The northbound infrastructure for operational data was subpar compared
to the infrastructure for configuration data. This commit addresses most
of the existing problems, making it possible to write operational-data
callbacks for more complex YANG models.
Summary of the changes:
* Add support for nested YANG lists.
* Add support for leaf-lists.
* Add support for leafs of type "empty".
* Introduce the "show yang operational-data XPATH" command, and write an
unit test for it. The main purpose of this command is to make it
easier to test the operational-data northbound callbacks.
* Introduce the nb_oper_data_iterate() function, that can be used
to iterate over operational data. Make the CLI and sysrepo use this
function.
* Since ConfD has a very peculiar API, it can't reuse the
nb_oper_data_iterate() like the other northbound clients. In this
case, adapt the existing ConfD callbacks to support the new features
(and make some performance improvements in the process).
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
A while ago all FRR configuration commands were converted to use the
QOBJ infrastructure to keep track of configuration objects. This
means the configuration lock isn't necessary anymore because the
QOBJ code detects when someones tries to edit a configuration object
that was deleted and react accordingly (log an error and abort the
command). The possibility of accessing dangling pointers doesn't
exist anymore since vty->index was removed.
Summary of the changes:
* remove the configuration lock and the vty_config_lockless() function.
* rename vty_config_unlock() to vty_config_exit() since we need to
clean up a few things when exiting from the configuration mode.
* rename vty_config_lock() to vty_config_enter() to remove code
duplication that existed between the three different "configuration"
commands (terminal, private and exclusive).
Configuration commands converted to the new northbound model don't
need the configuration lock either since the northbound API also
detects when someone tries to edit a configuration object that
doesn't exist anymore.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
When editing the candidate configuration, the northbound must ensure
that either all changes made by a command are accepted or none are.
This is done to prevent inconsistent states where only parts of a
command are applied in the event any error happens.
The previous API for converted commands, the nb_cli_cfg_change()
function, required callers to pass an array containing all changes
that needed to be applied in the candidate configuration. The
problem with this API is that it was very inconvenient for complex
commands, which change different configuration options depending
on several factors. This required users to manipulate the array
of configuration changes using low-level primitives, making it
complicated to implement some commands.
To solve this problem, introduce a new API based on the two following
functions:
- nb_cli_enqueue_change()
- nb_cli_apply_changes()
The first function is used to enqueue configuration changes, one
at time. Then the nb_cli_apply_changes() function is used to apply
all the enqueued configuration changes.
To implement this, a static-sized array was allocated in the "vty"
structure, along with a counter of enqueued changes. This eliminates
the need to declare an array of configuration changes in every
converted CLI command, simplifying things quite considerably.
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
