Placet documentation

Communicator(process_name, **kwargs)

Bases: ABC

A class used to interact with the process spawned with Pexpect.

Attributes:

Name	Type	Description
process	pexpect.spawn	The child process spawned with pexpect.
debug_mode	bool	If True, running in debug mode.

Parameters:

Name	Type	Description	Default
process_name	str	Name of the child process	required

Other Parameters:

Name	Type	Description
debug_mode	bool	If True (default is False), runs Communicator in debug mode.
save_logs	bool	If True (default is True) , invoking save_debug_info().
send_delay	float	The time delay before each data transfer to a child process (sometimes needed for stability). Default is Communicator._BUFFER_MAXSIZE.

__save_logs()

Open the files to store the log data of a child process

By default, the names are "log_send.txt" for logfile_send and "log_read.txt" for logfile_read.

__terminate()

Terminate the child process.

add_send_delay(time=_DELAY_BEFORE_SEND)

Add the time delay before each data transfer.

Parameters:

Name	Type	Description	Default
time	float	The time delay.	_DELAY_BEFORE_SEND

close()

Close all the associated threads running.

flush()

Flush the child process buffer

readline() abstractmethod

Read the line from the child process.

Returns:

Type	Description
str	The line of the data received from the child process.

readlines(N_lines, timeout=_BASE_TIMEOUT)

Read several lines from the child process.

Parameters:

Name	Type	Description	Default
N_lines	int	Number of lines to read.	required
timeout	float	Timeout of the reader before raising the exception. [30.11.2022] - No effect anymore. The parameter is kept for compatibility.	_BASE_TIMEOUT

Returns:

Type	Description
list	The list of the lines received from the child process.

save_debug_info(filename='debug_data.pkl')

Save the debug info to a files.

Parameters:

Name	Type	Description	Default
filename	str	Name of the file.	'debug_data.pkl'

skipline(timeout=_BASE_TIMEOUT)

Skip the line of the child's process output.

Parameters:

Name	Type	Description	Default
timeout	float	Timeout of the reader before raising the exception. [30.11.2022] - No effect anymore. The parameter is kept for compatibility.	_BASE_TIMEOUT

writeline(command, skipline=True, timeout=_BASE_TIMEOUT, **kwargs)

Send the line to a child process.

There is an expect call to search for a prompt defined in Communicator._TERMINAL_SPECIAL_SYMBOL (default value is '% ') before writing to a process - process.write(). Doing so, we make sure that we do not try to write while the process is still busy with the previous command. We set the default timeout of Communicator._BASE_TIMEOUT.

The optional parameters expect_before and expect_after used to specify when to use the expect command in between writing the command. There has to be always 1 expect call after command execution. By default, one expect call is used before writing the command. In certain situations, one would want to do the expect call after the command is written. The parameter __expect_block controls the use of expect commands - making sure, only 1 expect command is executed in between 2 commands.

Parameters:

Name	Type	Description	Default
command	str	Command to execute	required
skipline	bool	If True, reads the command that was sent to a child process from child's process output This flag depends on the default running mode of pexpect. By default, it outputs to stdout what was just send to stdin	True
timeout	float	Timeout of the reader before raising the exception. [30.11.2022] - No effect anymore. The parameter is kept for compatibility.	_BASE_TIMEOUT

Other Parameters:

Name	Type	Description
expect_before	bool	If True (default is True), expect is invoked before writing the command.
expect_after	bool	If True (default is False), expect is invoked after writing the command.
no_expect	bool	If True (default is False), no expect is invoked, ignoring __expect_block

Returns:

Type	Description
str	The command that was sent to a child process