Refactoring of https connector to make root certificates optional

[pawelchcki]

Root certificates can be missing on the machine/container this library runs in. Currently the existing hyper_rusttls implementation with panic, and exit.

One way to avoid this is to rewrite part of the client initialization code to make it fail gracefully. Started this PR to see how that could look, but don't have time this week to bring this past the finish line

[r1viollet]

very cool having this cfg right inside the enum

[paullegranddc]

Oh nice, I thought pin_project_lite didn't understand cfg macros

[pawelchcki]

Sorry for confusion, The cfg macro got silently ignored by the pin_project_lite.

I've added windows builds to catch these in the future

[r1viollet]

Thanks !
LGTM. Another set of eyes would be nice to check on lifetimes and ownership (topic on which I'm not relevant enough).

[paullegranddc]

Oh nice, I thought pin_project_lite didn't understand cfg macros

[pawelchcki]

#47 (comment)

TBF I'm not certain it works as expected, I'll try quickly adding a Windows build 🤞

[r1viollet]

#47 (comment)

TBF I'm not certain it works as expected, I'll try quickly adding a Windows build 🤞

@gleocadie fyi, as you have interests in building on windows

[paullegranddc]

Ok, I've tried compiling locally for windows using cross , and it actually doesn't work.

I get this error

% cross check --target x86_64-pc-windows-gnu

error[E0412]: cannot find type `UnixStream` in module `tokio::net`
  --> ddprof-exporter/src/connector/conn_stream.rs:21:44
   |
21 |         Udp{ #[pin] transport: tokio::net::UnixStream },
   |                                            ^^^^^^^^^^ not found in `tokio::net`

error[E0599]: no variant named `Udp` found for enum `ConnStream`
  --> ddprof-exporter/src/connector/conn_stream.rs:21:9
   |
13 | / pin_project! {
14 | |     #[derive(Debug)]
15 | |     #[project = ConnStreamProj]
16 | |     pub enum ConnStream {
...  |
21 | |         Udp{ #[pin] transport: tokio::net::UnixStream },
   | |         ^^^ variant not found in `ConnStream`
22 | |     }
23 | | }
   | |_- variant `Udp` not found here

[paullegranddc]

Maybe if the cleaner code is worth it, we could try using https://github.com/taiki-e/pin-project instead of pin_project_lite as it supports more features.

[paullegranddc]

Or we just write the projection code ourselves. Looking at the kind of code generated by pin-project https://github.com/taiki-e/pin-project/blob/HEAD/examples/struct-default-expanded.rs , anf removing the cruft it doesn't look to bad.

[gleocadie]

#47 (comment)
TBF I'm not certain it works as expected, I'll try quickly adding a Windows build 🤞

@gleocadie fyi, as you have interests in building on windows

thanks for the heads up

[pawelchcki]

Thanks @paullegranddc - with your suggestion I reimplemented the project() method.
Its a bit verbose but not by much - explicit and visible use of Unsafe is a bit of an eyesore.

https://github.com/DataDog/libddprof/pull/47/files#diff-1d9699d6f15d9c4af24ade58efdaadaa21f28f7150cdbb6a95f65c20e8eca6f9R42-R60

Edit: after sleeing on this I decided to switch back to pin_project (non-lite) just to reduce the number of visible code lines and the unsafe eyesore (out of sight out of mind 😂 ).

[pawelchcki]

Thanks All for the review!