Merge 'Sanitize /system/highest_supported_sstable_version API endpoin…

…t' from Pavel Emelyanov

Its handler dereferences long chain of objects to get to the value it needs. There's shorter way.
Also, the endpoint in question is not unregistered on stop.

Closes scylladb#21279

* github.com:scylladb/scylladb:
  api: Make get_highest_supported_sstable_version use proper service
  api: Move system::get_highest_supported_sstable_version set/unset
  api: Scaffold for sstables-format-selector

api/api.cc

@@ -135,6 +135,14 @@ future<> unset_load_meter(http_context& ctx) {
     return ctx.http_server.set_routes([&ctx] (routes& r) { unset_load_meter(ctx, r); });
 }
 
+future<> set_format_selector(http_context& ctx, db::sstables_format_selector& sel) {
+    return ctx.http_server.set_routes([&ctx, &sel] (routes& r) { set_format_selector(ctx, r, sel); });
+}
+
+future<> unset_format_selector(http_context& ctx) {
+    return ctx.http_server.set_routes([&ctx] (routes& r) { unset_format_selector(ctx, r); });
+}
+
 future<> set_server_sstables_loader(http_context& ctx, sharded<sstables_loader>& sst_loader) {
     return ctx.http_server.set_routes([&ctx, &sst_loader] (routes& r) { set_sstables_loader(ctx, r, sst_loader); });
 }

api/api_init.hh

@@ -51,6 +51,7 @@ namespace cql_transport { class controller; }
 namespace db {
 class snapshot_ctl;
 class config;
+class sstables_format_selector;
 namespace view {
 class view_builder;
 }
@@ -135,6 +136,8 @@ future<> set_server_raft(http_context&, sharded<service::raft_group_registry>&);
 future<> unset_server_raft(http_context&);
 future<> set_load_meter(http_context& ctx, service::load_meter& lm);
 future<> unset_load_meter(http_context& ctx);
+future<> set_format_selector(http_context& ctx, db::sstables_format_selector& sel);
+future<> unset_format_selector(http_context& ctx);
 future<> set_server_cql_server_test(http_context& ctx, cql_transport::controller& ctl);
 future<> unset_server_cql_server_test(http_context& ctx);
 future<> set_server_commitlog(http_context& ctx, sharded<replica::database>&);

api/system.cc

@@ -10,7 +10,7 @@
 #include "api/api-doc/system.json.hh"
 #include "api/api-doc/metrics.json.hh"
 #include "replica/database.hh"
-#include "sstables/sstables_manager.hh"
+#include "db/sstables-format-selector.hh"
 
 #include <rapidjson/document.h>
 #include <seastar/core/reactor.hh>
@@ -183,11 +183,18 @@ void set_system(http_context& ctx, routes& r) {
         apilog.info("Profile dumped to {}", profile_dest);
         return make_ready_future<json::json_return_type>(json::json_return_type(json::json_void()));
     }) ;
+}
 
-    hs::get_highest_supported_sstable_version.set(r, [&ctx] (const_req req) {
-        auto& table = ctx.db.local().find_column_family("system", "local");
-        return seastar::to_sstring(table.get_sstables_manager().get_highest_supported_format());
+void set_format_selector(http_context& ctx, routes& r, db::sstables_format_selector& sel) {
+    hs::get_highest_supported_sstable_version.set(r, [&sel] (std::unique_ptr<request> req) {
+        return smp::submit_to(0, [&sel] {
+            return make_ready_future<json::json_return_type>(seastar::to_sstring(sel.selected_format()));
+        });
     });
 }
 
+void unset_format_selector(http_context& ctx, routes& r) {
+    hs::get_highest_supported_sstable_version.unset(r);
+}
+
 }

api/system.hh

@@ -12,9 +12,14 @@ namespace seastar::httpd {
 class routes;
 }
 
+namespace db { class sstables_format_selector; }
+
 namespace api {
 
 struct http_context;
 void set_system(http_context& ctx, seastar::httpd::routes& r);
 
+void set_format_selector(http_context& ctx, seastar::httpd::routes& r, db::sstables_format_selector& sel);
+void unset_format_selector(http_context& ctx, seastar::httpd::routes& r);
+
 }

main.cc

@@ -1268,6 +1268,11 @@ To start the scylla server proper, simply invoke as: scylla server (or just scyl
 
             db::sstables_format_selector sst_format_selector(db);
 
+            api::set_format_selector(ctx, sst_format_selector).get();
+            auto stop_format_seletor_api = defer_verbose_shutdown("sstables format selector API", [&ctx] {
+                api::unset_format_selector(ctx).get();
+            });
+
             supervisor::notify("starting system keyspace");
             sys_ks.start(std::ref(qp), std::ref(db)).get();
             // TODO: stop()?