feat http: add Restart HTTP handler

commit_hash:6fbd19ef34d6ecfb2675580d139306e75d6bdba9

.mapping.json

@@ -471,6 +471,8 @@
   "core/functional_tests/basic_chaos/tests-nonchaos/metrics/test_has_reopening_error_metric.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests-nonchaos/metrics/test_has_reopening_error_metric.py",
   "core/functional_tests/basic_chaos/tests-nonchaos/middlewares/test_testsuite_middleware.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests-nonchaos/middlewares/test_testsuite_middleware.py",
   "core/functional_tests/basic_chaos/tests-nonchaos/network/test_interfaces.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests-nonchaos/network/test_interfaces.py",
+  "core/functional_tests/basic_chaos/tests-restart/conftest.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests-restart/conftest.py",
+  "core/functional_tests/basic_chaos/tests-restart/test_restart.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests-restart/test_restart.py",
   "core/functional_tests/basic_chaos/tests/conftest.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests/conftest.py",
   "core/functional_tests/basic_chaos/tests/httpclient/conftest.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests/httpclient/conftest.py",
   "core/functional_tests/basic_chaos/tests/httpclient/test_httpclient.py":"taxi/uservices/userver/core/functional_tests/basic_chaos/tests/httpclient/test_httpclient.py",
@@ -799,6 +801,7 @@
   "core/include/userver/server/handlers/log_level.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/log_level.hpp",
   "core/include/userver/server/handlers/on_log_rotate.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/on_log_rotate.hpp",
   "core/include/userver/server/handlers/ping.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/ping.hpp",
+  "core/include/userver/server/handlers/restart.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/restart.hpp",
   "core/include/userver/server/handlers/server_monitor.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/server_monitor.hpp",
   "core/include/userver/server/handlers/tests_control.hpp":"taxi/uservices/userver/core/include/userver/server/handlers/tests_control.hpp",
   "core/include/userver/server/http/form_data_arg.hpp":"taxi/uservices/userver/core/include/userver/server/http/form_data_arg.hpp",
@@ -1468,6 +1471,7 @@
   "core/src/server/handlers/log_level.cpp":"taxi/uservices/userver/core/src/server/handlers/log_level.cpp",
   "core/src/server/handlers/on_log_rotate.cpp":"taxi/uservices/userver/core/src/server/handlers/on_log_rotate.cpp",
   "core/src/server/handlers/ping.cpp":"taxi/uservices/userver/core/src/server/handlers/ping.cpp",
+  "core/src/server/handlers/restart.cpp":"taxi/uservices/userver/core/src/server/handlers/restart.cpp",
   "core/src/server/handlers/server_monitor.cpp":"taxi/uservices/userver/core/src/server/handlers/server_monitor.cpp",
   "core/src/server/handlers/tests_control.cpp":"taxi/uservices/userver/core/src/server/handlers/tests_control.cpp",
   "core/src/server/http/create_parser_test.hpp":"taxi/uservices/userver/core/src/server/http/create_parser_test.hpp",

core/functional_tests/basic_chaos/service.cpp

@@ -8,6 +8,7 @@
 #include <userver/dynamic_config/updater/component.hpp>
 #include <userver/server/handlers/on_log_rotate.hpp>
 #include <userver/server/handlers/ping.hpp>
+#include <userver/server/handlers/restart.hpp>
 #include <userver/server/handlers/server_monitor.hpp>
 #include <userver/server/handlers/tests_control.hpp>
 #include <userver/utest/using_namespace_userver.hpp>
@@ -32,6 +33,7 @@ int main(int argc, char* argv[]) {
                                     .Append<server::handlers::TestsControl>()
                                     .Append<server::handlers::ServerMonitor>()
                                     .Append<server::handlers::Ping>()
+                                    .Append<server::handlers::Restart>()
                                     .Append<clients::dns::Component>()
                                     .Append<alerts::Handler>()
                                     .Append<components::DynamicConfigClient>()

core/functional_tests/basic_chaos/static_config.yaml

@@ -125,6 +125,11 @@ components_manager:
             throttling_enabled: false
             url_trailing_slash: strict-match
 
