public void Initialize()

in src/Microsoft.Azure.WebJobs.Logging.ApplicationInsights/Initializers/WebJobsTelemetryInitializer.cs [42:139]
78 lines of code
22 McCabe index (conditional complexity)

        public void Initialize(ITelemetry telemetry)
        {
            if (telemetry == null)
            {
                return;
            }

            var telemetryContext = telemetry.Context;
            telemetryContext.Cloud.RoleInstance = _roleInstanceName;
            if (telemetryContext.Location.Ip == null)
            {
                telemetryContext.Location.Ip = LoggingConstants.ZeroIpAddress;
            }

            // Do not apply state properties if optimization is enabled.
            if (_options.EnableMetricsCustomDimensionOptimization && telemetry is MetricTelemetry)
            {
                // Remove the Host instance ID property, since it's not needed.
                telemetryContext.Properties.Remove(LoggingConstants.HostInstanceIdKey);
                return;
            }
            else
            {
                telemetryContext.Properties[LogConstants.ProcessIdKey] = _currentProcessId;

                // Apply our special scope properties
                IReadOnlyDictionary<string, object> scopeProps = DictionaryLoggerScope.GetMergedStateDictionaryOrNull();

                // this could be telemetry tracked in scope of function call - then we should apply the logger scope
                // or RequestTelemetry tracked by the WebJobs SDK or AppInsight SDK - then we should apply Activity.Tags
                if (scopeProps?.Count > 0)
                {
                    if (!telemetryContext.Properties.ContainsKey(LogConstants.InvocationIdKey))
                    {
                        if (scopeProps?.GetValueOrDefault<string>(ScopeKeys.FunctionInvocationId) is string invocationId)
                        {
                            telemetryContext.Properties[LogConstants.InvocationIdKey] = invocationId;
                        }
                    }
                    
                    telemetryContext.Operation.Name = scopeProps.GetValueOrDefault<string>(ScopeKeys.FunctionName);

                    // Apply Category, LogLevel event details to all telemetry
                    if (!telemetryContext.Properties.ContainsKey(LogConstants.CategoryNameKey))
                    {
                        if (scopeProps.GetValueOrDefault<string>(LogConstants.CategoryNameKey) is string category)
                        {
                            telemetryContext.Properties[LogConstants.CategoryNameKey] = category;
                        }
                    }

                    if (!telemetryContext.Properties.ContainsKey(LogConstants.LogLevelKey))
                    {
                        if (scopeProps.GetValueOrDefault<LogLevel?>(LogConstants.LogLevelKey) is LogLevel logLevel)
                        {
                            telemetryContext.Properties[LogConstants.LogLevelKey] = logLevel.ToStringOptimized();
                        }
                    }

                    if (!telemetryContext.Properties.ContainsKey(LogConstants.EventIdKey))
                    {
                        if (scopeProps.GetValueOrDefault<int>(LogConstants.EventIdKey) is int eventId && eventId != 0)
                        {
                            telemetryContext.Properties[LogConstants.EventIdKey] = eventId.ToString(CultureInfo.InvariantCulture);
                        }
                    }

                    if (!telemetryContext.Properties.ContainsKey(LogConstants.EventNameKey))
                    {
                        if (scopeProps.GetValueOrDefault<string>(LogConstants.EventNameKey) is string eventName)
                        {
                            telemetryContext.Properties[LogConstants.EventNameKey] = eventName;
                        }
                    }
                }

                // we may track traces/dependencies after function scope ends - we don't want to update those
                if (telemetry is RequestTelemetry request)
                {
                    UpdateRequestProperties(request);

                    Activity currentActivity = Activity.Current;
                    if (currentActivity != null)
                    {
                        foreach (var tag in currentActivity.Tags)
                        {
                            // Apply well-known tags and custom properties, 
                            // but ignore internal ai tags
                            if (!TryApplyProperty(request, tag) &&
                                !tag.Key.StartsWith("ai_"))
                            {
                                request.Properties[tag.Key] = tag.Value;
                            }
                        }
                    }
                }
            }
        }