Remove dependencies on OpenSSL (#4036)

* Remove dependency on hyper-tls

This removes one of the dependencies on native-tls, and thus on OpenSSL.
I will remove the other in a separate commit.

* Remove the `HttpClient` enum

It only had one variant.

* Apply suggestions from code review

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

substrate/Cargo.lock

@@ -762,6 +762,14 @@ dependencies = [
  "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ct-logs"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "sct 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ctor"
 version = "0.1.12"
@@ -1567,15 +1575,19 @@ dependencies = [
 ]
 
 [[package]]
-name = "hyper-tls"
+name = "hyper-rustls"
-version = "0.3.2"
+version = "0.17.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ct-logs 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "native-tls 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustls 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-io 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tokio-rustls 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "webpki 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "webpki-roots 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5649,7 +5661,7 @@ dependencies = [
  "futures-preview 0.3.0-alpha.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures-timer 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)",
- "hyper-tls 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hyper-rustls 0.17.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 1.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-scale-codec 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -7057,6 +7069,14 @@ dependencies = [
  "untrusted 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "webpki-roots"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "webpki 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "webpki-roots"
 version = "0.18.0"
@@ -7341,6 +7361,7 @@ dependencies = [
 "checksum crypto-mac 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4434400df11d95d556bac068ddfedd482915eb18fe8bea89bc80b6e4b1c179e5"
 "checksum csv 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "37519ccdfd73a75821cac9319d4fce15a81b9fcf75f951df5b9988aa3a0af87d"
 "checksum csv-core 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "9b5cadb6b25c77aeff80ba701712494213f4a8418fcda2ee11b6560c3ad0bf4c"
+"checksum ct-logs 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4d3686f5fa27dbc1d76c751300376e167c5a43387f44bb451fd1c24776e49113"
 "checksum ctor 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "cd8ce37ad4184ab2ce004c33bf6379185d3b1c95801cab51026bd271bf68eedc"
 "checksum ctr 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "022cd691704491df67d25d006fe8eca083098253c4d43516c2206479c58c6736"
 "checksum ctrlc 3.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c7dfd2d8b4c82121dfdff120f818e09fc4380b0b7e17a742081a89b94853e87f"
@@ -7429,7 +7450,7 @@ dependencies = [
 "checksum humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
 "checksum hyper 0.10.16 (registry+https://github.com/rust-lang/crates.io-index)" = "0a0652d9a2609a968c14be1a9ea00bf4b1d64e2e1f53a1b51b6fff3a6e829273"
 "checksum hyper 0.12.35 (registry+https://github.com/rust-lang/crates.io-index)" = "9dbe6ed1438e1f8ad955a4701e9a944938e9519f6888d12d8558b645e247d5f6"
-"checksum hyper-tls 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)" = "3a800d6aa50af4b5850b2b0f659625ce9504df908e9733b635720483be26174f"
+"checksum hyper-rustls 0.17.1 (registry+https://github.com/rust-lang/crates.io-index)" = "719d85c7df4a7f309a77d145340a063ea929dcb2e025bae46a80345cffec2952"
 "checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
 "checksum idna 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
 "checksum impl-codec 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3fa0086251524c50fd53b32e7b05eb6d79e2f97221eaf0c53c0ca9c3096f21d3"
@@ -7763,6 +7784,7 @@ dependencies = [
 "checksum wasmtime-runtime 0.2.0 (git+https://github.com/CraneStation/wasmtime.git?rev=71dd73d6)" = "<none>"
 "checksum web-sys 0.3.28 (registry+https://github.com/rust-lang/crates.io-index)" = "c84440699cd02ca23bed6f045ffb1497bc18a3c2628bd13e2093186faaaacf6b"
 "checksum webpki 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d7e664e770ac0110e2384769bcc59ed19e329d81f555916a6e072714957b81b4"
+"checksum webpki-roots 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a262ae37dd9d60f60dd473d1158f9fbebf110ba7b6a5051c8160460f6043718b"
 "checksum webpki-roots 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)" = "91cd5736df7f12a964a5067a12c62fa38e1bd8080aff1f80bc29be7c80d19ab4"
 "checksum websocket 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b255b190f412e45000c35be7fe9b48b39a2ac5eb90d093d421694e5dae8b335c"
 "checksum weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bb43f70885151e629e2a19ce9e50bd730fd436cfd4b666894c9ce4de9141164"

substrate/core/offchain/Cargo.toml

@@ -28,7 +28,7 @@ keystore = { package = "substrate-keystore", path = "../keystore" }
 