+        handler-restart:
+            path: /restart
+            method: GET
+            task_processor: main-task-processor
+
     task_processors:
         main-task-processor:
             worker_threads: 4

core/functional_tests/basic_chaos/tests-restart/conftest.py

@@ -0,0 +1 @@
+pytest_plugins = ['pytest_userver.plugins.core', 'pytest_userver.plugins']

core/functional_tests/basic_chaos/tests-restart/test_restart.py

@@ -0,0 +1,26 @@
+import asyncio
+import datetime
+
+
+async def wait_for_daemon_stop(_global_daemon_store):
+    deadline = datetime.datetime.now() + datetime.timedelta(seconds=10)
+    while (
+        datetime.datetime.now() < deadline
+        and _global_daemon_store.has_running_daemons()
+    ):
+        await asyncio.sleep(0.05)
+
+    assert (
+        not _global_daemon_store.has_running_daemons()
+    ), 'Daemon has not stopped'
+    await _global_daemon_store.aclose()
+
+
+async def test_restart(monitor_client, service_client, _global_daemon_store):
+    response = await monitor_client.get('/restart', params={'delay': '1'})
+    assert response.status == 200
+
+    response = await service_client.get('/ping')
+    assert response.status == 500
+
+    wait_for_daemon_stop(_global_daemon_store)

core/include/userver/components/run.hpp

@@ -52,6 +52,10 @@ void RunOnce(
 /// @see utils::DaemonMain
 void RunOnce(const InMemoryConfig& config, const ComponentList& component_list);
 
+/// Requests stop of the component system.
+/// The service will be eventually stopped.
+void RequestStop();
+
 namespace impl {
 
 // Composes a single static config schema from all components.

core/include/userver/server/handlers/restart.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+/// @file userver/server/handlers/restart.hpp
+/// @brief @copybrief server::handlers::Restart
+
+#include <atomic>
+
+#include <userver/server/handlers/http_handler_base.hpp>
+
+USERVER_NAMESPACE_BEGIN
+
+namespace server::handlers {
+
+// clang-format off
+
+/// @ingroup userver_components userver_http_handlers
+///
+/// @brief Handler that stops the service. It is expected that an external system
+/// (e.g. systemd or supervisord) restarts the service afterwards.
+///
+/// The handler uses monitor port.
+///
+/// The component has no service configuration except the
+/// @ref userver_http_handlers "common handler options".
+
+// clang-format on
+
+class Restart final : public HttpHandlerBase {
+public:
+    Restart(const components::ComponentConfig&, const components::ComponentContext&);
+
+    /// @ingroup userver_component_names
+    /// @brief The default name of server::handlers::Restart
+    static constexpr std::string_view kName = "handler-restart";
+
+    std::string HandleRequestThrow(const http::HttpRequest&, request::RequestContext&) const override;
+
+    components::ComponentHealth GetComponentHealth() const override;
+
+private:
+    mutable std::atomic<components::ComponentHealth> health_;
+};
+
+}  // namespace server::handlers
+
+USERVER_NAMESPACE_END

core/src/components/run.cpp

@@ -265,6 +265,8 @@ void RunOnce(const InMemoryConfig& config, const ComponentList& component_list)
     DoRun(config, {}, {}, component_list, RunMode::kOnce);
 }
 
+void RequestStop() { kill(getpid(), SIGTERM); }
+
 namespace impl {
 
 std::string GetStaticConfigSchema(const ComponentList& component_list) {

core/src/server/handlers/restart.cpp

@@ -0,0 +1,40 @@
+#include <userver/server/handlers/restart.hpp>
+
+#include <userver/components/run.hpp>
+#include <userver/engine/sleep.hpp>
+#include <userver/utils/async.hpp>
+#include <userver/utils/from_string.hpp>
+
+USERVER_NAMESPACE_BEGIN
+
+namespace server::handlers {
+
+namespace {
+constexpr std::string_view kDelay = "delay";
+constexpr std::chrono::seconds kDelayDefault{20};
+}  // namespace
+
+Restart::Restart(const components::ComponentConfig& config, const components::ComponentContext& context)
+    : HttpHandlerBase(config, context, true), health_{components::ComponentHealth::kOk} {}
+
+std::string Restart::HandleRequestThrow(const http::HttpRequest& request, request::RequestContext&) const {
+    auto delay = kDelayDefault;
+    if (request.HasArg(kDelay)) {
+        delay = std::chrono::seconds(utils::FromString<int>(request.GetArg(kDelay)));
+    }
+
+    health_ = components::ComponentHealth::kFatal;
+    engine::CriticalAsyncNoSpan([delay] {
+        engine::InterruptibleSleepFor(std::chrono::seconds(delay));
+        if (engine::current_task::ShouldCancel()) return;
+        components::RequestStop();
+    }).Detach();
+
+    return "OK";
+}
+
+components::ComponentHealth Restart::GetComponentHealth() const { return health_; }
+
+}  // namespace server::handlers
+
+USERVER_NAMESPACE_END