ Boolean
Returns whether this implementation satisfies all of the default requirements or not.
-
.default_match ⇒ Hash<{String => Object}>
private
Look through the array of defaultfor hashes and return the first match.
-
.defaultfor(hash) ⇒ void
Sets a facts filter that determine which of several suitable providers should be picked by default.
-
.execpipe(*args) {|pipe| ... } ⇒ String
The command can be a simple string, which is executed as-is, or an Array, which is treated as a set of command arguments to pass through.
-
.execute(*args) ⇒ Puppet::Util::Execution::ProcessOutput
Executes the desired command, and return the status and output.
-
.fact_match(fact, values) ⇒ Boolean
Compare a fact value against one or more supplied value.
- .feature_match(value) ⇒ Object
-
.has_command(name, path) {|| ... } ⇒ Object
Creates a convenience method for invocation of a command.
-
.initvars ⇒ void
Initializes defaults and commands (i.e. clears them).
-
.instances ⇒ Array<Puppet::Provider>
abstract
Returns a list of system resources (entities) this provider may/can manage.
-
.mk_resource_methods ⇒ void
Creates getter- and setter- methods for each property supported by the resource type.
- .notdefaultfor(hash) ⇒ Object
-
.optional_commands(hash) ⇒ Object
Defines optional commands.
-
.post_resource_eval ⇒ void
abstract
This method may be implemented by a provider in order to perform any cleanup actions needed.
-
.prefetch(resource_hash) ⇒ void
abstract
This method may be implemented by a provider in order to pre-fetch resource properties.
- .some_default_match(defaultlist) ⇒ Object
-
.specificity ⇒ Integer
The number of requirements is based on the hash size of the matching Provider.defaultfor.
-
.supports_parameter?(param) ⇒ Boolean
Returns true if the given attribute/parameter is supported by the provider.
Instance Method Summary collapse
-
#<=>(other) ⇒ -1, ...
Compares this provider against another provider.
-
#clear ⇒ Object
Clears this provider instance to allow GC to clean up.
-
#command(name) ⇒ String
Returns the absolute path to the executable for the command referenced by the given name.
-
#execpipe(*args, &block) ⇒ Object
Convenience methods - see class method with the same name.
-
#execute(*args) ⇒ Object
Convenience methods - see class method with the same name.
-
#flush ⇒ void
abstract
This method may be implemented by a provider in order to flush properties that has not been individually applied to the managed entity’s current state.
-
#get(param) ⇒ Object
Returns the value of a parameter value, or ‘:absent` if it is not defined.
-
#initialize(resource = nil) ⇒ Provider
constructor
Creates a new provider that is optionally initialized from a resource or a hash of properties.
-
#inspect ⇒ String
Returns a human readable string with information about the resource and the provider.
-
#name ⇒ String
Returns the name of the resource this provider is operating on.
-
#set(params) ⇒ void
Sets the given parameters values as the current values for those parameters.
-
#to_s ⇒ String
Returns a human readable string with information about the resource and the provider.
Methods included from Util::Logging
clear_deprecation_warnings, debug, deprecation_warning, format_backtrace, format_exception, get_deprecation_offender, log_and_raise, log_deprecations_to_file, log_exception, puppet_deprecation_warning, send_log, setup_facter_logging!, warn_once
Methods included from Util
absolute_path?, benchmark, chuser, clear_environment, create_erb, default_env, deterministic_rand, deterministic_rand_int, exit_on_fail, format_backtrace_array, format_puppetstack_frame, get_env, get_environment, logmethods, merge_environment, path_to_uri, pretty_backtrace, replace_file, resolve_stackframe, rfc2396_escape, safe_posix_fork, set_env, skip_external_facts, symbolizehash, thinmark, uri_encode, uri_query_encode, uri_to_path, uri_unescape, which, withenv, withumask
Methods included from Util::POSIX
#get_posix_field, #gid, groups_of, #idfield, #methodbyid, #methodbyname, #search_posix_field, #uid
Methods included from Util::SymbolicFileMode
#display_mode, #normalize_symbolic_mode, #symbolic_mode_to_int, #valid_symbolic_mode?
