Library: Add compatibility for legacy Tokio 0.2 (#40)

Adds support to the library for tokio 0.2 backward-compatibility. This should hopefully benefit, and prevent lavalink-rs from being blocked on this feature.

These can be reached using, e.g., `gateway-tokio-02`, `driver-tokio-02`, `serenity-rustls-tokio-02`, and `serenity-native-tokio-02` features.

Naturally, this requires some jiggering about with features and the underlying CI, which has been taken care of. Twilight can't be handled in this way, as their last tokio 0.2 version uses the deprecated Discord Gateway v6.

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
       uses: actions-rs/clippy-check@v1
       with:
         token: ${{ secrets.GITHUB_TOKEN }}
-        args: --all-features
+        args: --features full-doc
 
   test:
     name: Test
@@ -39,6 +39,7 @@ jobs:
           - Windows
           - driver only
           - gateway only
+          - legacy tokio
 
         include:
           - name: beta
@@ -51,8 +52,13 @@ jobs:
             os: windows-latest
           - name: driver only
             features: driver rustls
+            dont-test: true
           - name: gateway only
             features: serenity-rustls
+            dont-test: true
+          - name: legacy tokio
+            features: serenity-rustls-tokio-02 driver-tokio-02
+            dont-test: true
 
     steps:
       - name: Checkout sources
@@ -84,18 +90,18 @@ jobs:
 
       - name: Build all features
         if: matrix.features == ''
-        run: cargo build --all-features
+        run: cargo build --features full-doc
 
       - name: Test all features
         if: matrix.features == ''
-        run: cargo test --all-features
+        run: cargo test --features full-doc
 
       - name: Build some features
         if: matrix.features
         run: cargo build --no-default-features --features "${{ matrix.features }}"
 
       - name: Test some features
-        if: matrix.features
+        if: ${{ !matrix.dont-test && matrix.features }}
         run: cargo test --no-default-features --features "${{ matrix.features }}"
 
   doc:
@@ -131,7 +137,7 @@ jobs:
         env:
           RUSTDOCFLAGS: -D broken_intra_doc_links
         run: |
-          cargo doc --no-deps --all-features
+          cargo doc --no-deps --features full-doc
 
   examples:
     name: Examples

.github/workflows/docs.yml

@@ -41,7 +41,7 @@ jobs:
         env:
           RUSTDOCFLAGS: -D broken_intra_doc_links
         run: |
-          cargo doc --no-deps --features default,twilight-rustls,builtin-queue,stock-zlib
+          cargo doc --no-deps --features full-doc
 
       - name: Prepare docs
         shell: bash -e -O extglob {0}

Cargo.toml

@@ -28,6 +28,13 @@ features = ["tokio-runtime"]
 optional = true
 version = "0.11"
 
+[dependencies.async-tungstenite-compat]
+package = "async-tungstenite"
+default-features = false
+features = ["tokio-runtime"]
+optional = true
+version = "0.9"
+
 [dependencies.audiopus]
 optional = true
 version = "0.2"
@@ -62,7 +69,7 @@ version = "0.8"
 
 [dependencies.serenity]
 optional = true
-version = "0.10"
+version = "^0.10.2"
 default-features = false
 features = ["voice", "gateway"]
 
@@ -83,6 +90,12 @@ optional = true
 version = "1.0"
 default-features = false
 
+[dependencies.tokio-compat]
+optional = true
+package = "tokio"
+version = "0.2"
+default-features = false
+
 [dependencies.twilight-gateway]
 optional = true
 version = "0.3"
@@ -115,20 +128,35 @@ criterion = "0.3"
 utils = { path = "utils" }
 
 [features]
+# Core features
 default = [
     "serenity-rustls",
     "driver",
     "gateway",
 ]
 gateway = [
+    "gateway-core",
+    "tokio/sync",
+]
+gateway-core = [
     "dashmap",
     "flume",
     "parking_lot",
-    "tokio/sync",
 ]
 driver = [
-    "async-trait",
     "async-tungstenite",
+    "driver-core",
+    "tokio/fs",
+    "tokio/io-util",
+    "tokio/macros",
+    "tokio/net",
+    "tokio/process",
+    "tokio/rt",
+    "tokio/sync",
+    "tokio/time",
+]
+driver-core = [
+    "async-trait",
     "audiopus",
     "byteorder",
     "discortp",
@@ -138,21 +166,13 @@ driver = [
     "serenity-voice-model",
     "spin_sleep",
     "streamcatcher",
-    "tokio/fs",
-    "tokio/io-util",
-    "tokio/macros",
-    "tokio/net",
-    "tokio/process",
-    "tokio/rt",
-    "tokio/sync",
-    "tokio/time",
     "typemap_rev",
     "url",
     "uuid",
     "xsalsa20poly1305",
 ]
-rustls = ["async-tungstenite/tokio-rustls"]
-native = ["async-tungstenite/tokio-native-tls"]
+rustls = ["async-tungstenite/tokio-rustls", "rustls-marker"]
+native = ["async-tungstenite/tokio-native-tls", "native-marker"]
 serenity-rustls = ["serenity/rustls_backend", "rustls", "gateway", "serenity-deps"]
 serenity-native = ["serenity/native_tls_backend", "native", "gateway", "serenity-deps"]
 twilight-rustls = ["twilight", "twilight-gateway/rustls", "rustls", "gateway"]
@@ -162,9 +182,41 @@ simd-zlib = ["twilight-gateway/simd-zlib"]
 stock-zlib = ["twilight-gateway/stock-zlib"]
 serenity-deps = ["async-trait"]
 
