GwCmdValidatorsPattern

The GwCmdValidatorsPattern can be used to valid the execution of a command.

This can helpful to verify the version of an installed tool by checking, if the output contains the correct version.

For some cases also the correct behavior can be validated by checking the correct return value or by setting a limit for the maximum allowed execution time.

Validating the output of a command

All different types of command validations are available by using the function validate():

import sys
from groundwork_validation.patterns import GwCmdValidatorsPattern

class My_Plugin(GwCmdValidatorsPattern):
      def __init__(self, app, **kwargs):
          self.name = "My_Plugin"
          super(My_Plugin, self).__init__(app, **kwargs)

      def activate(self):
          if self.validators.cmd.validate("dir", search="my_folder"):
              print("Command 'dir' works as expected.")
          else:
              print("Command 'dir' seems not to work correctly. We stop here")
              sys.exit(1)

      def deactivate(self):
          pass

Instead of searching for a specific string, you can also use a regular expression:

# Checks for an e-mail address
if self.validators.cmd.validate("dir",
                                regex="(^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$)"):
    print("Found at least one e-mail address")

Validating the return code

By validating the return code, you can easily check if the command is available and exits like expected. If the return code is not allowed, the exception NotAllowedReturnCode is raised:

import sys
from groundwork_validation.patterns import GwCmdValidatorsPattern
from groundwork_validation.patterns.gw_cmd_validators_pattern.gw_cmd_validators_pattern import NotAllowedReturnCode

 class My_Plugin(GwCmdValidatorsPattern):
        def __init__(self, app, **kwargs):
            self.name = "My_Plugin"
            super(My_Plugin, self).__init__(app, **kwargs)

        def activate(self):
            try:
                if self.validators.cmd.validate("dir", search="my_folder", allowed_return_codes=[0, 1]):
                    print("Command 'dir' works a expected.")
                else:
                    print("Command 'dir' seems not to work correctly. We stop here")
                    sys.exit(1)
            except NotAllowedReturnCode:
                print("Command exists with not allowed status code. Validation failed!")
                sys.exit(1)

Setting a timeout

By default the command is killed after a timeout of 2 seconds and CommandTimeoutExpired is raised. You are free to set your own timeout for each validation:

import sys
from groundwork_validation.patterns import GwCmdValidatorsPattern
from groundwork_validation.patterns.gw_cmd_validators_pattern.gw_cmd_validators_pattern \
    import NotAllowedReturnCode, CommandTimeoutExpired

class My_Plugin(GwCmdValidatorsPattern):
        def __init__(self, app, **kwargs):
            self.name = "My_Plugin"
            super(My_Plugin, self).__init__(app, **kwargs)

        def activate(self):
            try:
                if self.validators.cmd.validate("dir", search="my_folder", timeout=5):
                    print("Command 'dir' works a expected.")
                else:
                    print("Command 'dir' seems not to work correctly. We stop here")
                    sys.exit(1)
            except CommandTimeoutExpired:
                print("Command has not finished and raised a timeout. This is not expected. We stop here!")
                sys.exit(1)

test:

pip install

Requirements & Specifications

The following sections describes the implemented requirements and their related specifications.

Available requirements

ID	Title	Type	Status	Links	Tags
R_79027	Command output validation	Requirement			gwcmdvalidators
R_77A07	Command runtime validation	Requirement			gwcmdvalidators
R_72AC6	Command exit code validation	Requirement			gwcmdvalidators

Available specifications

ID	Title	Type	Status	Links	Tags
S_102F8	command output check	Specification		R_79027	gwcmdvalidators
S_EB190	command exit code check	Specification		R_72AC6	gwcmdvalidators
S_8C1D8	command timeout check	Specification		R_77A07	gwcmdvalidators
S_2C5EC	Command execution	Specification		R_79027; R_72AC6; R_77A07	gwcmdvalidators

Requirements

Requirement: Command output validation (R_79027)

As developer I want to be able to validate the correct output of an executed command.

tags: gwcmdvalidators

Requirement: Command exit code validation (R_72AC6)

As developer I want to be able to validate the correct exit code of an executed command

tags: gwcmdvalidators

Requirement: Command runtime validation (R_77A07)

As developer I want to be able to validate the maximum needed run time of an executed command

tags: gwcmdvalidators

Specifications

Specification: Command execution (S_2C5EC)

With self.validators.cmd.validate the developer is able to execute a command on command line. This execution takes place in a subprocess, but the application must wait till it ends.

The first argument must be the command to execute

tags: gwcmdvalidators

links: R_79027 ; R_72AC6 ; R_77A07

Specification: command output check (S_102F8)

As keyword argument “search” of self.validators.cmd.validate the output on STDOUT is checked, if the given string is part of it.

If yes, True is returned. Otherwise False

tags: gwcmdvalidators

links: R_79027

Specification: command exit code check (S_EB190)

As keyword argument “allowed_return_codes” of self.validators.cmd.validate as list of allowed return codes can be defined.

If the retrieved return code is not in this list, the Error NotAllowedReturnCode is raised.

tags: gwcmdvalidators

links: R_72AC6

Specification: command timeout check (S_8C1D8)

As keyword argument “timeout” of self.validators.cmd.validate a time in seconds can be set.

If the execution of the given command takes longer as specified, the execution is aborted and the error CommandTimeoutExpired is raised.

tags: gwcmdvalidators

links: R_77A07