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1 file changed, 118 insertions
worker.rs(file created)
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| 1 | + | // NOTE: Because the mlua crate is not Sync, we can use tokio spawn_local to run the Lua VM in an async context | |
| 2 | + | // but pinned to a single thread | |
| 3 | + | // | |
| 4 | + | // This is highly experimental | |
| 5 | + | pub struct LuaWorker { | |
| 6 | + | /// A handle that allows stopping the VM inside its tokio localset | |
| 7 | + | /// | |
| 8 | + | /// This is wrapped in an option to allow destroying the handle when the LuaWorker is dropped | |
| 9 | + | pub tx_stop: Option<tokio::sync::oneshot::Sender<()>>, | |
| 10 | + | /// A channel used for sending requests to the VM | |
| 11 | + | pub tx_msg_recv: tokio::sync::mpsc::Sender<LuaWorkerRequest>, | |
| 12 | + | /// A channel that can be used to listen for a response from the VM | |
| 13 | + | pub rx_msg_resp: tokio::sync::mpsc::Receiver<LuaWorkerResponse>, | |
| 14 | + | } | |
| 15 | + | ||
| 16 | + | impl LuaWorker { | |
| 17 | + | // Executes a Lua script in the Lua VM | |
| 18 | + | pub async fn exec( | |
| 19 | + | vm: &Lua, | |
| 20 | + | template: &str, | |
| 21 | + | args: serde_json::Value, | |
| 22 | + | ) -> Result<serde_json::Value, base_data::Error> { | |
| 23 | + | let f: LuaFunction = vm | |
| 24 | + | .load(template) | |
| 25 | + | .eval_async() | |
| 26 | + | .await | |
| 27 | + | .map_err(|e| LuaError::external(e.to_string()))?; | |
| 28 | + | ||
| 29 | + | let _args = vm | |
| 30 | + | .create_table() | |
| 31 | + | .map_err(|e| LuaError::external(e.to_string()))?; | |
| 32 | + | ||
| 33 | + | let args = vm | |
| 34 | + | .to_value(&args) | |
| 35 | + | .map_err(|e| LuaError::external(e.to_string()))?; | |
| 36 | + | ||
| 37 | + | _args | |
| 38 | + | .set("args", args) | |
| 39 | + | .map_err(|e| LuaError::external(e.to_string()))?; | |
| 40 | + | ||
| 41 | + | let v: LuaValue = f | |
| 42 | + | .call_async(_args) | |
| 43 | + | .await | |
| 44 | + | .map_err(|e| LuaError::external(e.to_string()))?; | |
| 45 | + | ||
| 46 | + | let v = serde_json::to_value(v).map_err(|e| LuaError::external(e.to_string()))?; | |
| 47 | + | ||
| 48 | + | Ok(v) | |
| 49 | + | } | |
| 50 | + | ||
| 51 | + | // Spawns a new LuaWorker with the given Lua VM | |
| 52 | + | pub fn new(lua: Lua) -> Self { | |
| 53 | + | let (tx_stop, rx_stop) = tokio::sync::oneshot::channel(); | |
| 54 | + | let (tx_msg_recv, rx_msg_recv) = tokio::sync::mpsc::channel(32); | |
| 55 | + | let (tx_msg_resp, rx_msg_resp) = tokio::sync::mpsc::channel(32); | |
| 56 | + | ||
| 57 | + | let worker = LuaWorker { | |
| 58 | + | tx_stop: Some(tx_stop), | |
| 59 | + | tx_msg_recv, | |
| 60 | + | rx_msg_resp, | |
| 61 | + | }; | |
| 62 | + | ||
| 63 | + | let rt = tokio::runtime::Builder::new_current_thread() | |
| 64 | + | .enable_all() | |
| 65 | + | .build() | |
| 66 | + | .unwrap(); | |
| 67 | + | ||
| 68 | + | std::thread::spawn(move || { | |
| 69 | + | rt.block_on(async move { | |
| 70 | + | let lua = Arc::new(lua); | |
| 71 | + | let mut rx_stop = rx_stop; | |
| 72 | + | let mut rx_msg_recv = rx_msg_recv; | |
| 73 | + | let mut tx_msg_resp = tx_msg_resp; | |
| 74 | + | ||
| 75 | + | loop { | |
| 76 | + | let lua = lua.clone(); | |
| 77 | + | let tx_msg_resp = tx_msg_resp.clone(); | |
| 78 | + | ||
| 79 | + | tokio::select! { | |
| 80 | + | /*_ = rx_stop => { | |
| 81 | + | break; | |
| 82 | + | },*/ | |
| 83 | + | Some(msg) = rx_msg_recv.recv() => { | |
| 84 | + | tokio::task::spawn_local(async move { | |
| 85 | + | let lua = lua.clone(); | |
| 86 | + | let res = LuaWorker::exec(&lua, &msg.template, msg.args).await; | |
| 87 | + | let _ = tx_msg_resp.send(match res { | |
| 88 | + | Ok(v) => LuaWorkerResponse::Ok(v), | |
| 89 | + | Err(e) => LuaWorkerResponse::Err(e.to_string()), | |
| 90 | + | }); | |
| 91 | + | }); | |
| 92 | + | } | |
| 93 | + | } | |
| 94 | + | } | |
| 95 | + | }); | |
| 96 | + | }); | |
| 97 | + | ||
| 98 | + | worker | |
| 99 | + | } | |
| 100 | + | } | |
| 101 | + | ||
| 102 | + | impl Drop for LuaWorker { | |
| 103 | + | fn drop(&mut self) { | |
| 104 | + | if let Some(sender) = self.tx_stop.take() { | |
| 105 | + | let _ = sender.send(()); | |
| 106 | + | } | |
| 107 | + | } | |
| 108 | + | } | |
| 109 | + | ||
| 110 | + | pub struct LuaWorkerRequest { | |
| 111 | + | pub template: String, | |
| 112 | + | pub args: serde_json::Value, | |
| 113 | + | } | |
| 114 | + | ||
| 115 | + | pub enum LuaWorkerResponse { | |
| 116 | + | Ok(serde_json::Value), | |
| 117 | + | Err(String), | |
| 118 | + | } | |
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