+rustls-marker = []
+native-marker = []
+
+# Tokio 0.2 Compatibility features
+# These should probably be dropped around the same time as serenity drop them.
+rustls-tokio-02 = ["async-tungstenite-compat/tokio-rustls", "rustls-marker", "tokio-02-marker"]
+native-tokio-02 = ["async-tungstenite-compat/tokio-native-tls", "native-marker", "tokio-02-marker"]
+serenity-rustls-tokio-02 = ["serenity/rustls_tokio_0_2_backend", "rustls-tokio-02", "gateway-tokio-02", "serenity-deps"]
+serenity-native-tokio-02 = ["serenity/native_tls_tokio_0_2_backend", "native-tokio-02", "gateway-tokio-02", "serenity-deps"]
+gateway-tokio-02 = [
+    "gateway-core",
+    "tokio-02-marker",
+    "tokio-compat/sync",
+]
+driver-tokio-02 = [
+    "async-tungstenite-compat",
+    "driver-core",
+    "tokio-02-marker",
+    "tokio-compat/fs",
+    "tokio-compat/io-util",
+    "tokio-compat/macros",
+    "tokio-compat/net",
+    "tokio-compat/process",
+    "tokio-compat/rt-core",
+    "tokio-compat/sync",
+    "tokio-compat/time",
+]
+tokio-02-marker = []
+
+# Behaviour altering features.
 youtube-dlc = []
 builtin-queue = []
 
+# Used for docgen/testing/benchmarking.
+full-doc = ["default", "twilight-rustls", "builtin-queue", "stock-zlib"]
 internals = []
 
 [[bench]]
@@ -179,4 +231,4 @@ required-features = ["internals"]
 harness = false
 
 [package.metadata.docs.rs]
-features = ["default", "twilight-rustls", "builtin-queue", "stock-zlib"]
+features = ["full-doc"]

build.rs

@@ -1,4 +1,7 @@
-#[cfg(all(feature = "driver", not(any(feature = "rustls", feature = "native"))))]
+#[cfg(all(
+    feature = "driver",
+    not(any(feature = "rustls-marker", feature = "native-marker"))
+))]
 compile_error!(
     "You have the `driver` feature enabled: \
     either the `rustls` or `native` feature must be

src/constants.rs

@@ -1,16 +1,16 @@
 //! Constants affecting driver function and API handling.
 
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 use audiopus::{Bitrate, SampleRate};
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 use discortp::rtp::RtpType;
 use std::time::Duration;
 
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 /// The voice gateway version used by the library.
 pub const VOICE_GATEWAY_VERSION: u8 = crate::model::constants::GATEWAY_VERSION;
 
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 /// Sample rate of audio to be sent to Discord.
 pub const SAMPLE_RATE: SampleRate = SampleRate::Hz48000;
 
@@ -23,7 +23,7 @@ pub const AUDIO_FRAME_RATE: usize = 50;
 /// Length of time between any two audio frames.
 pub const TIMESTEP_LENGTH: Duration = Duration::from_millis(1000 / AUDIO_FRAME_RATE as u64);
 
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 /// Default bitrate for audio.
 pub const DEFAULT_BITRATE: Bitrate = Bitrate::BitsPerSecond(128_000);
 
@@ -70,6 +70,6 @@ pub const SILENT_FRAME: [u8; 3] = [0xf8, 0xff, 0xfe];
 /// The one (and only) RTP version.
 pub const RTP_VERSION: u8 = 2;
 
-#[cfg(feature = "driver")]
+#[cfg(feature = "driver-core")]
 /// Profile type used by Discord's Opus audio traffic.
 pub const RTP_PROFILE_TYPE: RtpType = RtpType::Dynamic(120);

src/driver/connection/mod.rs

@@ -19,15 +19,18 @@ use discortp::discord::{IpDiscoveryPacket, IpDiscoveryType, MutableIpDiscoveryPa
 use error::{Error, Result};
 use flume::Sender;
 use std::{net::IpAddr, str::FromStr, sync::Arc};
-use tokio::net::UdpSocket;
+#[cfg(not(feature = "tokio-02-marker"))]
+use tokio::{net::UdpSocket, spawn};
+#[cfg(feature = "tokio-02-marker")]
+use tokio_compat::{net::UdpSocket, spawn};
 use tracing::{debug, info, instrument};
 use url::Url;
 use xsalsa20poly1305::{aead::NewAead, XSalsa20Poly1305 as Cipher};
 
