Unable to implement an extractor the references my app-specific server context

[inickles]

I was looking to implement an ExclusiveExtractor that references data in my server context, and at first glance I thought I was going to be able to, but now I'm not seeing how I can specify my concrete type to be able to do so.
I want to do something like:

#[async_trait]
impl<T> ExclusiveExtractor for VerifiedGithubBody<T>
where
    T: Sync + Send,
{
    async fn from_request(
        rqctx: &RequestContext<MyContext>,
        request: hyper::Request<hyper::Body>,
    ) -> Result<Self, HttpError> {
        let context = rqctx.context();
        let hmac_secret = context.github_hmac_secret;

        ...
    }
...
}

where MyContext is:

pub(crate) struct MyContext{
    pub(crate) github_hmac_secret: secrecy::SecretString,
}

but that doesn't work.

I can do all the work of this in the endpoint handler, which is fine, but it would be my preference to do this kind of thing in an extractor. Alternatively, I could pass that access that data via other means, such as environment variables, but it is also my preference to not use that for secrets. The server context seems like an appropriate place to store that.

[jclulow]

Have you see what @augustuswm did in https://github.com/oxidecomputer/dropshot-verified-body/blob/main/src/services/github.rs ?

[inickles]

Have you see what @augustuswm did in https://github.com/oxidecomputer/dropshot-verified-body/blob/main/src/services/github.rs ?

I did, yeah, that's kind of how I got here. I noticed it was getting the key from env (https://github.com/oxidecomputer/dropshot-verified-body/blob/main/src/services/github.rs#L40) and him and I were discussing how we'd like for that to come from the context instead, so I thought I'd work up a PR for it. But then I got stuck here.