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use std::pin::Pin;
use std::time::Duration;
use async_trait::async_trait;
use futures::StreamExt;
use pubnub_hyper::core::data::{channel, message::Type};
use pubnub_hyper::{Builder, DefaultRuntime, DefaultTransport, PubNub};
use timely::scheduling::SyncActivator;
use tracing::info;
use mz_expr::PartitionId;
use mz_repr::{Datum, GlobalId, Row};
use crate::source::{SourceMessage, SourceMessageType, SourceReader, SourceReaderError};
use crate::types::connections::ConnectionContext;
use crate::types::sources::{encoding::SourceDataEncoding, MzOffset, SourceConnection};
pub struct PubNubSourceReader {
channel: channel::Name,
pubnub: PubNub,
stream: Option<Pin<Box<pubnub_hyper::core::Subscription<DefaultRuntime>>>>,
}
#[async_trait(?Send)]
impl SourceReader for PubNubSourceReader {
type Key = ();
type Value = Row;
type Diff = ();
fn new(
_source_name: String,
_source_id: GlobalId,
_worker_id: usize,
_worker_count: usize,
_consumer_activator: SyncActivator,
connection: SourceConnection,
_restored_offsets: Vec<(PartitionId, Option<MzOffset>)>,
_encoding: SourceDataEncoding,
_: crate::source::metrics::SourceBaseMetrics,
_: ConnectionContext,
) -> Result<Self, anyhow::Error> {
let pubnub_conn = match connection {
SourceConnection::PubNub(pubnub_conn) => pubnub_conn,
_ => {
panic!("PubNub is the only legitimate SourceConnection for PubNubSourceReader")
}
};
let transport = DefaultTransport::new()
.publish_key("")
.subscribe_key(&pubnub_conn.subscribe_key)
.build()?;
let pubnub = Builder::new()
.transport(transport)
.runtime(DefaultRuntime)
.build();
let channel = pubnub_conn.channel;
let channel: channel::Name = channel
.parse()
.or_else(|_| Err(anyhow::anyhow!("invalid pubnub channel: {}", channel)))?;
Ok(Self {
channel,
pubnub,
stream: None,
})
}
async fn next(
&mut self,
timestamp_frequency: Duration,
) -> Option<Result<SourceMessageType<Self::Key, Self::Value, Self::Diff>, SourceReaderError>>
{
loop {
let stream = match &mut self.stream {
None => {
self.stream = Some(Box::pin(self.pubnub.subscribe(self.channel.clone()).await));
self.stream.as_mut().expect("we just created the stream")
}
Some(stream) => stream,
};
match stream.next().await {
Some(msg) => {
if msg.message_type == Type::Publish {
let s = msg.json.dump();
let row = Row::pack_slice(&[Datum::String(&s)]);
return Some(Ok(SourceMessageType::Finalized(SourceMessage {
partition: PartitionId::None,
offset: MzOffset {
offset: msg.timetoken.t,
},
upstream_time_millis: None,
key: (),
value: row,
headers: None,
specific_diff: (),
})));
}
}
None => {
info!(
"pubnub channel {:?} disconnected. reconnecting",
self.channel.to_string()
);
self.stream.take();
tokio::time::sleep(timestamp_frequency).await;
}
}
}
}
}