Add /version endpoint

This endpoint allows clients to check the version of the VSS API that
the server is serving.

It also serves as a health check.

Author: tankyleo

.github/workflows/build-and-deploy-rust.yml

@@ -45,6 +45,8 @@ jobs:
         run: |
           sleep 5
 
+          [[ $(curl -f -s http://localhost:8080/vss/version | xxd -p) == "0801" ]] || { echo "Version check failed"; exit 1; }
+
           # Put request with store='storeId' and key=k1
           hex=0A0773746F726549641A150A026B3110FFFFFFFFFFFFFFFFFF011A046B317631
           curl -f --data-binary "$(echo "$hex" | xxd -r -p)" http://localhost:8080/vss/putObjects

proto/vss.proto

@@ -3,6 +3,23 @@ package vss;
 option java_multiple_files = true;
 option java_package = "org.vss";
 
+// Server response on the `/version` endpoint.
+message VersionResponse {
+
+  // The API version supported by the server.
+  Version version = 1;
+}
+
+// Versions of the VSS API.
+enum Version {
+
+  // Default protobuf Enum value. Will not be used as `Version` by server.
+  VUNKNOWN = 0;
+
+  // The initial version of the VSS API.
+  V1 = 1;
+}
+
 // Request payload to be used for `GetObject` API call to server.
 message GetObjectRequest {
 

rust/api/src/types.rs

@@ -1,3 +1,11 @@
+/// Server response on the `/version` endpoint.
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct VersionResponse {
+    /// The API version supported by the server.
+    #[prost(enumeration = "Version", tag = "1")]
+    pub version: i32,
+}
 /// Request payload to be used for `GetObject` API call to server.
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
@@ -331,6 +339,35 @@ pub struct PlaintextBlob {
     #[prost(int64, tag = "2")]
     pub version: i64,
 }
+/// Versions of the VSS API.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
+#[repr(i32)]
+pub enum Version {
+    /// Default protobuf Enum value. Will not be used as `Version` by server.
+    Vunknown = 0,
+    /// The initial version of the VSS API.
+    V1 = 1,
+}
+impl Version {
+    /// String value of the enum field names used in the ProtoBuf definition.
+    ///
+    /// The values are not transformed in any way and thus are considered stable
+    /// (if the ProtoBuf definition does not change) and safe for programmatic use.
+    pub fn as_str_name(&self) -> &'static str {
+        match self {
+            Version::Vunknown => "VUNKNOWN",
+            Version::V1 => "V1",
+        }
+    }
+    /// Creates an enum from field names used in the ProtoBuf definition.
+    pub fn from_str_name(value: &str) -> ::core::option::Option<Self> {
+        match value {
+            "VUNKNOWN" => Some(Self::Vunknown),
+            "V1" => Some(Self::V1),
+            _ => None,
+        }
+    }
+}
 /// ErrorCodes to be used in `ErrorResponse`
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, ::prost::Enumeration)]
 #[repr(i32)]

rust/server/src/vss_service.rs

@@ -12,7 +12,7 @@ use api::kv_store::KvStore;
 use api::types::{
 	DeleteObjectRequest, DeleteObjectResponse, ErrorCode, ErrorResponse, GetObjectRequest,
 	GetObjectResponse, ListKeyVersionsRequest, ListKeyVersionsResponse, PutObjectRequest,
-	PutObjectResponse,
+	PutObjectResponse, Version, VersionResponse,
 };
 use std::future::Future;
 use std::pin::Pin;
@@ -80,6 +80,14 @@ impl Service<Request<Incoming>> for VssService {
 			let prefix_stripped_path = path.strip_prefix(BASE_PATH_PREFIX).unwrap_or_default();
 
 			match prefix_stripped_path {
+				"/version" => {
+					let response = VersionResponse { version: Version::V1.into() };
+					let response = Response::builder()
+						.body(Full::new(Bytes::from(response.encode_to_vec())))
+						// unwrap safety: body only errors when previous chained calls failed.
+						.unwrap();
+					Ok(response)
+				},
 				"/getObject" => {
 					handle_request(
 						store,