-#[cfg(all(feature = "rustls", not(feature = "native")))]
+#[cfg(all(feature = "rustls-marker", not(feature = "native-marker")))]
 use ws::create_rustls_client;
 
-#[cfg(feature = "native")]
+#[cfg(feature = "native-marker")]
 use ws::create_native_tls_client;
 
 pub(crate) struct Connection {
@@ -43,10 +46,10 @@ impl Connection {
     ) -> Result<Connection> {
         let url = generate_url(&mut info.endpoint)?;
 
-        #[cfg(all(feature = "rustls", not(feature = "native")))]
+        #[cfg(all(feature = "rustls-marker", not(feature = "native-marker")))]
         let mut client = create_rustls_client(url).await?;
 
-        #[cfg(feature = "native")]
+        #[cfg(feature = "native-marker")]
         let mut client = create_native_tls_client(url).await?;
 
         let mut hello = None;
@@ -97,7 +100,11 @@ impl Connection {
             return Err(Error::CryptoModeUnavailable);
         }
 
+        #[cfg(not(feature = "tokio-02-marker"))]
         let udp = UdpSocket::bind("0.0.0.0:0").await?;
+        #[cfg(feature = "tokio-02-marker")]
+        let mut udp = UdpSocket::bind("0.0.0.0:0").await?;
+
         udp.connect((ready.ip, ready.port)).await?;
 
         // Follow Discord's IP Discovery procedures, in case NAT tunnelling is needed.
@@ -124,7 +131,7 @@ impl Connection {
             }
 
             // We could do something clever like binary search,
-            // but possibility of UDP spoofing preclueds us from
+            // but possibility of UDP spoofing precludes us from
             // making the assumption we can find a "left edge" of '\0's.
             let nul_byte_index = view
                 .get_address_raw()
@@ -162,8 +169,14 @@ impl Connection {
         let (udp_sender_msg_tx, udp_sender_msg_rx) = flume::unbounded();
         let (udp_receiver_msg_tx, udp_receiver_msg_rx) = flume::unbounded();
 
-        let udp_rx = Arc::new(udp);
-        let udp_tx = Arc::clone(&udp_rx);
+        #[cfg(not(feature = "tokio-02-marker"))]
+        let (udp_rx, udp_tx) = {
+            let udp_rx = Arc::new(udp);
+            let udp_tx = Arc::clone(&udp_rx);
+            (udp_rx, udp_tx)
+        };
+        #[cfg(feature = "tokio-02-marker")]
+        let (udp_rx, udp_tx) = udp.split();
 
         let ssrc = ready.ssrc;
 
@@ -182,22 +195,22 @@ impl Connection {
             .mixer
             .send(MixerMessage::SetConn(mix_conn, ready.ssrc))?;
 
-        tokio::spawn(ws_task::runner(
+        spawn(ws_task::runner(
             interconnect.clone(),
             ws_msg_rx,
             client,
             ssrc,
             hello.heartbeat_interval,
         ));
 
-        tokio::spawn(udp_rx::runner(
+        spawn(udp_rx::runner(
             interconnect.clone(),
             udp_receiver_msg_rx,
             cipher,
             config.clone(),
             udp_rx,
         ));
-        tokio::spawn(udp_tx::runner(udp_sender_msg_rx, ssrc, udp_tx));
+        spawn(udp_tx::runner(udp_sender_msg_rx, ssrc, udp_tx));
 
         Ok(Connection {
             info,
@@ -212,10 +225,10 @@ impl Connection {
         // Thread may have died, we want to send to prompt a clean exit
         // (if at all possible) and then proceed as normal.
 
-        #[cfg(all(feature = "rustls", not(feature = "native")))]
+        #[cfg(all(feature = "rustls-marker", not(feature = "native-marker")))]
         let mut client = create_rustls_client(url).await?;
 
-        #[cfg(feature = "native")]
+        #[cfg(feature = "native-marker")]
         let mut client = create_native_tls_client(url).await?;
 
         client

src/driver/tasks/message/mod.rs

@@ -11,6 +11,10 @@ mod ws;
 pub use self::{core::*, disposal::*, events::*, mixer::*, udp_rx::*, udp_tx::*, ws::*};
 
 use flume::Sender;
+#[cfg(not(feature = "tokio-02-marker"))]
+use tokio::spawn;
+#[cfg(feature = "tokio-02-marker")]
+use tokio_compat::spawn;
 use tracing::info;
 
 #[derive(Clone, Debug)]
@@ -38,7 +42,7 @@ impl Interconnect {
         self.events = evt_tx;
 
         let ic = self.clone();
-        tokio::spawn(async move {
+        spawn(async move {
             info!("Event processor restarted.");
             super::events::runner(ic, evt_rx).await;
             info!("Event processor finished.");