execution_stage: fix wrong exception thrown for non-unique stages

The metrics API now also enforces uniqueness, and as it is called before execution stage registration, it throws earlier, and confuses the unit test because a different exception type is expected. Fix by reversing the order of metrics registration and execution stage registration.
ysbarney · May 3, 2017 · 4a3118c · 4a3118c
1 parent e7fbd02
commit 4a3118c
Showing 1 changed file with 30 additions and 26 deletions.
diff --git a/core/execution_stage.hh b/core/execution_stage.hh
@@ -28,6 +28,7 @@
 #include "metrics.hh"
 #include "util/reference_wrapper.hh"
 #include "util/gcc6-concepts.hh"
+#include "../util/defer.hh"
 
 namespace seastar {
 
@@ -407,34 +408,37 @@ auto make_execution_stage(const sstring& name, Ret (Object::*fn)(Args...) const)
 
 inline execution_stage::execution_stage(const sstring& name)
     : _name(name)
-    , _metric_group("execution_stages", {
-        metrics::make_derive("tasks_scheduled",
-                             metrics::description("Counts tasks scheduled by execution stages"),
-                             { metrics::label_instance("execution_stage", name), },
-                             [name, &esm = internal::execution_stage_manager::get()] {
-                                 return esm.get_stage(name)->get_stats().tasks_scheduled;
-                             }),
-        metrics::make_derive("tasks_preempted",
-                             metrics::description("Counts tasks which were preempted before execution all queued operations"),
-                             { metrics::label_instance("execution_stage", name), },
-                             [name, &esm = internal::execution_stage_manager::get()] {
-                                 return esm.get_stage(name)->get_stats().tasks_preempted;
-                             }),
-        metrics::make_derive("function_calls_enqueued",
-                             metrics::description("Counts function calls added to execution stages queues"),
-                             { metrics::label_instance("execution_stage", name), },
-                             [name, &esm = internal::execution_stage_manager::get()] {
-                                 return esm.get_stage(name)->get_stats().function_calls_enqueued;
-                             }),
-        metrics::make_derive("function_calls_executed",
-                             metrics::description("Counts function calls executed by execution stages"),
-                             { metrics::label_instance("execution_stage", name), },
-                             [name, &esm = internal::execution_stage_manager::get()] {
-                                 return esm.get_stage(name)->get_stats().function_calls_executed;
-                             }),
-      })
+
 {
     internal::execution_stage_manager::get().register_execution_stage(*this);
+    auto undo = defer([&] { internal::execution_stage_manager::get().unregister_execution_stage(*this); });
+    _metric_group = metrics::metric_group("execution_stages", {
+             metrics::make_derive("tasks_scheduled",
+                                  metrics::description("Counts tasks scheduled by execution stages"),
+                                  { metrics::label_instance("execution_stage", name), },
+                                  [name, &esm = internal::execution_stage_manager::get()] {
+                                      return esm.get_stage(name)->get_stats().tasks_scheduled;
+                                  }),
+             metrics::make_derive("tasks_preempted",
+                                  metrics::description("Counts tasks which were preempted before execution all queued operations"),
+                                  { metrics::label_instance("execution_stage", name), },
+                                  [name, &esm = internal::execution_stage_manager::get()] {
+                                      return esm.get_stage(name)->get_stats().tasks_preempted;
+                                  }),
+             metrics::make_derive("function_calls_enqueued",
+                                  metrics::description("Counts function calls added to execution stages queues"),
+                                  { metrics::label_instance("execution_stage", name), },
+                                  [name, &esm = internal::execution_stage_manager::get()] {
+                                      return esm.get_stage(name)->get_stats().function_calls_enqueued;
+                                  }),
+             metrics::make_derive("function_calls_executed",
+                                  metrics::description("Counts function calls executed by execution stages"),
+                                  { metrics::label_instance("execution_stage", name), },
+                                  [name, &esm = internal::execution_stage_manager::get()] {
+                                      return esm.get_stage(name)->get_stats().function_calls_executed;
+                                  }),
+           });
+    undo.cancel();
 }
 
 inline execution_stage::~execution_stage()