[pbs-devel] [PATCH proxmox v4 3/4] s3 client: implement list buckets method

[Christian Ebner]

Extends the client by the list buckets method which allows to
fetch the buckets owned by the user with who's access key the
request is signed.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
Reviewed-by: Lukas Wagner <l.wagner at proxmox.com>
Tested-by: Lukas Wagner <l.wagner at proxmox.com>
---
changes since version 3:
- added missing doc comments
- refactored response parsing as suggested

 proxmox-s3-client/src/client.rs          | 14 +++++-
 proxmox-s3-client/src/response_reader.rs | 61 ++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/proxmox-s3-client/src/client.rs b/proxmox-s3-client/src/client.rs
index 5c07671c..ae61c590 100644
--- a/proxmox-s3-client/src/client.rs
+++ b/proxmox-s3-client/src/client.rs
@@ -28,7 +28,7 @@ use crate::aws_sign_v4::{aws_sign_v4_signature, aws_sign_v4_uri_encode};
 use crate::object_key::S3ObjectKey;
 use crate::response_reader::{
     CopyObjectResponse, DeleteObjectsResponse, GetObjectResponse, HeadObjectResponse,
-    ListObjectsV2Response, PutObjectResponse, ResponseReader,
+    ListBucketsResponse, ListObjectsV2Response, PutObjectResponse, ResponseReader,
 };
 
 const S3_HTTP_CONNECT_TIMEOUT: Duration = Duration::from_secs(10);
@@ -318,6 +318,18 @@ impl S3Client {
         Ok(())
     }
 
+    /// List all buckets owned by the user authenticated via the access key.
+    /// See reference docs: https://docs.aws.amazon.com/AmazonS3/latest/API/API_ListBuckets.html
+    pub async fn list_buckets(&self) -> Result<ListBucketsResponse, Error> {
+        let request = Request::builder()
+            .method(Method::GET)
+            .uri(self.build_uri("/", &[])?)
+            .body(Body::empty())?;
+        let response = self.send(request).await?;
+        let response_reader = ResponseReader::new(response);
+        response_reader.list_buckets_response().await
+    }
+
     /// Fetch metadata from an object without returning the object itself.
     /// See reference docs: https://docs.aws.amazon.com/AmazonS3/latest/API/API_HeadObject.html
     pub async fn head_object(
diff --git a/proxmox-s3-client/src/response_reader.rs b/proxmox-s3-client/src/response_reader.rs
index a7c71639..79a61cea 100644
--- a/proxmox-s3-client/src/response_reader.rs
+++ b/proxmox-s3-client/src/response_reader.rs
@@ -153,6 +153,44 @@ pub struct CopyObjectResult {
     pub last_modified: LastModifiedTimestamp,
 }
 
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "PascalCase")]
+/// Parsed response of the list buckets api call
+pub struct ListBucketsResponse {
+    /// List of buckets
+    pub buckets: Vec<Bucket>,
+}
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "PascalCase")]
+/// Subset of the list buckets response used to deserialize the buckets tag.
+/// https://docs.aws.amazon.com/AmazonS3/latest/API/API_ListBuckets.html#API_ListBuckets_ResponseElements
+pub struct ListAllMyBucketsResult {
+    /// Buckets field.
+    pub buckets: Option<Buckets>,
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "PascalCase")]
+/// Subset used to deserialize the list of bucket tags in list buckets response.
+pub struct Buckets {
+    /// List of buckets.
+    pub bucket: Vec<Bucket>,
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "PascalCase")]
+/// Subset used to deserialize bucket tag contents in the list buckets response.
+pub struct Bucket {
+    /// Bucket name.
+    pub name: String,
+    /// Bucket ARN.
+    pub bucket_arn: Option<String>,
+    /// Bucket region.
+    pub bucket_region: Option<String>,
+    /// Bucket creation date.
+    pub creation_date: LastModifiedTimestamp,
+}
+
 impl ResponseReader {
     pub(crate) fn new(response: Response<Incoming>) -> Self {
         Self { response }
@@ -339,6 +377,29 @@ impl ResponseReader {
         })
     }
 
+    /// Response parser for list buckets api calls.
+    pub(crate) async fn list_buckets_response(self) -> Result<ListBucketsResponse, Error> {
+        let (parts, body) = self.response.into_parts();
+        let body = body.collect().await?.to_bytes();
+
+        if !matches!(parts.status, StatusCode::OK) {
+            Self::log_error_response_utf8(body);
+            bail!("unexpected status code {}", parts.status);
+        };
+
+        let body = String::from_utf8(body.to_vec())?;
+
+        let list_buckets_result: ListAllMyBucketsResult =
+            serde_xml_rs::from_str(&body).context("failed to parse response body")?;
+
+        let buckets = list_buckets_result
+            .buckets
+            .map(|b| b.bucket)
+            .unwrap_or_default();
+
+        Ok(ListBucketsResponse { buckets })
+    }
+
     fn log_error_response_utf8(body: Bytes) {
         if let Ok(body) = String::from_utf8(body.to_vec()) {
             if !body.is_empty() {
-- 
2.47.2