Methods included from Util::Docs
desc, dochook, doctable, markdown_definitionlist, markdown_header, nodoc?, pad, scrub
Methods included from Util::Warnings
clear_warnings, debug_once, maybe_log, notice_once, warnonce
Methods included from Confiner
confine, confine_collection, suitable?
Methods included from Util::Errors
#adderrorcontext, #devfail, #error_context, error_location, error_location_with_space, error_location_with_unknowns, #exceptwrap, #fail
Constructor Details
#initialize(resource = nil) ⇒ Provider
The use of a hash as a parameter needs a better explanation; why is this done? What is the intent?
Creates a new provider that is optionally initialized from a resource or a hash of properties. If no argument is specified, a new non specific provider is initialized. If a resource is given it is remembered for further operations. If a hash is used it becomes the internal ‘@property_hash` structure of the provider - this hash holds the current state property values of system entities as they are being discovered by querying or other operations (typically getters).
519 520 521 522 523 524 525 526 527 528 529 530 |
# File 'lib/puppet/provider.rb', line 519 def initialize(resource = nil) if resource.is_a?(Hash) # We don't use a duplicate here, because some providers (ParsedFile, at least) # use the hash here for later events. @property_hash = resource elsif resource @resource = resource @property_hash = {} else @property_hash = {} end end |
Class Attribute Details
.desc=(value) ⇒ Object (writeonly)
Sets the documentation of this provider class. (The full documentation is read via the doc attribute).
93 |
# File 'lib/puppet/provider.rb', line 93 attr_writer :doc |
.doc ⇒ String
The (full) documentation for this provider class. The documentation for the provider class itself should be set with the DSL method desc=. Setting the documentation with with doc= has the same effect as setting it with desc= (only the class documentation part is set). In essence this means that there is no getter for the class documentation part (since the getter returns the full documentation when there are additional contributors).
93 |
# File 'lib/puppet/provider.rb', line 93 attr_writer :doc |
.name ⇒ String
Returns The name of the provider.
58 59 60 |
# File 'lib/puppet/provider.rb', line 58 def name @name end |
.resource_type ⇒ Puppet::Type
What is this type? A reference to a Puppet::Type ?
Returns the resource type (that this provider is … WHAT?).
72 73 74 |
# File 'lib/puppet/provider.rb', line 72 def resource_type @resource_type end |
.source ⇒ String
Unclear what “the source” is used for?
Returns the data source, which is the provider name if no other source has been set.
439 440 441 |
# File 'lib/puppet/provider.rb', line 439 def self.source @source ||= name end |
Instance Attribute Details
#resource ⇒ ???
Returns This resource is what? Is an instance of a provider attached to one particular Puppet::Resource?.
98 99 100 |
# File 'lib/puppet/provider.rb', line 98 def resource @resource end |
Class Method Details
.command(name) ⇒ String
Returns the absolute path to the executable for the command referenced by the given name.
127 128 129 130 131 132 133 134 135 136 137 138 |
# File 'lib/puppet/provider.rb', line 127 def self.command(name) name = name.intern command = @commands[name] if defined?(@commands) command = superclass.command(name) if !command && superclass.respond_to?(:command) unless command raise Puppet::DevError, _("No command %{command} defined for provider %{provider}") % { command: name, provider: self.name } end which(command) end |
.commands(command_specs) ⇒ void
It is preferred if the commands are not entered with absolute paths as this allows puppet to search for them using the PATH variable.
This method returns an undefined value.
Confines this provider to be suitable only on hosts where the given commands are present. Also see Confiner#confine for other types of confinement of a provider by use of other types of predicates.
153 154 155 156 157 |
# File 'lib/puppet/provider.rb', line 153 def self.commands(command_specs) command_specs.each do |name, path| has_command(name, path) end end |
.declared_feature?(name) ⇒ Boolean
Return whether the given feature has been declared or not.
