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| 1 | +use std::sync::Arc; |
| 2 | +use std::time::Duration; |
| 3 | + |
| 4 | +use async_trait::async_trait; |
| 5 | +use futures::{Sink, SinkExt, StreamExt, stream}; |
| 6 | +use tokio::net::TcpListener; |
| 7 | +use tokio::time::sleep; |
| 8 | + |
| 9 | +use pgwire::api::auth::noop::NoopStartupHandler; |
| 10 | +use pgwire::api::cancel::DefaultCancelHandler; |
| 11 | +use pgwire::api::query::SimpleQueryHandler; |
| 12 | +use pgwire::api::results::{FieldFormat, FieldInfo, QueryResponse, Response, Tag}; |
| 13 | +use pgwire::api::store::PortalStore; |
| 14 | +use pgwire::api::{ClientInfo, ClientPortalStore, ConnectionManager, PgWireServerHandlers, Type}; |
| 15 | +use pgwire::error::{ErrorInfo, PgWireError, PgWireResult}; |
| 16 | +use pgwire::messages::response::NoticeResponse; |
| 17 | +use pgwire::messages::{PgWireBackendMessage, PgWireFrontendMessage}; |
| 18 | +use pgwire::tokio::process_socket; |
| 19 | + |
| 20 | +struct SlowProcessor { |
| 21 | + manager: Arc<ConnectionManager>, |
| 22 | +} |
| 23 | + |
| 24 | +#[async_trait] |
| 25 | +impl NoopStartupHandler for SlowProcessor { |
| 26 | + fn connection_manager(&self) -> Option<Arc<ConnectionManager>> { |
| 27 | + Some(self.manager.clone()) |
| 28 | + } |
| 29 | + |
| 30 | + async fn post_startup<C>( |
| 31 | + &self, |
| 32 | + client: &mut C, |
| 33 | + _message: PgWireFrontendMessage, |
| 34 | + ) -> PgWireResult<()> |
| 35 | + where |
| 36 | + C: ClientInfo + Sink<PgWireBackendMessage> + Unpin + Send, |
| 37 | + C::Error: std::fmt::Debug, |
| 38 | + PgWireError: From<<C as Sink<PgWireBackendMessage>>::Error>, |
| 39 | + { |
| 40 | + client |
| 41 | + .send(PgWireBackendMessage::NoticeResponse(NoticeResponse::from( |
| 42 | + ErrorInfo::new( |
| 43 | + "NOTICE".to_owned(), |
| 44 | + "01000".to_owned(), |
| 45 | + "This example demonstrates query cancellation.\n\ |
| 46 | + Supported queries:\n\ |
| 47 | + - SELECT 1; (instant query)\n\ |
| 48 | + - SELECT pg_sleep(10); (sleeps 10s, press Ctrl+C to cancel)" |
| 49 | + .to_string(), |
| 50 | + ), |
| 51 | + ))) |
| 52 | + .await?; |
| 53 | + Ok(()) |
| 54 | + } |
| 55 | +} |
| 56 | + |
| 57 | +#[async_trait] |
| 58 | +impl SimpleQueryHandler for SlowProcessor { |
| 59 | + async fn do_query<C>(&self, _client: &mut C, query: &str) -> PgWireResult<Vec<Response>> |
| 60 | + where |
| 61 | + C: ClientInfo + ClientPortalStore + Unpin + Send + Sync, |
| 62 | + C::PortalStore: PortalStore, |
| 63 | + { |
| 64 | + if query.trim().starts_with("SELECT pg_sleep") { |
| 65 | + sleep(Duration::from_secs(10)).await; |
| 66 | + Ok(vec![Response::Execution(Tag::new("SELECT 1"))]) |
| 67 | + } else if query.trim().starts_with("SELECT") { |
| 68 | + let f1 = FieldInfo::new("id".into(), None, None, Type::INT4, FieldFormat::Text); |
| 69 | + let schema = Arc::new(vec![f1]); |
| 70 | + let data = vec![(Some(1),), (Some(2),), (Some(3),)]; |
| 71 | + let schema_ref = schema.clone(); |
| 72 | + let data_row_stream = stream::iter(data).map(move |r| { |
| 73 | + let mut encoder = pgwire::api::results::DataRowEncoder::new(schema_ref.clone()); |
| 74 | + encoder.encode_field(&r.0)?; |
| 75 | + Ok(encoder.take_row()) |
| 76 | + }); |
| 77 | + Ok(vec![Response::Query(QueryResponse::new( |
| 78 | + schema, |
| 79 | + data_row_stream, |
| 80 | + ))]) |
| 81 | + } else { |
| 82 | + Ok(vec![Response::Execution(Tag::new("OK").with_rows(1))]) |
| 83 | + } |
| 84 | + } |
| 85 | +} |
| 86 | + |
| 87 | +struct HandlerFactory { |
| 88 | + processor: Arc<SlowProcessor>, |
| 89 | + cancel_handler: Arc<DefaultCancelHandler>, |
| 90 | +} |
| 91 | + |
| 92 | +impl PgWireServerHandlers for HandlerFactory { |
| 93 | + fn simple_query_handler(&self) -> Arc<impl SimpleQueryHandler> { |
| 94 | + self.processor.clone() |
| 95 | + } |
| 96 | + |
| 97 | + fn startup_handler(&self) -> Arc<impl pgwire::api::auth::StartupHandler> { |
| 98 | + self.processor.clone() |
| 99 | + } |
| 100 | + |
| 101 | + fn cancel_handler(&self) -> Arc<impl pgwire::api::cancel::CancelHandler> { |
| 102 | + self.cancel_handler.clone() |
| 103 | + } |
| 104 | +} |
| 105 | + |
| 106 | +#[tokio::main] |
| 107 | +pub async fn main() { |
| 108 | + let manager = Arc::new(ConnectionManager::new()); |
| 109 | + let processor = Arc::new(SlowProcessor { |
| 110 | + manager: manager.clone(), |
| 111 | + }); |
| 112 | + let cancel_handler = Arc::new(DefaultCancelHandler::new(manager)); |
| 113 | + let factory = Arc::new(HandlerFactory { |
| 114 | + processor, |
| 115 | + cancel_handler, |
| 116 | + }); |
| 117 | + |
| 118 | + let server_addr = "127.0.0.1:5432"; |
| 119 | + let listener = TcpListener::bind(server_addr).await.unwrap(); |
| 120 | + println!("Listening to {}", server_addr); |
| 121 | + println!("Connect with: psql -h 127.0.0.1 -p 5432"); |
| 122 | + println!("Test cancel: SELECT pg_sleep(10); then press Ctrl+C"); |
| 123 | + loop { |
| 124 | + let incoming_socket = listener.accept().await.unwrap(); |
| 125 | + let factory_ref = factory.clone(); |
| 126 | + tokio::spawn(async move { process_socket(incoming_socket.0, None, factory_ref).await }); |
| 127 | + } |
| 128 | +} |
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