Logging successful task executions in utask _MetricRecorder (#4492)

### Motivation

Progression task was failing 100% of the time due to an unhandled
exception. This PR adds further logging so we can confirm if this is the
case.

This also makes UNTRIAGED_TESTCASE_AGE and
TESTCASE_UPLOAD_TRIAGE_DURATION in hours, instead of seconds, for better
readability

Author: vitorguidi

src/clusterfuzz/_internal/bot/tasks/utasks/__init__.py

@@ -166,6 +166,11 @@ def __exit__(self, _exc_type, _exc_value, _traceback):
     monitoring_metrics.TASK_OUTCOME_COUNT_BY_ERROR_TYPE.increment(
         trimmed_labels)
 
+    if error_condition != 'UNHANDLED_EXCEPTION':
+      task = self._labels['task']
+      subtask = self._labels['subtask']
+      logs.info(f'Task {task}, at subtask {subtask}, finished successfully.')
+
 
 def ensure_uworker_env_type_safety(uworker_env):
   """Converts all values in |uworker_env| to str types.

src/clusterfuzz/_internal/common/testcase_utils.py

@@ -47,7 +47,7 @@ def emit_testcase_triage_duration_metric(testcase_id: int, step: str):
   ]
   elapsed_time_since_upload = datetime.datetime.utcnow()
   elapsed_time_since_upload -= testcase_upload_metadata.timestamp
-  elapsed_time_since_upload = elapsed_time_since_upload.total_seconds()
+  elapsed_time_since_upload = elapsed_time_since_upload.total_seconds() / 3600
 
   testcase = data_handler.get_testcase_by_id(testcase_id)
 

src/clusterfuzz/_internal/cron/triage.py

@@ -320,7 +320,7 @@ def _emit_untriaged_testcase_age_metric(critical_tasks_completed: bool,
   logs.info(f'Emiting UNTRIAGED_TESTCASE_AGE for testcase {testcase.key.id()} '
             f'(age = {testcase.get_age_in_seconds()})')
   monitoring_metrics.UNTRIAGED_TESTCASE_AGE.add(
-      testcase.get_age_in_seconds(),
+      testcase.get_age_in_seconds() / 3600,
       labels={
           'job': testcase.job_type,
           'platform': testcase.platform,

src/clusterfuzz/_internal/metrics/monitoring_metrics.py

@@ -234,7 +234,8 @@
 TESTCASE_UPLOAD_TRIAGE_DURATION = monitor.CumulativeDistributionMetric(
     'uploaded_testcase_analysis/triage_duration_secs',
     description=('Time elapsed between testcase upload and completion'
-                 ' of relevant tasks in the testcase upload lifecycle.'),
+                 ' of relevant tasks in the testcase upload lifecycle, '
+                 'in hours.'),
     bucketer=monitor.GeometricBucketer(),
     field_spec=[
         monitor.StringField('step'),
@@ -357,7 +358,7 @@
     'issues/untriaged_testcase_age',
     description='Age of testcases that were not yet triaged '
     '(have not yet completed analyze, regression,'
-    ' minimization, impact task), in seconds.',
+    ' minimization, impact task), in hours.',
     bucketer=monitor.GeometricBucketer(),
     field_spec=[
         monitor.StringField('job'),