factories – The factory functions

Factory functions

A number of tests have a lot of machinery in common, so here we provide some factory functions to avoid repetitions and bugs.

Examples

>>> # create a driver with a custom function
>>> def foo(vcheck, fname, lpath):
...     msg = "doing something on {} for the driver {}"
...     print(msg.format(fname[lpath:], vcheck))
>>> a_function_driver = function_factory(foo)

>>> # create a driver with a command line call
>>> cmd = "ls -lh"
>>> ls_driver = command_line_factory(cmd)
>>> # also a list is accepted
>>> cmd = ["ls", "-lh"]
>>> ls_driver = command_line_factory(cmd)
>>> # if you want to use a cure tool, the command must be:
>>> cmd = "checkheader -E -r {recipe}"
>>> cure_driver = command_line_factory(cmd)

>>> # create a driver with a function returning the command line
>>> def cmd_func(vcheck, fname, log, conf):
...     cmd = "ls -lh"
...     return cmd
>>> ls_driver = command_func_factory(cmd_func)

libvhc.factories.FILES_IFU = 4

number of files per ifu

class libvhc.factories.function_factory(func, files_IFU=4, n_exp_option='n_exposures')

Bases: object

Gives the number of expected files per IFU to the html interface, loops through the files for the recipe at hand, and call func.

Parameters:

func : callable

function to execute:

func(vcheck, fname, lpath)

vcheck : instance of VCheck
	store the recipe name and the check currently executing
fname : string
	name of the file to check
lpath : int
	lenght of the path in fname to remove for the html interface

files_IFU : int

expected files per IFU. Should always be 4.

n_exp_option : string

name of the option containing the number of exposures. This option must be present in the section of the recipe at hand.

Returns:

driver : callable

implementation of the driver. For the signature see function_signature(); args and kwargs are not implemented here.

__call__(self, vcheck, path, argv)

Execute the driver

Parameters:

vcheck : instance of VCheck

store the recipe name and the check currently executing

path: string

path provided to the vhc executable.

argv: list of strings

remaining of the command line

class libvhc.factories.command_func_factory(cmd_func, files_IFU=4, n_exp_option='n_exposures')

Bases: libvhc.factories.function_factory

Gives the number of expected files per IFU to the html interface, loop through the files for the recipe at hand, and call a function that execute the shell command returned by cmd_func on each file, log the stdout and stderr appropriately and inform the html renderer about the test.

The factory can expands the following variables in the output of cmd_func:

recipe	recipe at hand
driver	driver at hand
ifuslot	id of the slot from fname
ifuid	id of the ifu corresponding to the above
fname	name of the file to test
headkey	instruct cure to write in the fits headers the version of VHC and whether the check is successful or not
json	instruct cure to write json ouput of the to STDOUT, this is then parsed by the loggers

The substitution syntax follow the new string format; e.g. checkheader {fname} expands the fname to the value passed to the function.

Parameters:

cmd_func : callable

function returning the string of the shell call:

cmd_func(vcheck, fname, log, conf) -> cmd

Parameters:
	vcheck : instance of VCheck
		store the recipe name and the check currently executing
	fname : string
		name of the file to check
	log : instance of logging.LoggerAdapter
		logger
	conf : instance of configparser.ConfigParser
		configuration object
Returns:
	cmd : string
		string of the command to execute

files_IFU : int

expected files per IFU. Should always be 4.

n_exp_option : string

name of the option containing the number of exposures. This option must be present in the section of the recipe at hand.

Returns:

driver : callable

implementation of the driver. For the signature see function_signature(); args and kwargs are not implemented here.

__call__(self, vcheck, path, argv)

Execute the driver

Parameters:

vcheck : instance of VCheck

store the recipe name and the check currently executing

path: string

path provided to the vhc executable.

argv: list of strings

remaining of the command line

file_driver(self, vcheck, fname, lpath)

Run the given check on every file

Parameters:

vcheck : instance of VCheck

store the recipe name and the check currently executing

fname : string

name of the file

lpath : int

lenght of the path in fname to remove for the html interface

class libvhc.factories.command_line_factory(cmd, files_IFU=4, n_exp_option='n_exposures')

Bases: libvhc.factories.command_func_factory

Gives the number of expected files per IFU to the html interface, loop through the files for the recipe at hand, and call a function that execute the shell command cmd on each file, log the stdout and stderr appropriately and inform the html renderer about the test.

The factory allows to expand the variables described in command_func_factory

Parameters:

cmd : string or list of string

command to execute

files_IFU : int

expected files per IFU. Should always be 4.

n_exp_option : string

name of the option containing the number of exposures. This option must be present in the section of the recipe at hand.

Returns:

driver : callable

implementation of the driver. For the signature see function_signature(); args and kwargs are not implemented here.

cmd_(self, *_)

Function that ignores all input and return cmd

libvhc.factories._pickle_method(m)

In python 2 it’s not possible to pickle instance methods directly. This function does some magic to do it.

Only for python 2 is this function registers to allow methods pickling

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