[enh] settings.yml: implement general.enable_metrics

* allow not to record metrics (response time, etc...)
* this commit doesn't change the UI. If the metrics are disabled
  /stats and /stats/errors will return empty response.
  in /preferences, the columns response time and reliability will be empty.

1 files changed, 8 insertions, 4 deletions

diff --git a/searx/metrics/__init__.py b/searx/metrics/__init__.py
index 37f0ba121..bc755b96b 100644
--- a/searx/metrics/__init__.py
+++ b/searx/metrics/__init__.py
@@ -9,7 +9,7 @@ from timeit import default_timer
 from operator import itemgetter
 
 from searx.engines import engines
-from .models import HistogramStorage, CounterStorage
+from .models import HistogramStorage, CounterStorage, VoidHistogram, VoidCounterStorage
 from .error_recorder import count_error, count_exception, errors_per_engines
 
 __all__ = [
@@ -69,14 +69,18 @@ def counter(*args):
     return counter_storage.get(*args)
 
 
-def initialize(engine_names=None):
+def initialize(engine_names=None, enabled=True):
     """
     Initialize metrics
     """
     global counter_storage, histogram_storage  # pylint: disable=global-statement
 
-    counter_storage = CounterStorage()
-    histogram_storage = HistogramStorage()
+    if enabled:
+        counter_storage = CounterStorage()
+        histogram_storage = HistogramStorage()
+    else:
+        counter_storage = VoidCounterStorage()
+        histogram_storage = HistogramStorage(histogram_class=VoidHistogram)
 
     # max_timeout = max of all the engine.timeout
     max_timeout = 2