253 254 255 |
# File 'lib/puppet/provider.rb', line 253 def self.declared_feature?(name) defined?(@declared_features) and @declared_features.include?(name) end |
.default? ⇒ Boolean
Returns whether this implementation satisfies all of the default requirements or not. Returns false if there is no matching defaultfor
261 262 263 |
# File 'lib/puppet/provider.rb', line 261 def self.default? default_match ? true : false end |
.default_match ⇒ Hash<{String => Object}>
This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.
Look through the array of defaultfor hashes and return the first match.
269 270 271 272 273 |
# File 'lib/puppet/provider.rb', line 269 def self.default_match return nil if some_default_match(@notdefaults) # Blacklist means this provider cannot be a default some_default_match(@defaults) end |
.defaultfor(hash) ⇒ void
This method returns an undefined value.
Sets a facts filter that determine which of several suitable providers should be picked by default. This selection only kicks in if there is more than one suitable provider. To filter on multiple facts the given hash may contain more than one fact name/value entry. The filter picks the provider if all the fact/value entries match the current set of facts. (In case there are still more than one provider after this filtering, the first found is picked).
318 319 320 |
# File 'lib/puppet/provider.rb', line 318 def self.defaultfor(hash) @defaults << hash end |
.execpipe(*args) {|pipe| ... } ⇒ String
The command can be a simple string, which is executed as-is, or an Array, which is treated as a set of command arguments to pass through.
In either case, the command is passed directly to the shell, STDOUT and STDERR are connected together, and STDOUT will be streamed to the yielded pipe.
118 119 120 |
# File 'lib/puppet/provider.rb', line 118 def self.execpipe(*args, &block) Puppet::Util::Execution.execpipe(*args, &block) end |
.execute(*args) ⇒ Puppet::Util::Execution::ProcessOutput
Unfortunately, the default behavior for failonfail and combine (since 0.22.4 and 0.24.7, respectively) depend on whether options are specified or not. If specified, then failonfail and combine default to false (even when the options specified are neither failonfail nor combine). If no options are specified, then failonfail and combine default to true.
Executes the desired command, and return the status and output. def execute(command, options)
107 108 109 |
# File 'lib/puppet/provider.rb', line 107 def self.execute(*args) Puppet::Util::Execution.execute(*args) end |
.fact_match(fact, values) ⇒ Boolean
Compare a fact value against one or more supplied value
290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 |
# File 'lib/puppet/provider.rb', line 290 def self.fact_match(fact, values) fact_val = Puppet.runtime[:facter].value(fact).to_s.downcase if fact_val.empty? false else values = [values] unless values.is_a?(Array) values.any? do |value| if value.is_a?(Regexp) fact_val =~ value else fact_val.intern == value.to_s.downcase.intern end end end end |
.feature_match(value) ⇒ Object
306 307 308 |
# File 'lib/puppet/provider.rb', line 306 def self.feature_match(value) Puppet.features.send(value.to_s + "?") end |
.has_command(name, path) {|| ... } ⇒ Object
the name ´has_command´ looks odd in an API context, but makes more sense when seen in the internal DSL context where a Provider is declaratively defined.
Creates a convenience method for invocation of a command.
This generates a Provider method that allows easy execution of the command. The generated method may take arguments that will be passed through to the executable as the command line arguments when it is invoked.
rubocop:disable Naming/PredicateName
203 204 205 206 207 208 209 210 211 212 213 |
# File 'lib/puppet/provider.rb', line 203 def self.has_command(name, path, &block) name = name.intern command = CommandDefiner.define(name, path, self, &block) @commands[name] = command.executable # Now define the class and instance methods. create_class_and_instance_method(name) do |*args| return command.execute(*args) end end |
.initvars ⇒ void
This method returns an undefined value.
Initializes defaults and commands (i.e. clears them).
349 350 351 352 353 |
# File 'lib/puppet/provider.rb', line 349 def self.initvars @defaults = [] @notdefaults = [] @commands = {} end |
.instances ⇒ Array<Puppet::Provider>
this method must be implemented by a subclass and this super method should never be called as it raises an exception.
The returned instances are instance of some subclass of Provider, not resources.
Returns a list of system resources (entities) this provider may/can manage. This is a query mechanism that lists entities that the provider may manage on a given system. It is is directly used in query services, but is also the foundation for other services; prefetching, and purging.
