buffet: Allow configurable polling period

While here, switch to using a repeating timer, which is cleaner.

BUG=brillo:564,brillo:522
TEST=buffet_Registration passes.  Can touch the polling period config
flag and see that polling period changes.

Change-Id: I8d0cca5d38e8ba91dad1a97311cc20603e300654
Reviewed-on: https://chromium-review.googlesource.com/260920
Tested-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>

buffet/buffet_config.cc

diff --git a/buffet/buffet_config.cc b/buffet/buffet_config.cc
index 36acee9..e4f6209 100644
--- a/buffet/buffet_config.cc
+++ b/buffet/buffet_config.cc
@@ -4,6 +4,9 @@
 
 #include "buffet/buffet_config.h"
 
+#include <base/logging.h>
+#include <base/strings/string_number_conversions.h>
+
 namespace buffet {
 namespace config_keys {
 
@@ -18,6 +21,7 @@
 const char kDefaultDescription[]   = "default_description";
 const char kDefaultLocation[]      = "default_location";
 const char kModelId[]              = "model_id";
+const char kPollingPeriodMs[]      = "polling_period_ms";
 
 }  // namespace config_keys
 
@@ -40,6 +44,13 @@
   store.GetString(config_keys::kDefaultDescription, &default_description_);
   store.GetString(config_keys::kDefaultLocation, &default_location_);
   store.GetString(config_keys::kModelId, &model_id_);
+  std::string polling_period_str;
+  if (store.GetString(config_keys::kPollingPeriodMs, &polling_period_str)) {
+    CHECK(base::StringToUint64(polling_period_str, &polling_period_ms_))
+        << "Failed to parse polling period in configuration file.";
+    VLOG(1) << "Using a polling period of " << polling_period_ms_
+            << " milliseconds.";
+  }
 }
 
 }  // namespace buffet

buffet/buffet_config.h

diff --git a/buffet/buffet_config.h b/buffet/buffet_config.h
index 539191e..550f0da 100644
--- a/buffet/buffet_config.h
+++ b/buffet/buffet_config.h
@@ -30,6 +30,7 @@
   std::string default_description() const { return default_description_; }
   std::string default_location() const { return default_location_; }
   std::string model_id() const { return model_id_; }
+  uint64_t polling_period_ms() const { return polling_period_ms_; }
 
  private:
   std::string client_id_{"58855907228.apps.googleusercontent.com"};
@@ -43,6 +44,7 @@
   std::string default_description_{"A development device"};
   std::string default_location_{"my desk"};
   std::string model_id_{"AAA"};
+  uint64_t polling_period_ms_{7000};
 
   DISALLOW_COPY_AND_ASSIGN(BuffetConfig);
 };

buffet/device_registration_info.cc

diff --git a/buffet/device_registration_info.cc b/buffet/device_registration_info.cc
index 3f7e17c..b16e626 100644
--- a/buffet/device_registration_info.cc
+++ b/buffet/device_registration_info.cc
@@ -569,14 +569,6 @@
       FROM_HERE, base::Bind(cb, base::Owned(value.release())));
 }
 
-void PostRepeatingTask(const tracked_objects::Location& from_here,
-                       base::Closure task,
-                       base::TimeDelta delay) {
-  task.Run();
-  base::MessageLoop::current()->PostDelayedTask(
-      from_here, base::Bind(&PostRepeatingTask, from_here, task, delay), delay);
-}
-
 using ResponsePtr = scoped_ptr<chromeos::http::Response>;
 
 void SendRequestWithRetries(
@@ -840,23 +832,22 @@
 
 void DeviceRegistrationInfo::PeriodicallyPollCommands() {
   VLOG(1) << "Poll commands";
-  PostRepeatingTask(
+  command_poll_timer_.Start(
       FROM_HERE,
-      base::Bind(
-          &DeviceRegistrationInfo::FetchCommands,
-          base::Unretained(this),
-          base::Bind(&DeviceRegistrationInfo::PublishCommands,
-                     base::Unretained(this)),
-          base::Bind(&IgnoreCloudError)),
-      base::TimeDelta::FromSeconds(7));
+      base::TimeDelta::FromMilliseconds(config_->polling_period_ms()),
+      base::Bind(&DeviceRegistrationInfo::FetchCommands,
+                 base::Unretained(this),
+                 base::Bind(&DeviceRegistrationInfo::PublishCommands,
+                            base::Unretained(this)),
+                            base::Bind(&IgnoreCloudError)));
   // TODO(antonm): Use better trigger: when StateManager registers new updates,
   // it should call closure which will post a task, probably with some
   // throttling, to publish state updates.
-  PostRepeatingTask(
+  state_push_timer_.Start(
       FROM_HERE,
+      base::TimeDelta::FromMilliseconds(config_->polling_period_ms()),
       base::Bind(&DeviceRegistrationInfo::PublishStateUpdates,
-                 base::Unretained(this)),
-      base::TimeDelta::FromSeconds(7));
+                 base::Unretained(this)));
 }
 
 void DeviceRegistrationInfo::PublishCommands(const base::ListValue& commands) {

buffet/device_registration_info.h

diff --git a/buffet/device_registration_info.h b/buffet/device_registration_info.h
index 0eec540..7f5e2c6 100644
--- a/buffet/device_registration_info.h
+++ b/buffet/device_registration_info.h
@@ -15,6 +15,7 @@
 #include <base/memory/weak_ptr.h>
 #include <base/message_loop/message_loop.h>
 #include <base/time/time.h>
+#include <base/timer/timer.h>
 #include <chromeos/data_encoding.h>
 #include <chromeos/errors/error.h>
 #include <chromeos/http/http_transport.h>
@@ -240,6 +241,9 @@
   RegistrationStatus registration_status_{RegistrationStatus::kUnconfigured};
   base::Closure on_status_changed_;
 
+  base::RepeatingTimer<DeviceRegistrationInfo> command_poll_timer_;
+  base::RepeatingTimer<DeviceRegistrationInfo> state_push_timer_;
+
   friend class TestHelper;
   base::WeakPtrFactory<DeviceRegistrationInfo> weak_factory_{this};
   DISALLOW_COPY_AND_ASSIGN(DeviceRegistrationInfo);