private async Task ConfigChangePoller()

in Amazon.KinesisTap.Hosting/SessionManager.cs [164:233]
57 lines of code
13 McCabe index (conditional complexity)

        private async Task ConfigChangePoller(CancellationToken stopToken)
        {
            var extraConfigs = new HashSet<string>();

            while (!stopToken.IsCancellationRequested)
            {
                try
                {
                    var shouldPoll = Interlocked.Exchange(ref _configChanged, 0) > 0;
                    if (shouldPoll)
                    {
                        // poll the default session first
                        await PollConfig(_defaultConfigFilePath, true, stopToken);

                        // get the set of extra config files
                        extraConfigs.Clear();
                        if (!Directory.Exists(_extraConfigDirPath))
                        {
                            continue;
                        }

                        var searchExtraConfigs = Directory.EnumerateFiles(_extraConfigDirPath, "*.json", SearchOption.TopDirectoryOnly);
                        foreach (var f in searchExtraConfigs)
                        {
                            if (ShouldIgnoreConfigFile(f))
                            {
                                continue;
                            }
                            extraConfigs.Add(f);
                        }

                        // List the sessions that are currently running but are no longer present in the list of configuration files.
                        // Exclude configurations that have been loaded from another location, since these are managed by an external component.
                        var sessionsToStop = ConfigPathToSessionMap
                            .Where(kv => kv.Key != _defaultConfigFilePath
                                && !extraConfigs.Contains(kv.Key)
                                && kv.Key.StartsWith(_extraConfigDirPath))
                            .Select(kv => kv.Key)
                            .ToList(); // Force the enumerable into a List.

                        foreach (var configPath in sessionsToStop)
                        {
                            stopToken.ThrowIfCancellationRequested();
                            if (ConfigPathToSessionMap.TryRemove(configPath, out var removedSession))
                            {
                                // always stop the session AFTER it's been removed from the mapping
                                await TerminateSession(removedSession, default);
                            }
                        }

                        // poll and start sessions as neccessary
                        foreach (var configFile in extraConfigs)
                        {
                            stopToken.ThrowIfCancellationRequested();
                            await PollConfig(configFile, false, stopToken);
                        }
                    }

                    await Task.Delay(ConfigChangePollingIntervalMs, stopToken);
                }
                catch (OperationCanceledException)
                {
                    break;
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error watching config file changes.");
                }
            }
        }