Add event loop application starter
New application starter reads a configuration file with the list of
applications and their properties (arguments, binary name, etc.) and
manages starting and restarting them. The status of applications are
reported on an event loop channel and they can be controlled with a
separate starter_cmd tool.
Change-Id: I7691840be38dc28887e48efcdff7926590710eb7
diff --git a/aos/starter/starter_rpc_lib.cc b/aos/starter/starter_rpc_lib.cc
new file mode 100644
index 0000000..efb4042
--- /dev/null
+++ b/aos/starter/starter_rpc_lib.cc
@@ -0,0 +1,131 @@
+#include "starter_rpc_lib.h"
+
+#include "aos/events/shm_event_loop.h"
+#include "aos/flatbuffer_merge.h"
+
+namespace aos {
+namespace starter {
+
+const aos::starter::ApplicationStatus *FindApplicationStatus(
+ const aos::starter::Status &status, std::string_view name) {
+ if (!status.has_statuses()) {
+ return nullptr;
+ }
+
+ auto statuses = status.statuses();
+
+ auto search =
+ std::find_if(statuses->begin(), statuses->end(),
+ [name](const aos::starter::ApplicationStatus *app_status) {
+ return app_status->has_name() &&
+ app_status->name()->string_view() == name;
+ });
+ if (search == statuses->end()) {
+ return nullptr;
+ }
+ return *search;
+}
+
+bool SendCommandBlocking(aos::starter::Command command, std::string_view name,
+ const aos::Configuration *config,
+ std::chrono::milliseconds timeout) {
+ aos::ShmEventLoop event_loop(config);
+ event_loop.SkipAosLog();
+
+ ::aos::Sender<aos::starter::StarterRpc> cmd_sender =
+ event_loop.MakeSender<aos::starter::StarterRpc>("/aos");
+
+ // Wait until event loop starts to send command so watcher is ready
+ event_loop.OnRun([&cmd_sender, command, name] {
+ aos::Sender<aos::starter::StarterRpc>::Builder builder =
+ cmd_sender.MakeBuilder();
+
+ auto name_str = builder.fbb()->CreateString(name);
+
+ aos::starter::StarterRpc::Builder cmd_builder =
+ builder.MakeBuilder<aos::starter::StarterRpc>();
+
+ cmd_builder.add_name(name_str);
+ cmd_builder.add_command(command);
+
+ builder.Send(cmd_builder.Finish());
+ });
+
+ // If still waiting after timeout milliseconds, exit the loop
+ event_loop.AddTimer([&event_loop] { event_loop.Exit(); })
+ ->Setup(event_loop.monotonic_now() + timeout);
+
+ // Fetch the last list of statuses to compare the requested application's id
+ // against for commands such as restart.
+ auto initial_status_fetcher =
+ event_loop.MakeFetcher<aos::starter::Status>("/aos");
+ initial_status_fetcher.Fetch();
+ auto initial_status =
+ initial_status_fetcher
+ ? FindApplicationStatus(*initial_status_fetcher, name)
+ : nullptr;
+
+ const std::optional<uint64_t> initial_id =
+ (initial_status != nullptr && initial_status->has_id())
+ ? std::make_optional(initial_status->id())
+ : std::nullopt;
+
+ bool success = false;
+ event_loop.MakeWatcher(
+ "/aos", [&event_loop, command, name, initial_id,
+ &success](const aos::starter::Status &status) {
+ const aos::starter::ApplicationStatus *app_status =
+ FindApplicationStatus(status, name);
+
+ const std::optional<aos::starter::State> state =
+ (app_status != nullptr && app_status->has_state())
+ ? std::make_optional(app_status->state())
+ : std::nullopt;
+
+ switch (command) {
+ case aos::starter::Command::START: {
+ if (state == aos::starter::State::RUNNING) {
+ success = true;
+ event_loop.Exit();
+ }
+ break;
+ }
+ case aos::starter::Command::STOP: {
+ if (state == aos::starter::State::STOPPED) {
+ success = true;
+ event_loop.Exit();
+ }
+ break;
+ }
+ case aos::starter::Command::RESTART: {
+ if (state == aos::starter::State::RUNNING && app_status->has_id() &&
+ app_status->id() != initial_id) {
+ success = true;
+ event_loop.Exit();
+ }
+ break;
+ }
+ }
+ });
+
+ event_loop.Run();
+
+ return success;
+}
+
+const FlatbufferDetachedBuffer<aos::starter::ApplicationStatus> GetStatus(
+ std::string_view name, const Configuration *config) {
+ ShmEventLoop event_loop(config);
+ event_loop.SkipAosLog();
+
+ auto status_fetcher = event_loop.MakeFetcher<aos::starter::Status>("/aos");
+ status_fetcher.Fetch();
+ auto status =
+ status_fetcher ? FindApplicationStatus(*status_fetcher, name) : nullptr;
+ return status ? aos::CopyFlatBuffer(status)
+ : FlatbufferDetachedBuffer<
+ aos::starter::ApplicationStatus>::Empty();
+}
+
+} // namespace starter
+} // namespace aos