huskies: merge 1173 story Identity-aware fleet checks: cryptographic node identity in upgrade and health probes

server/src/service/gateway/io.rs

@@ -94,6 +94,32 @@ pub fn write_bot_config(config_dir: &Path, content: &str) -> Result<(), String>
     std::fs::write(&path, content).map_err(|e| format!("cannot write bot.toml: {e}"))
 }
 
+// ── Identity probe I/O ───────────────────────────────────────────────────────
+
+/// `GET {sled_url}/identity?nonce=<nonce>` and parse the JSON body.
+///
+/// Returns `None` when the sled is unreachable or the response body doesn't
+/// parse as [`super::identity::IdentityProbeResponse`] — callers treat that
+/// the same as an unverifiable identity (distinct from a legacy sled, which
+/// responds but omits the `signature` field).
+pub async fn probe_identity(
+    client: &Client,
+    sled_url: &str,
+    nonce: &str,
+) -> Option<super::identity::IdentityProbeResponse> {
+    // `nonce` is always a hex string (see `node_identity::generate_challenge`),
+    // so no percent-encoding is needed for safe inclusion in the query string.
+    let url = format!("{}/identity?nonce={nonce}", sled_url.trim_end_matches('/'));
+    client
+        .get(&url)
+        .send()
+        .await
+        .ok()?
+        .json::<super::identity::IdentityProbeResponse>()
+        .await
+        .ok()
+}
+
 // ── MCP proxy I/O ───────────────────────────────────────────────────────────
 
 /// Proxy a raw MCP request body to the given project URL.