hvac not support http2

[LuckySB]

I create AWL load balancer before my vault instance
in target group definition i set Protocol version: HTTP2

Connect to vault failed with message

None, on get https://vault.internal.com/v1/auth/token/lookup-self

i add some debug to module, and found that AWS ALB return me code 464

so:
https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-troubleshooting.html

HTTP 464
The load balancer received an incoming request protocol that is incompatible with the version config of the target group protocol.
Possible causes:
The request protocol is an HTTP/1.1, while the target group protocol version is a gRPC or HTTP/2.

1. raise_for_error should show status_code in error message when call UnexpectedError
2. hvac should try to use HTTP2 as modern browser or curl

my workaround - recreate aws target group with protocol HTTP1.1

[colin-pm]

hvac uses requests to interact with Vaults API, which to my knowledge does not support HTTP/2. I'm not sure if that is on the requests maintainers backlog or not. Adding support will likely require having to migrate from requests to a new python module that supports HTTP/2, like httpx or hyper.

[briantist]

Right now I think we're too entrenched with requests to support an alternate backend in the library, and our adapter system looks like it could be used in this way on the surface, but there are a few too many things that make assumptions about requests at this time.

hyper seems to no longer be maintained.

httpx claims to be broadly compatible with requests:

• https://www.python-httpx.org/compatibility/

Since you are able to provide a custom requests.Session with hvac (example), you could try your hand at passing an instance of httpx.Client instead. I haven't tested it though.

[Ousret]

Hello there,

Sorry to barge in,
There's an alternative you may be interested in. https://github.com/jawah/niquests

This is a drop-in-worthy replacement for Requests that ships with modern capabilities and allows you a painless transition.
I can answer any concerns you may have.

[briantist]

Thanks @Ousret , not barging in at all, appreciate the recommendation!

If you'd like to show some working examples of using hvac with niquests, we would consider accepting a PR to feature those examples in https://github.com/hvac/hvac/blob/main/docs/advanced_usage.rst

Since niquests seems to be broadly requests compatible, it could probably work two different ways with hvac:

1. Pass a session to the hvac.Client
2. Create a custom Adapter similar to the RawAdapter that uses niquests instead of requests (it would either need to combine the features of JSONAdapter or provide a second custom JSON-based adapter that inherits from the custom Raw Adapter)