[v22.1.x] Schema Registry and REST Proxy: health checks

src/v/pandaproxy/api/api-doc/rest.json

@@ -547,4 +547,18 @@
           }
         }
       }
+    },
+    "/status/ready": {
+      "get": {
+        "summary": "Health check",
+        "operationId": "http_rest_status_ready",
+        "responses": {
+          "200": {
+            "description": "Success"
+          },
+          "503": {
+            "description": "Service Unavailable"
+          }
+        }
+      }
     }

src/v/pandaproxy/api/api-doc/schema_registry.json

@@ -848,4 +848,18 @@
           }
         }
       }
+    },
+    "/status/ready": {
+      "get": {
+        "summary": "Health check",
+        "operationId": "schema_registry_status_ready",
+        "responses": {
+          "200": {
+            "description": "Success"
+          },
+          "503": {
+            "description": "Service Unavailable"
+          }
+        }
+      }
     }

src/v/pandaproxy/rest/handlers.cc

@@ -523,4 +523,15 @@ post_consumer_offsets(server::request_t rq, server::reply_t rp) {
       group_shard, rq.context().smp_sg, std::move(handler));
 }
 
+ss::future<proxy::server::reply_t>
+status_ready(proxy::server::request_t rq, proxy::server::reply_t rp) {
+    auto make_metadata_req = []() {
+        return kafka::metadata_request{.list_all_topics = false};
+    };
+
+    auto res = co_await rq.dispatch(make_metadata_req);
+    rp.rep->set_status(ss::httpd::reply::status_type::ok);
+    co_return rp;
+}
+
 } // namespace pandaproxy::rest

src/v/pandaproxy/rest/handlers.h

@@ -49,4 +49,7 @@ ss::future<ctx_server<proxy>::reply_t> get_consumer_offsets(
 ss::future<ctx_server<proxy>::reply_t> post_consumer_offsets(
   ctx_server<proxy>::request_t rq, ctx_server<proxy>::reply_t rp);
 
+ss::future<proxy::server::reply_t>
+status_ready(proxy::server::request_t rq, proxy::server::reply_t rp);
+
 } // namespace pandaproxy::rest

src/v/pandaproxy/rest/proxy.cc

@@ -56,6 +56,10 @@ server::routes_t get_proxy_routes() {
     routes.routes.emplace_back(server::route_t{
       ss::httpd::rest_json::post_consumer_offsets, post_consumer_offsets});
 
+    routes.routes.emplace_back(server::route_t{
+      ss::httpd::rest_json::http_rest_status_ready,
+      wrap(gate, es, status_ready)});
+
     return routes;
 }
 

src/v/pandaproxy/schema_registry/handlers.cc

@@ -516,4 +516,11 @@ compatibility_subject_version(server::request_t rq, server::reply_t rp) {
     co_return rp;
 }
 
+ss::future<server::reply_t>
+status_ready(server::request_t rq, server::reply_t rp) {
+    co_await rq.service().writer().read_sync();
+    rp.rep->set_status(ss::httpd::reply::status_type::ok);
+    co_return rp;
+}
+
 } // namespace pandaproxy::schema_registry

src/v/pandaproxy/schema_registry/handlers.h

@@ -74,4 +74,7 @@ ss::future<ctx_server<service>::reply_t> delete_subject_version(
 ss::future<ctx_server<service>::reply_t> compatibility_subject_version(
   ctx_server<service>::request_t rq, ctx_server<service>::reply_t rp);
 
+ss::future<ctx_server<service>::reply_t> status_ready(
+  ctx_server<service>::request_t rq, ctx_server<service>::reply_t rp);
+
 } // namespace pandaproxy::schema_registry

src/v/pandaproxy/schema_registry/service.cc

@@ -130,6 +130,10 @@ server::routes_t get_schema_registry_routes(ss::gate& gate, one_shot& es) {
       ss::httpd::schema_registry_json::compatibility_subject_version,
       wrap(gate, es, compatibility_subject_version)});
 
+    routes.routes.emplace_back(server::route_t{
+      ss::httpd::schema_registry_json::schema_registry_status_ready,
+      wrap(gate, es, status_ready)});
+
     return routes;
 }