Add rustls feature

[enfipy]

Currently sqlx-rt uses native-tls. But library native-tls is dynamically linked and it's hard sometimes to set up the environment for it (ex. docker image).

But hopefully, there are rustls and tokio-rustls that can statically link SSL during compilation. I think it will be useful for many developers to have it.

Similar feature exists in actix-web.

[mehcode]

It's not possible for Cargo to activate a feature dependent on another feature in a workable fashion. We would want tls-native and tls-rustls as features (perhaps with the first being default). tls-native would need to turn on tokio-tls if runtime-tokio or async-native-tls if runtime-actix-std.

So this is blocked on rust-lang/cargo#3494

I definitely do want this though.

[olvyko]

@mehcode Maybe there is some workaround for this, because we really need rustls. Or only a fork help in this case?

[JADSN]

Besides, with rustls support we can build sqlx to musl target.

[mehcode]

I'm not aware of a way to work-around this outside of a fork. If you can figure out a way, I'll merge a PR.

---

Besides, with rustls support we can build sqlx to musl target.

You can do that now by vendoring OpenSSL. We (LaunchBadge) do this for our production services.

See #473 (comment)

[olvyko]

One way is to add two more features 'runtime-actix-rustls' and 'runtime-tokio-rustls' to sqlx-rt.
https://github.com/olvyko/sqlx/commit/0fd74fa0c9c8f16e55d540b89792b9946d776332
But as I see, sqlx-core depends on native-tls code that exported from sqlx-rt so it should be changed too

[repnop]

Sorry if this is a silly question, but is there a reason to not switch to rustls wholesale and get rid of native-tls?

[jplatte]

One way is to add two more features 'runtime-actix-rustls' and 'runtime-tokio-rustls' to sqlx-rt.
olvyko@0fd74fa
But as I see, sqlx-core depends on native-tls code that exported from sqlx-rt so it should be changed too

I don't think passing through the feature from one sqlx crate to another is a problem. The only problem I can see is that this is a breaking change. Since there is no default runtime, you also couldn't set a default [TLS backend + runtime combination] and it would have to be selected explicitly, like runtimes now.

@mehcode Would you be open to a PR that doubles the amount of "runtimes" by having a native-tls and a rustls variant of each (or triples it to also allow no tls)?

[Absolucy]

There's mostly API-identical alternatives to tokio-native-tls and async-native-tls: tokio-rustls and async-tls

tokio-rustls is being stubborn to convert to, though?

error[E0308]: mismatched types
  --> sqlx-core/src/net/tls.rs:49:26
   |
49 |                 .connect(host, stream)
   |                          ^^^^ expected struct `sqlx_rt::tokio_rustls::webpki::DNSNameRef`, found `&str`

error[E0308]: mismatched types
  --> sqlx-core/src/net/tls.rs:49:26
   |
49 |                 .connect(host, stream)
   |                          ^^^^ expected struct `sqlx_rt::tokio_rustls::webpki::DNSNameRef`, found `&str`

error[E0308]: try expression alternatives have incompatible types
  --> sqlx-core/src/net/tls.rs:48:13
   |
48 | /             connector
49 | |                 .connect(host, stream)
50 | |                 .await
51 | |                 .map_err(|err| Error::Tls(err.into()))?,
   | |_______________________________________________________^ expected enum `sqlx_rt::TlsStream`, found struct `sqlx_rt::tokio_rustls::client::TlsStream`
   |
   = note: expected enum `sqlx_rt::TlsStream<S>`
            found struct `sqlx_rt::tokio_rustls::client::TlsStream<S>`
help: try using a variant of the expected enum
   |
48 |             sqlx_rt::TlsStream::Client(connector
49 |                 .connect(host, stream)
50 |                 .await
51 |                 .map_err(|err| Error::Tls(err.into()))?),
   |

error[E0308]: try expression alternatives have incompatible types
  --> sqlx-core/src/net/tls.rs:48:13
   |
48 | /             connector
49 | |                 .connect(host, stream)
50 | |                 .await
51 | |                 .map_err(|err| Error::Tls(err.into()))?,
   | |_______________________________________________________^ expected enum `sqlx_rt::TlsStream`, found struct `sqlx_rt::tokio_rustls::client::TlsStream`
   |
   = note: expected enum `sqlx_rt::TlsStream<S>`
            found struct `sqlx_rt::tokio_rustls::client::TlsStream<S>`
help: try using a variant of the expected enum
   |
48 |             sqlx_rt::TlsStream::Client(connector
49 |                 .connect(host, stream)
50 |                 .await
51 |                 .map_err(|err| Error::Tls(err.into()))?),
   |

error[E0599]: no method named `get_ref` found for tuple `(&S, &dyn sqlx_rt::tokio_rustls::rustls::Session)` in the current scope
   --> sqlx-core/src/net/tls.rs:170:51
    |
170 |             MaybeTlsStream::Tls(s) => s.get_ref().get_ref().get_ref(),
    |                                                   ^^^^^^^ method not found in `(&S, &dyn sqlx_rt::tokio_rustls::rustls::Session)`

error[E0599]: no method named `get_ref` found for tuple `(&S, &dyn sqlx_rt::tokio_rustls::rustls::Session)` in the current scope
   --> sqlx-core/src/net/tls.rs:170:51
    |
170 |             MaybeTlsStream::Tls(s) => s.get_ref().get_ref().get_ref(),
    |                                                   ^^^^^^^ method not found in `(&S, &dyn sqlx_rt::tokio_rustls::rustls::Session)`

error[E0599]: no method named `get_mut` found for tuple `(&mut S, &mut dyn sqlx_rt::tokio_rustls::rustls::Session)` in the current scope
   --> sqlx-core/src/net/tls.rs:189:51
    |
189 |             MaybeTlsStream::Tls(s) => s.get_mut().get_mut().get_mut(),
    |                                                   ^^^^^^^ method not found in `(&mut S, &mut dyn sqlx_rt::tokio_rustls::rustls::Session)`

error[E0599]: no method named `get_mut` found for tuple `(&mut S, &mut dyn sqlx_rt::tokio_rustls::rustls::Session)` in the current scope
   --> sqlx-core/src/net/tls.rs:189:51
    |
189 |             MaybeTlsStream::Tls(s) => s.get_mut().get_mut().get_mut(),
    |                                                   ^^^^^^^ method not found in `(&mut S, &mut dyn sqlx_rt::tokio_rustls::rustls::Session)`

error: aborting due to 4 previous errors; 4 warnings emitted

[jplatte]

#735 implements this and is now ready for review 🙂

[jplatte]

#735 was merged in a way that GitHub didn't pick up (and is part of SQLx 0.4), this can be closed 🙂