As an example, a package provider lists all installed packages. (In contrast, the File provider does not list all files on the file-system as that would make execution incredibly slow). An implementation of this method should be made if it is possible to quickly (with a single system call) provide all instances.
An implementation of this method should only cache the values of properties if they are discovered as part of the process for finding existing resources. Resource properties that require additional commands (than those used to determine existence/identity) should be implemented in their respective getter method. (This is important from a performance perspective; it may be expensive to compute, as well as wasteful as all discovered resources may perhaps not be managed).
An implementation may return an empty list (naturally with the effect that it is not possible to query for manageable entities).
By implementing this method, it is possible to use the ‘resources´ resource type to specify purging of all non managed entities.
382 383 384 |
# File 'lib/puppet/provider.rb', line 382 def self.instances raise Puppet::DevError, _("To support listing resources of this type the '%{provider}' provider needs to implement an 'instances' class method returning the current set of resources. We recommend porting your module to the simpler Resource API instead: https://puppet.com/search/docs?keys=resource+api") % { provider: name } end |
.mk_resource_methods ⇒ void
This method returns an undefined value.
Creates getter- and setter- methods for each property supported by the resource type. Call this method to generate simple accessors for all properties supported by the resource type. These simple accessors lookup and sets values in the property hash. The generated methods may be overridden by more advanced implementations if something else than a straight forward getter/setter pair of methods is required. (i.e. define such overriding methods after this method has been called)
An implementor of a provider that makes use of ‘prefetch` and `flush` can use this method since it uses the internal `@property_hash` variable to store values. An implementation would then update the system state on a call to `flush` based on the current values in the `@property_hash`.
399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 |
# File 'lib/puppet/provider.rb', line 399 def self.mk_resource_methods [resource_type.validproperties, resource_type.parameters].flatten.each do |attr| attr = attr.intern next if attr == :name define_method(attr) do if @property_hash[attr].nil? :absent else @property_hash[attr] end end define_method(attr.to_s + "=") do |val| @property_hash[attr] = val end end end |
.notdefaultfor(hash) ⇒ Object
322 323 324 |
# File 'lib/puppet/provider.rb', line 322 def self.notdefaultfor(hash) @notdefaults << hash end |
.optional_commands(hash) ⇒ Object
Defines optional commands. Since Puppet 2.7.8 this is typically not needed as evaluation of provider suitability is lazy (when a resource is evaluated) and the absence of commands that will be present after other resources have been applied no longer needs to be specified as optional. (@see #has_command)
169 170 171 172 173 174 175 |
# File 'lib/puppet/provider.rb', line 169 def self.optional_commands(hash) hash.each do |name, target| has_command(name, target) do is_optional end end end |
.post_resource_eval ⇒ void
A subclass may implement this - it is not implemented in the Provider class
This method returns an undefined value.
This method may be implemented by a provider in order to perform any cleanup actions needed. It will be called at the end of the transaction if any resources in the catalog make use of the provider, regardless of whether the resources are changed or not and even if resource failures occur.
|
# File 'lib/puppet/provider.rb', line 595
|
.prefetch(resource_hash) ⇒ void
A subclass may implement this - it is not implemented in the Provider class
This method returns an undefined value.
This method may be implemented by a provider in order to pre-fetch resource properties. If implemented it should set the provider instance of the managed resources to a provider with the fetched state (i.e. what is returned from the instances method).
|
# File 'lib/puppet/provider.rb', line 585
|
.some_default_match(defaultlist) ⇒ Object
275 276 277 278 279 280 281 |
# File 'lib/puppet/provider.rb', line 275 def self.some_default_match(defaultlist) defaultlist.find do |default| default.all? do |key, values| key == :feature ? feature_match(values) : fact_match(key, values) end end end |
.specificity ⇒ Integer
Because of how this value is calculated there could be surprising side effects if a provider included an excessive amount of classes.
The number of requirements is based on the hash size of the matching defaultfor.
The ancestors is the Ruby Module::ancestors method and the number of classes returned is used to boost the score. The intent is that if two providers are equal, but one is more “derived” than the other (i.e. includes more classes), it should win because it is more specific).
