public virtual void RefreshCounters()

in Amazon.KinesisTap.Windows/PerformanceCounterSource.cs [236:297]
50 lines of code
13 McCabe index (conditional complexity)

        public virtual void RefreshCounters()
        {
            var newCounters = new HashSet<MetricKey>();
            foreach (var categoryInfo in _categoryInfos)
            {
                try
                {
                    // add the counters available in the category to the set
                    AddCategoryCountersToSet(categoryInfo, newCounters);
                }
                catch (Exception ex)
                {
                    _context.Logger?.LogWarning(0, ex, $"Could not add counters for category {categoryInfo.CategoryName}.");
                }
            }

            // now we run a 'diff' between the new and the current set of counters
            // first we check to see what counters are stale
            var stale = new List<MetricKey>();
            foreach (var counterKey in _metricCounters.Keys)
            {
                if (!newCounters.Contains(counterKey))
                {
                    stale.Add(counterKey);
                }
            }

            // remove the stale counters
            foreach (var staleCounter in stale)
            {
                _metricCounters[staleCounter].Dispose();
                _metricCounters.Remove(staleCounter);
                _context.Logger?.LogInformation($"Removed performance counter: category {staleCounter.Category} instance {staleCounter.Id} counter {staleCounter.Name}.");
            }

            // add in the new counters
            foreach (var newCounterKey in newCounters)
            {
                if (_metricCounters.ContainsKey(newCounterKey))
                {
                    continue;
                }

                try
                {
                    var counter = new PerformanceCounter(newCounterKey.Category, newCounterKey.Name, newCounterKey.Id);
                    _metricCounters[newCounterKey] = counter;
                    var instancePhrase = string.IsNullOrEmpty(counter.InstanceName)
                        ? string.Empty
                        : $" instance {counter.InstanceName}";
                    _context.Logger?.LogInformation($"Added performance counter: category {counter.CategoryName}{instancePhrase} counter {counter.CounterName}.");
                }
                catch (Exception ex) when (ex is InvalidOperationException || ex is ArgumentNullException || ex is UnauthorizedAccessException || ex is Win32Exception)
                {
                    // catch the exception caused by the performance counter constructor
                    // this should not happen, because the counter key is obtained from the system's API
                    // however we want to make sure that failure in creating one counter does not impact others.
                    _context.Logger?.LogError(0, ex,
                        $"Error adding counter: category {newCounterKey.Category} instance {newCounterKey.Id} counter {newCounterKey.Name}.");
                }
            }
        }