Make the result stream of Images::build continuous (#134)

Currently, when the `Images::build` endpoint is called, no continuous
stream is returned: once an image is successfully built, a single
`ImageBuildLibpod200Response` is returned with the entire output of the
build process.

This is especially bad for user interfaces, as no feedback can be
provided to the user.

To make the stream continuous, the implementation of the endpoint is
rewritten. Here, the implementation of the endpoint `Images::pull` is
used as a template.

src/api/images.rs

@@ -5,7 +5,6 @@ use crate::{
 };
 
 use containers_api::{tarball, url};
-use futures_util::future::TryFutureExt;
 use futures_util::stream::{Stream, TryStreamExt};
 
 impl_api_ty!(
@@ -355,37 +354,43 @@ impl Images {
     ///     let opts = ImageBuildOpts::builder("http://some.url.to/Dockerfile")
     ///             .tag("myimage:1.0.0")
     ///             .build();
-    ///     let images = podman.images();
-    ///     let mut build_stream = images.build(&opts);
     ///
-    ///     while let Some(chunk) = build_stream.next().await {
-    ///         match chunk {
-    ///             Ok(chunk) => println!("{:?}", chunk),
-    ///             Err(e) => eprintln!("{}", e),
-    ///         }
-    ///     }
+    ///     let images = podman.images();
+    ///     match images.build(&opts) {
+    ///         Ok(mut build_stream) => while let Some(chunk) = build_stream.next().await {
+    ///             match chunk {
+    ///                 Ok(chunk) => println!("{:?}", chunk),
+    ///                 Err(e) => eprintln!("{}", e),
+    ///             }
+    ///         },
+    ///         Err(e) => eprintln!("{}", e),
+    ///     };
     /// };
     /// ```
     |
-    pub fn build<'podman>(
-        &'podman self,
-        opts: &'podman opts::ImageBuildOpts,
-    ) -> impl Stream <Item = Result<models::ImageBuildLibpod200Response>> + Unpin + 'podman {
-        let ep = url::construct_ep("/libpod/build", opts.serialize());
+    pub fn build(
+        &self,
+        opts: &opts::ImageBuildOpts,
+    ) -> Result<impl Stream <Item = Result<models::ImageBuildLibpod200Response>> + Unpin + '_> {
         let mut bytes = Vec::default();
+        let path = opts.get_param("path").ok_or_else(|| Error::OptsSerialization("expected a path to build context".into()))?;
+        tarball::dir(&mut bytes, &path)?;
 
-        Box::pin(
-            async move {
-                let path = opts.get_param("path").ok_or_else(|| Error::OptsSerialization("expected a path to build context".into()))?;
-                tarball::dir(&mut bytes, &path)?;
-
-                let value_stream =
-                    self.podman.stream_post_into(ep, Payload::Tar(bytes), Headers::none());
-
-                Ok(value_stream)
-            }
-            .try_flatten_stream(),
+        let ep = url::construct_ep("/libpod/build", opts.serialize());
+        let reader = Box::pin(
+            self.podman
+                .stream_post(ep, Payload::Tar(bytes), Headers::none())
+                .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e)),
         )
+        .into_async_read();
+
+        Ok(Box::pin(
+            futures_codec::FramedRead::new(reader, futures_codec::LinesCodec)
+                .map_err(Error::IO)
+                .and_then(|s: String| async move {
+                    serde_json::from_str(&s).map_err(Error::SerdeJsonError)
+                }),
+        ))
     }}
 
     api_doc! {