make h2 client connection cancellable

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/bin/proxmox-backup-client.rs

@@ -476,6 +476,7 @@ fn create_backup(
     }
 
     client.finish().wait()?;
+    client.force_close();
 
     let end_time = Local.timestamp(Local::now().timestamp(), 0);
     let elapsed = end_time.signed_duration_since(backup_time);

src/client/http_client.rs

@@ -20,6 +20,7 @@ use serde_json::{json, Value};
 use url::percent_encoding::{percent_encode,  DEFAULT_ENCODE_SET};
 
 use crate::tools::{self, BroadcastFuture, tty};
+use crate::tools::futures::{cancellable, Canceller};
 use super::pipe_to_stream::*;
 use super::merge_known_chunks::*;
 
@@ -291,14 +292,21 @@ impl HttpClient {
                     let connection = connection
                         .map_err(|_| panic!("HTTP/2.0 connection failed"));
 
+                    let (connection, canceller) = cancellable(connection)?;
+                    // A cancellable future returns an Option which is None when cancelled and
+                    // Some when it finished instead, since we don't care about the return type we
+                    // need to map it away:
+                    let connection = connection.map(|_| ());
+
                     // Spawn a new task to drive the connection state
                     hyper::rt::spawn(connection);
 
                     // Wait until the `SendRequest` handle has available capacity.
-                    h2.ready()
-                        .map(BackupClient::new)
-                        .map_err(Error::from)
+                    Ok(h2.ready()
+                        .map(move |c| BackupClient::new(c, canceller))
+                        .map_err(Error::from))
                 })
+                .flatten()
         })
     }
 
@@ -407,13 +415,21 @@ impl HttpClient {
 //#[derive(Clone)]
 pub struct BackupClient {
     h2: H2Client,
+    canceller: Option<Canceller>,
 }
 
 
 impl BackupClient {
 
-    pub fn new(h2: h2::client::SendRequest<bytes::Bytes>) -> Self {
-        Self { h2: H2Client::new(h2) }
+    pub fn new(h2: h2::client::SendRequest<bytes::Bytes>, canceller: Canceller) -> Self {
+        Self {
+            h2: H2Client::new(h2),
+            canceller: Some(canceller),
+        }
+    }
+
+    pub fn force_close(mut self) {
+        self.canceller.take().unwrap().cancel();
     }
 
     pub fn get(&self, path: &str, param: Option<Value>) -> impl Future<Item=Value, Error=Error> {