 [target.'cfg(not(target_os = "unknown"))'.dependencies]
 hyper = "0.12.35"
-hyper-tls = "0.3.2"
+hyper-rustls = "0.17.1"
 
 [dev-dependencies]
 env_logger = "0.7.0"

substrate/core/offchain/src/api/http.rs

@@ -29,7 +29,7 @@ use crate::api::timestamp;
 use bytes::Buf as _;
 use fnv::FnvHashMap;
 use futures::{prelude::*, channel::mpsc, compat::Compat01As03};
-use log::{warn, error};
+use log::error;
 use primitives::offchain::{HttpRequestId, Timestamp, HttpRequestStatus, HttpError};
 use std::{fmt, io::Read as _, mem, pin::Pin, task::Context, task::Poll};
 
@@ -50,9 +50,7 @@ pub fn http() -> (HttpApi, HttpWorker) {
 	let engine = HttpWorker {
 		to_api,
 		from_api,
-		// TODO: don't unwrap; we should fall back to the HttpConnector if we fail to create the
+		http_client: hyper::Client::builder().build(hyper_rustls::HttpsConnector::new(1)),
-		// Https one; there doesn't seem to be any built-in way to do this
-		http_client: HyperClient::new(),
 		requests: Vec::new(),
 	};
 
@@ -551,30 +549,6 @@ enum WorkerToApi {
 	},
 }
 
-/// Wraps around a `hyper::Client` with either TLS enabled or disabled.
-enum HyperClient {
-	/// Everything is ok and HTTPS is available.
-	Https(hyper::Client<hyper_tls::HttpsConnector<hyper::client::HttpConnector>, hyper::Body>),
-	/// We failed to initialize HTTPS and therefore only allow HTTP.
-	Http(hyper::Client<hyper::client::HttpConnector, hyper::Body>),
-}
-
-impl HyperClient {
-	/// Creates new hyper client.
-	///
-	/// By default we will try to initialize the `HttpsConnector`,
-	/// If that's not possible we'll fall back to `HttpConnector`.
-	pub fn new() -> Self {
-		match hyper_tls::HttpsConnector::new(1) {
-			Ok(tls) => HyperClient::Https(hyper::Client::builder().build(tls)),
-			Err(e) => {
-				warn!("Unable to initialize TLS client. Falling back to HTTP-only: {:?}", e);
-				HyperClient::Http(hyper::Client::new())
-			},
-		}
-	}
-}
-
 /// Must be continuously polled for the [`HttpApi`] to properly work.
 pub struct HttpWorker {
 	/// Used to sends messages to the `HttpApi`.
@@ -582,7 +556,7 @@ pub struct HttpWorker {
 	/// Used to receive messages from the `HttpApi`.
 	from_api: mpsc::UnboundedReceiver<ApiToWorker>,
 	/// The engine that runs HTTP requests.
-	http_client: HyperClient,
+	http_client: hyper::Client<hyper_rustls::HttpsConnector<hyper::client::HttpConnector>, hyper::Body>,
 	/// HTTP requests that are being worked on by the engine.
 	requests: Vec<(HttpRequestId, HttpWorkerRequest)>,
 }
@@ -686,10 +660,7 @@ impl Future for HttpWorker {
 			Poll::Pending => {},
 			Poll::Ready(None) => return Poll::Ready(()),	// stops the worker
 			Poll::Ready(Some(ApiToWorker::Dispatch { id, request })) => {
-				let future = Compat01As03::new(match me.http_client {
+				let future = Compat01As03::new(me.http_client.request(request));
-					HyperClient::Http(ref mut c) => c.request(request),
-					HyperClient::Https(ref mut c) => c.request(request),
-				});
 				debug_assert!(me.requests.iter().all(|(i, _)| *i != id));
 				me.requests.push((id, HttpWorkerRequest::Dispatched(future)));
 				cx.waker().wake_by_ref();	// reschedule the task to poll the request