chore(splunk_hec source): Update to futures 0.3 (#7225)

* Update source

Signed-off-by: ktf <krunotf@gmail.com>

* Use forward

Signed-off-by: ktf <krunotf@gmail.com>

src/sources/splunk_hec.rs

@@ -11,8 +11,7 @@ use crate::{
 use bytes::{Buf, Bytes};
 use chrono::{DateTime, TimeZone, Utc};
 use flate2::read::MultiGzDecoder;
-use futures::{FutureExt, SinkExt, StreamExt, TryFutureExt};
-use futures01::{Async, Stream};
+use futures::{stream, FutureExt, SinkExt, StreamExt, TryFutureExt};
 use http::StatusCode;
 use serde::{de, Deserialize, Serialize};
 use serde_json::{de::IoRead, json, Deserializer, Value as JsonValue};
@@ -173,7 +172,26 @@ impl SplunkSource {
                       host: Option<String>,
                       gzip: bool,
                       body: Bytes| {
-                    process_service_request(out.clone(), channel, host, gzip, body)
+                    let mut out = out
+                        .clone()
+                        .sink_map_err(|_| Rejection::from(ApiError::ServerShutdown));
+                    async move {
+                        let reader: Box<dyn Read + Send> = if gzip {
+                            Box::new(MultiGzDecoder::new(body.reader()))
+                        } else {
+                            Box::new(body.reader())
+                        };
+
+                        let events = stream::iter(EventIterator::new(reader, channel, host));
+
+                        // `fn send_all` can be used once https://github.com/rust-lang/futures-rs/issues/2402
+                        // is resolved.
+                        let res = events.forward(&mut out).await;
+
+                        out.flush().await?;
+
+                        res
+                    }
                 },
             )
             .map(finish_ok)
@@ -293,37 +311,9 @@ impl SplunkSource {
     }
 }
 
-async fn process_service_request(
-    out: Pipeline,
-    channel: Option<String>,
-    host: Option<String>,
-    gzip: bool,
-    body: Bytes,
-) -> Result<(), Rejection> {
-    use futures::compat::Stream01CompatExt;
-
-    let mut out = out.sink_map_err(|_| Rejection::from(ApiError::ServerShutdown));
-
-    let reader: Box<dyn Read + Send> = if gzip {
-        Box::new(MultiGzDecoder::new(body.reader()))
-    } else {
-        Box::new(body.reader())
-    };
-
-    let stream = EventStream::new(reader, channel, host).compat();
-
-    let res = stream.forward(&mut out).await;
-
-    out.flush()
-        .map_err(|_| Rejection::from(ApiError::ServerShutdown))
-        .await?;
-
-    res.map(|_| ())
-}
-
-/// Constructs one ore more events from json-s coming from reader.
+/// Constructs one or more events from json-s coming from reader.
 /// If errors, it's done with input.
-struct EventStream<R: Read> {
+struct EventIterator<R: Read> {
     /// Remaining request with JSON events
     data: R,
     /// Count of sent events
@@ -336,9 +326,9 @@ struct EventStream<R: Read> {
     extractors: [DefaultExtractor; 4],
 }
 
-impl<R: Read> EventStream<R> {
+impl<R: Read> EventIterator<R> {
     fn new(data: R, channel: Option<String>, host: Option<String>) -> Self {
-        EventStream {
+        EventIterator {
             data,
             events: 0,
             channel: channel.map(Value::from),
@@ -365,30 +355,8 @@ impl<R: Read> EventStream<R> {
             Some(_) => Deserialize::deserialize(&mut Deserializer::new(reader)).map(Some),
         }
     }
-}
-
-impl<R: Read> Stream for EventStream<R> {
-    type Item = Event;
-    type Error = Rejection;
-    fn poll(&mut self) -> Result<Async<Option<Event>>, Rejection> {
-        // Parse JSON object
-        let mut json = match self.from_reader_take::<JsonValue>() {
-            Ok(Some(json)) => json,
-            Ok(None) => {
-                return if self.events == 0 {
-                    Err(ApiError::NoData.into())
-                } else {
-                    Ok(Async::Ready(None))
-                };
-            }
-            Err(error) => {
-                emit!(SplunkHecRequestBodyInvalid {
-                    error: error.into()
-                });
-                return Err(ApiError::InvalidDataFormat { event: self.events }.into());
-            }
-        };
 
+    fn build_event(&mut self, mut json: JsonValue) -> Result<Event, Rejection> {
         // Construct Event from parsed json event
         let mut event = Event::new_empty_log();
         let log = event.as_mut_log();
@@ -486,7 +454,32 @@ impl<R: Read> Stream for EventStream<R> {
         emit!(SplunkHecEventReceived);
         self.events += 1;
 
-        Ok(Async::Ready(Some(event)))
+        Ok(event)
+    }
+}
+
+impl<R: Read> Iterator for EventIterator<R> {
+    type Item = Result<Event, Rejection>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.from_reader_take::<JsonValue>() {
+            Ok(Some(json)) => Some(self.build_event(json)),
+            Ok(None) => {
+                if self.events == 0 {
+                    Some(Err(ApiError::NoData.into()))
+                } else {
+                    None
+                }
+            }
+            Err(error) => {
+                emit!(SplunkHecRequestBodyInvalid {
+                    error: error.into()
+                });
+                Some(Err(
+                    ApiError::InvalidDataFormat { event: self.events }.into()
+                ))
+            }
+        }
     }
 }