feat: add http client to download piece (#51)

Signed-off-by: Gaius <gaius.qi@gmail.com>

Cargo.toml

@@ -41,7 +41,9 @@ opentelemetry-jaeger = { version = "0.17.0", features = ["rt-tokio"] }
 lazy_static = "1.4"
 prometheus = "0.13.3"
 warp = "0.3.5"
+reqwest = "0.11.18"
 tokio = { version = "1.28.1", features = ["full"] }
+bytes = "1.4"
 hostname = "^0.3"
 local-ip-address = "0.5.3"
 rocksdb = "0.21.0"

src/backend/http.rs

@@ -0,0 +1,60 @@
+/*
+ *     Copyright 2023 The Dragonfly Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use bytes::Bytes;
+use reqwest::header::HeaderMap;
+use std::time::Duration;
+
+// Request is the request for HTTP backend.
+pub struct Request {
+    // url is the url of the request.
+    pub url: String,
+    // header is the headers of the request.
+    pub header: HeaderMap,
+    // timeout is the timeout of the request.
+    pub timeout: Option<Duration>,
+}
+
+// Response is the response for HTTP backend.
+pub struct Response {
+    // header is the headers of the response.
+    pub header: HeaderMap,
+    // status_code is the status code of the response.
+    pub status_code: reqwest::StatusCode,
+    // body is the content of the response.
+    pub body: Bytes,
+}
+
+// HTTP is the HTTP backend.
+pub struct HTTP {}
+
+// HTTP implements the http interface.
+impl HTTP {
+    // Get gets the content of the request.
+    pub async fn get(&self, req: Request) -> super::Result<Response> {
+        let mut request_builder = reqwest::Client::new().get(&req.url).headers(req.header);
+        if let Some(timeout) = req.timeout {
+            request_builder = request_builder.timeout(timeout);
+        }
+
+        let response = request_builder.send().await?;
+        Ok(Response {
+            header: response.headers().clone(),
+            status_code: response.status(),
+            body: response.bytes().await?,
+        })
+    }
+}

src/backend/mod.rs

@@ -13,3 +13,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+pub mod http;
+
+// Error is the error for Backend.
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+    // Reqwest is the error for reqwest.
+    #[error(transparent)]
+    Reqwest(#[from] reqwest::Error),
+}
+
+// Result is the result for Backend.
+pub type Result<T> = std::result::Result<T, Error>;