336 337 338 339 340 341 342 343 344 345 |
# File 'lib/puppet/provider.rb', line 336 def self.specificity # This strange piece of logic attempts to figure out how many parent providers there # are to increase the score. What is will actually do is count all classes that Ruby Module::ancestors # returns (which can be other classes than those the parent chain) - in a way, an odd measure of the # complexity of a provider). match = default_match length = match ? match.length : 0 (length * 100) + ancestors.select { |a| a.is_a? Class }.length end |
.supports_parameter?(param) ⇒ Boolean
Returns true if the given attribute/parameter is supported by the provider. The check is made that the parameter is a valid parameter for the resource type, and then if all its required features (if any) are supported by the provider.
451 452 453 454 455 456 457 458 459 460 461 462 463 464 |
# File 'lib/puppet/provider.rb', line 451 def self.supports_parameter?(param) if param.is_a?(Class) klass = param else klass = resource_type.attrclass(param) unless klass raise Puppet::DevError, _("'%{parameter_name}' is not a valid parameter for %{resource_type}") % { parameter_name: param, resource_type: resource_type.name } end end features = klass.required_features return true unless features !!satisfies?(*features) end |
Instance Method Details
#<=>(other) ⇒ -1, ...
Compares this provider against another provider. Comparison is only possible with another provider (no other class). The ordering is based on the class name of the two providers.
577 578 579 580 581 582 583 |
# File 'lib/puppet/provider.rb', line 577 def <=>(other) # We can only have ordering against other providers. return nil unless other.is_a? Puppet::Provider # Otherwise, order by the providers class name. self.class.name <=> other.class.name end |
#clear ⇒ Object
Clears this provider instance to allow GC to clean up.
493 494 495 |
# File 'lib/puppet/provider.rb', line 493 def clear @resource = nil end |
#command(name) ⇒ String
Returns the absolute path to the executable for the command referenced by the given name.
498 499 500 |
# File 'lib/puppet/provider.rb', line 498 def command(name) self.class.command(name) end |
#execpipe(*args, &block) ⇒ Object
Convenience methods - see class method with the same name.
113 114 115 |
# File 'lib/puppet/provider.rb', line 113 def execpipe(*args, &block) Puppet::Util::Execution.execpipe(*args, &block) end |
#execute(*args) ⇒ Object
Convenience methods - see class method with the same name.
102 103 104 |
# File 'lib/puppet/provider.rb', line 102 def execute(*args) Puppet::Util::Execution.execute(*args) end |
#flush ⇒ void
A subclass may implement this - it is not implemented in the Provider class
This method returns an undefined value.
This method may be implemented by a provider in order to flush properties that has not been individually applied to the managed entity’s current state.
|
# File 'lib/puppet/provider.rb', line 606
|
#get(param) ⇒ Object
Returns the value of a parameter value, or ‘:absent` if it is not defined.
506 507 508 |
# File 'lib/puppet/provider.rb', line 506 def get(param) @property_hash[param.intern] || :absent end |
#inspect ⇒ String
Returns a human readable string with information about the resource and the provider.
564 565 566 |
# File 'lib/puppet/provider.rb', line 564 def inspect to_s end |
#name ⇒ String
Returns the name of the resource this provider is operating on.
536 537 538 539 540 541 542 543 544 545 |
# File 'lib/puppet/provider.rb', line 536 def name n = @property_hash[:name] if n n elsif resource resource.name else raise Puppet::DevError, _("No resource and no name in property hash in %{class_name} instance") % { class_name: self.class.name } end end |
#set(params) ⇒ void
This method returns an undefined value.
Sets the given parameters values as the current values for those parameters. Other parameters are unchanged.
552 553 554 555 556 |
# File 'lib/puppet/provider.rb', line 552 def set(params) params.each do |param, value| @property_hash[param.intern] = value end end |
#to_s ⇒ String
Returns a human readable string with information about the resource and the provider.
559 560 561 |
# File 'lib/puppet/provider.rb', line 559 def to_s "#{@resource}(provider=#{self.class.name})" end |