H3C switches are too slow in executing commands

[LeisureZhao]

Compared to Cisco switches, H3C switches are too slow in executing
commands because the value of the pattern is not set in the
check_config_mode function. This function is called twice in both
the config_mode and exit_config_mode, each time using read_channel_timing
instead of read_until_pattern, which greatly extends the duration.
This commit set default pattern of hp_comware to save time when
checking the config mode.

[ktbyers]

@LeisureZhao What would be the value of explicit_pattern here?

[LeisureZhao]

@LeisureZhao What would be the value of explicit_pattern here?

I tried to set explicit_pattern to r"[>]|]", which means that when a pattern with > or ] appears, the read will stop. The configuration example is as follows:

switch_config = {
'device_type': 'hp_comware',
'host': xxx,
'username': xxx,
'password': xxx,
'explicit_pattern': r"[>]|]"
}

Considering the need to be compatible with past usage habits, the code logic remains unchanged when the explicit_pattern is not set. If it is deemed that the execution time of the command is too long, you can set the explicit_pattern configuration item for hp_comware. The pattern can be customized according to the actual switch.

[ktbyers]

@LeisureZhao I think we should implement this as a defined pattern on check_config_mode and not as an argument that we pass in via __init__.py.

Does that sound reasonable.

Can you restructure the PR to implement that?

[LeisureZhao]

@LeisureZhao I think we should implement this as a defined pattern on check_config_mode and not as an argument that we pass in via __init__.py.

Does that sound reasonable.

Can you restructure the PR to implement that?

Completed modifications, please review.

[ktbyers]

@LeisureZhao Why the | (pipe character) here?

[ktbyers]

Superseded by #3573