Set a "default" mount_point

[johnnybubonic]

When one is using an instance of hvac.Client primarily with multiple operations on a single/specific mountpoint, it can become verbose/tedious to specify this same mount_point multiple times. (Think multiple operations of listing and updating secrets across multiple paths within the same mount, for instance.)

Would it be a lot of work to have an attribute on the instance that specifies the default mount_point? The way I see this potentially being the most user-friendly and realistic is being able to instantiate an appropriate hvac.api.VaultApiBase subclass (such as hvac.api.secrets_engines.kv_v2.KvV2) with a __init__(self, mount_point = None). If mount_point is None, it'd use the DEFAULT_MOUNT_POINT value in each respective subclass (with 'mount_point' in each method still being able to override this and falling back to the class' attribute instead of the file-global DEFAULT_MOUNT_POINT).

Thoughts? Am I describing this clearly? I feel like I'm not, heh.

[jeffwecan]

Yeah that makes plenty of sense and I imagine wouldn't be too terribly difficult to implement. 👍🏻

[iMisteg]

There is no ready-made solution yet, can someone tell me how the functionality of setting the default value can be implemented on the current version of the code? I tried like this

from hvac.api.secrets_engines.kv_v2 import KvV2
KvV2.DEFAULT_MOUNT_POINT = 'kv'

But it doesn't work

[johnnybubonic]

@iMisteg This is why that won't work: https://docs.python-guide.org/writing/gotchas/#mutable-default-arguments

Namely, when the module (or submodule, in this case - the class, specifically) is imported, the method's definition is read in and held in memory. This includes whatever the value is of the method's parameters' defaults.

In other words, as soon as you import KvV2, it reads the method definitions and, in the process of parsing those definitions, it reads whatever DEFAULT_MOUNT_POINT is at that time. In KvV2's instance, this is secret. It does not matter if you change DEFAULT_MOUNT_POINT after importing, as it's already been resolved to a static value on import.

@jeffwecan There are two ways to fix this. Either you can make the default mount point an instance's attribute:

DEFAULT_MOUNT_POINT = 'secret'

# ...

class Foo(object):
    def __init__(self, mount_point = DEFAULT_MOUNT_POINT):
        self.mount_point = mount_point
# ...
    def bar(self):
        do_something_here(self.mount_point)

and Foo() would then need to be instantiated (baz = Foo(mount_point = 'something_else')).

OR

You can implement it on each method like so:

DEFAULT_MOUNT_POINT = 'secret'

# ...

class Foo(object):
    def __init__(self):
# ...
    def bar(self, mount_point = None):
        if not mount_point:
            mount_point = DEFAULT_MOUNT_POINT
        do_something_here(mount_point)

But it MUST be None for this to work (as I mentioned in my initial comment).

EDIT:

You can, of course, hybridize the two as well:

DEFAULT_MOUNT_POINT = 'secret'

# ...

class Foo(object):
    def __init__(self, mount_point = DEFAULT_MOUNT_POINT):
        self.mount_point = mount_point
# ...
    def bar(self, mount_point = None):
        if not mount_point:
            mount_point = self.mount_point
        do_something_here(mount_point)

This would provide the maximum flexibility, but is quite a bit extraneous.

[johnnybubonic]

(The second (None default per-method) or third (hybrid) designs above would retain backwards compatibility.)

[eytanhanig]

Any progress on this? It's a real quality of life improvement.

[Stogas]

Agree, this is a very useful enhancement.

[mddataminr]

Paying customer here - This would be great to have!