Requester::Requester Class Reference

Requesters are responsible for providing the data requested via a "get" statement in tests.cfg (Monitor::Tester). More...

Inheritance diagram for Requester::Requester:

List of all members.

Public Class Methods
	new ()
	create a requester.
Public Object Methods
void	register (list domains)
	Register a requester for one or multiple domains.
hashref	request (hashref env, scalar domain, arrayref variables)
	Computes (or requests) the values of the variables listed in variables.
boolean	fail_novar (boolean fail)
	Not used any more?
hashref	getinfo (arrayref gets, arrayref indexes)
	Called by the default request() method with gets set to the list of the variables, indexes set to the list of variable indexes to be retrieved.
hashref	getwalk (arrayref gets, arrayref indexes, arrayref walks)
	Similiar to getinfo(), but getwalk() is called by the default request() method if the request includes a "walk" and passes the list of variables to be walked via the walks parameter.
boolean	available (hashref env)
	Determine if a requester is willing to perform (handle requests) for a given tester environment.
boolean	command_available (list cmd)
	Tests if cmd is runnable - usually called by classes inherited from Requester::Requester in their available() method in order to find out if a system command they require is present or not.
int	criticalness (int criticalness)
	Get/Set the criticalness of a handler.
int	consumes (int consumes)
	Get/set consume level of a handler.
Public Functions
list	probe_consumes (hashref env, arrayref variables)
	Given a list of variable names and an environment, probe_consumes() will try to determine the criticalness/consumes values for the requests that it takes to get all those variable's values.
hashref	get (hashref env, arrayref variables)
	Given a list of variable names and a tester environment requests all the variables and returns the result in a hash ref.
Requester::Requester	get_handler (scalar domain)
	Given the name of a domain this function searches for a request handler that is willing to perform requests for this domain.
boolean	load_module (scalar module)
	Given the name of a module tries to dynamically load Requester::modulename.
Protected Functions
protected void	preexit ()
	This function is called during program shutdown.
protected hashref	_get (hashref env, arrayref variables, scalar probe_only)
	Implements both the get() and probe_consumes() call.
protected void	set_cache (hashref env, scalar domain, scalar name, hashref value)
	Given a domain, variable name and a value stores the value in the cache under the given domain/name.
protected void	clear_cache ()
	Clear the variable cache.

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Detailed Description

Requesters are responsible for providing the data requested via a "get" statement in tests.cfg (Monitor::Tester).

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Member Function Documentation

protected hashref Requester::Requester::_get (  hashref  env, arrayref  variables, scalar  probe_only )

Implements both the get() and probe_consumes() call. Parameters: env  Tester environment variables  List of variable names probe_only  If set use probe_consumes() semantics, otherwise get() is performed Returns: Hashref compatible with get() if called with probe_only not set, otherwise a hashref with the keys being the names of domains that need a requester to be called.

boolean Requester::Requester::available (  hashref  env  )

Determine if a requester is willing to perform (handle requests) for a given tester environment. Usually, available() will return false if some required system command is not installed, some API is missing, the test works only against a local machine but the target host is not the local machine, etc. Parameters: env  Tester environment Returns: true if requester is willing to handle requests, false otherwise

protected void Requester::Requester::clear_cache (   )

Clear the variable cache.

boolean Requester::Requester::command_available (  list  cmd  )

Tests if cmd is runnable - usually called by classes inherited from Requester::Requester in their available() method in order to find out if a system command they require is present or not. Note: The command in question is actually executed via system(), so it is required that the cmd argument includes "save" command line options ensuring that no harm is done to the system and Big Sister. Parameters: cmd  The command to be tested for availability.

int Requester::Requester::consumes (  int  consumes  )

Get/set consume level of a handler. The higher the "consumes" figure is the more other handlers will suffer if running in parallel with this handler. Parameters: consumes  (optional) if defined, set the consumes figure to this value Returns: The current 'consumes' figure.

int Requester::Requester::criticalness (  int  criticalness  )

Get/Set the criticalness of a handler. The higher the criticalness the more the handler will suffer from other handlers to be running in parallel. Parameters: criticalness  (optional) If defined, set the criticalness to this value Returns: The level of criticalness.

boolean Requester::Requester::fail_novar (  boolean  fail  )

Not used any more? Todo: check if fail_novar() is still in use by someone, and if yes, what the hell it is used for

hashref Requester::Requester::get (  hashref  env, arrayref  variables )

Given a list of variable names and a tester environment requests all the variables and returns the result in a hash ref. Parameters: env  Tester environment variables  A list of variable names. Returns: A hash ref.

