fix(remote): surface HTTP and registry errors

- Map HTTP 404 to RemoteError::NotFound; propagate other HTTP errors\n- Fail push when the remote registry payload is invalid

crates/karapace-remote/src/http.rs

@@ -56,7 +56,28 @@ impl HttpBackend {
         if let Some(ref token) = self.config.auth_token {
             req = req.header("Authorization", &format!("Bearer {token}"));
         }
-        let resp = req.call().map_err(|e| RemoteError::Http(e.to_string()))?;
+        let resp = match req.call() {
+            Ok(r) => r,
+            Err(ureq::Error::StatusCode(404)) => {
+                return Err(RemoteError::NotFound(url.to_owned()));
+            }
+            Err(ureq::Error::StatusCode(code)) => {
+                return Err(RemoteError::Http(format!("HTTP {code} for {url}")));
+            }
+            Err(e) => {
+                return Err(RemoteError::Http(e.to_string()));
+            }
+        };
+
+        let status = resp.status();
+        let code = status.as_u16();
+        if code == 404 {
+            return Err(RemoteError::NotFound(url.to_owned()));
+        }
+        if code >= 400 {
+            return Err(RemoteError::Http(format!("HTTP {code} for {url}")));
+        }
+
         let mut reader = resp.into_body().into_reader();
         let mut body = Vec::new();
         reader
@@ -73,8 +94,11 @@ impl HttpBackend {
         if let Some(ref token) = self.config.auth_token {
             req = req.header("Authorization", &format!("Bearer {token}"));
         }
-        let resp = req.call().map_err(|e| RemoteError::Http(e.to_string()))?;
-        Ok(resp.status().into())
+        match req.call() {
+            Ok(resp) => Ok(resp.status().into()),
+            Err(ureq::Error::StatusCode(code)) => Ok(code),
+            Err(e) => Err(RemoteError::Http(e.to_string())),
+        }
     }
 }
 
@@ -94,9 +118,10 @@ impl RemoteBackend for HttpBackend {
     fn has_blob(&self, kind: BlobKind, key: &str) -> Result<bool, RemoteError> {
         let url = self.url(kind, key);
         tracing::debug!("HEAD {url}");
-        match self.do_head(&url) {
-            Ok(status) => Ok(status == 200),
-            Err(_) => Ok(false),
+        match self.do_head(&url)? {
+            200 => Ok(true),
+            404 => Ok(false),
+            code => Err(RemoteError::Http(format!("HTTP {code} for HEAD {url}"))),
         }
     }
 

crates/karapace-remote/src/transfer.rs

@@ -86,8 +86,9 @@ pub fn push_env(
     // 7. Update registry if key provided
     if let Some(key) = registry_key {
         let mut registry = match backend.get_registry() {
-            Ok(data) => Registry::from_bytes(&data).unwrap_or_default(),
-            Err(_) => Registry::new(),
+            Ok(data) => Registry::from_bytes(&data)?,
+            Err(RemoteError::NotFound(_)) => Registry::new(),
+            Err(e) => return Err(e),
         };
         registry.publish(
             key,