Requester::Requester Requester::Requester::get_handler (  scalar  domain  )

Given the name of a domain this function searches for a request handler that is willing to perform requests for this domain. If no handler has been registered yet, it tries to dynamically load one via load_module(). Parameters: domain  The name of the domain Returns: The handler of the domain or undef if none was found.

hashref Requester::Requester::getinfo (  arrayref  gets, arrayref  indexes )

Called by the default request() method with gets set to the list of the variables, indexes set to the list of variable indexes to be retrieved. If gets or indexes are undefined, this means that a 'walk' through all the possible variables has to be performed. The default behaviour is to call the getwalk() method with an empty walks list. So, a requester implementation has to implement at least one of request(), getinfo() or getwalk() in order to do something useful. Parameters: gets  The list of names of the variables that have to be retrieved. indexes  The list of variable indexes that have to be retrieved. Returns: A folded hashref, at the first level the hashref uses the variable index as key, the values each point to a hashref with the name of the respective variable as a key, the scalar value as the value. Reimplemented in Requester::expedap, and Requester::SlowRequester.

hashref Requester::Requester::getwalk (  arrayref  gets, arrayref  indexes, arrayref  walks )

Similiar to getinfo(), but getwalk() is called by the default request() method if the request includes a "walk" and passes the list of variables to be walked via the walks parameter. The default behaviour of getwalk() is to just call getinfo() with gets/indexes unset. This has been the default behaviour before getwalk() has been introduced, so getwalk() behaves the same in order to avoid breaking existing requesters. A requester implementation has to implement at least one of request(), getinfo() or getwalk() in order to do something useful. Parameters: gets  The list of names of the variables that have to be retrieved. indexes  The list of variable indexes that have to be retrieved. walks  The list of variables that have to be "walked" Returns: A folded hashref, at the first level the hashref uses the variable index as key, the values each point to a hashref with the name of the respective variable as a key, the scalar value as the value. Reimplemented in Requester::expedap.

boolean Requester::Requester::load_module (  scalar  module  )

Given the name of a module tries to dynamically load Requester::modulename. Parameters: module  The name of a module Returns: true if successful, false otherwise

Requester::Requester::new (   )

create a requester. Reimplemented in Requester::expedap.

protected void Requester::Requester::preexit (   )

This function is called during program shutdown.

list Requester::Requester::probe_consumes (  hashref  env, arrayref  variables )

Given a list of variable names and an environment, probe_consumes() will try to determine the criticalness/consumes values for the requests that it takes to get all those variable's values. Parameters: env  Tester environment variables  A list of variable names. Returns: An array with two values: The first one being the criticalness, the 2nd one the consumer level of the most critical or most consuming requester that has to be called. Returns undef if no requester has to be called at all.

void Requester::Requester::register (  list  domains  )

Register a requester for one or multiple domains. Each Requester has to register itself under a unique domain name. Typically, a requester will create an instance of itself on load (a singleton) and register this instance via register(). This instance will then get "get" requests for the registered domains. Parameters: domains  The list of domain names to register.

hashref Requester::Requester::request (  hashref  env, scalar  domain, arrayref  variables )

Computes (or requests) the values of the variables listed in variables. The default request() method will process the list of variables and then call getwalk() if the request includes a walk, getinfo() otherwise. Parameters: env  Tester environment domain  The name of the domain the request is associated with. If the requester in question is registered for one single domain only, this is always the name of the registered domain. variables  List of variable names that are requested. Variable names starting with '@' mean that the requester is supposed to return all variables/values below this prefix. Returns: A hashref containing the variable names associated with their values. Returns 'undef' if the requester cannot perform the request (i.e. because the variable names are unknown or the underlying system failed)

protected void Requester::Requester::set_cache (  hashref  env, scalar  domain, scalar  name, hashref  value )

Given a domain, variable name and a value stores the value in the cache under the given domain/name. Parameters: env  Tester environment domain  Domain name name  Variable name value  Value associated with domain/name. The values being stored in the cache are required to be hash references.

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The documentation for this class was generated from the following file:

• uxmon/Requester/Requester.pm

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