public static async Task ProcessCustomerAsync(
            [QueueTrigger(OperationConstants.CustomersQueueName, Connection = "StorageConnectionString")] ProcessCustomerDetail customerDetail,
            [DataRepository(DataType = typeof(AuditRecord))] DocumentRepository <AuditRecord> auditRecordRepository,
            [DataRepository(DataType = typeof(CustomerDetail))] DocumentRepository <CustomerDetail> customerRepository,
            [DataRepository(DataType = typeof(SubscriptionDetail))] DocumentRepository <SubscriptionDetail> subscriptionRepository,
            [PartnerService(
                 ApplicationId = "{PartnerCenterEndpoint.ApplicationId}",
                 Endpoint = "{PartnerCenterEndpoint.ServiceAddress}",
                 SecretName = "{PartnerCenterEndpoint.ApplicationSecretId}",
                 ApplicationTenantId = "{PartnerCenterEndpoint.TenantId}",
                 Resource = "https://graph.windows.net")] IPartner partner,
            [Queue(OperationConstants.SecurityQueueName, Connection = "StorageConnectionString")] ICollector <SecurityDetail> securityQueue,
            [Queue(OperationConstants.UtilizationQueueName, Connection = "StorageConnectionString")] ICollector <ProcessSubscriptionDetail> utilizationQueue,
            ILogger log)
        {
            IEnumerable <AuditRecord> auditRecords;
            List <SubscriptionDetail> subscriptions;
            int period;

            try
            {
                log.LogInformation($"Attempting to process information for {customerDetail.Customer.Id}.");

                //pull in customer details from PartnerCenter
                try
                {
                    Customer customer = await partner.Customers[customerDetail.Customer.Id].GetAsync().ConfigureAwait(false);
                    customerDetail.Customer.BillingProfile = customer.BillingProfile;

                    if (customerDetail.Customer.RemovedFromPartnerCenter == true)
                    {
                        customerDetail.Customer.LastProcessed = null;
                    }

                    customerDetail.Customer.RemovedFromPartnerCenter = false;
                }
                catch (ServiceClientException ex)
                {
                    customerDetail.Customer.ProcessException = ex;
                }

                if (customerDetail.Customer.RemovedFromPartnerCenter)
                {
                    // The customer no longer has relationship with the partner. So, it should not be processed.
                    return;
                }

                // Configure the value indicating the number of days of score results to retrieve starting from current date.
                period = (customerDetail.Customer.LastProcessed == null) ? 30 : (DateTimeOffset.UtcNow - customerDetail.Customer.LastProcessed).Value.Days;

                // Ensure that the period is at least 1 or greater. This ensure the request to retrieve data is succesfully.
                if (period < 1)
                {
                    period = 1;
                }

                if (period >= 30)
                {
                    period = 30;

                    try
                    {
                        customerDetail.Customer.ProcessException = null;
                        subscriptions = await GetSubscriptionsAsync(
                            partner,
                            customerDetail.Customer.Id).ConfigureAwait(false);
                    }
                    catch (ServiceClientException ex)
                    {
                        customerDetail.Customer.ProcessException = ex;
                        subscriptions = null;

                        log.LogWarning($"Encountered an exception when processing {customerDetail.Customer.Id}. Check the customer record for more information.");
                    }
                }
                else
                {
                    // Obtain a list of audit records for the specified customer that happened since the customer was last processed.
                    auditRecords = await auditRecordRepository.GetAsync(
                        r => r.CustomerId == customerDetail.Customer.Id &&
                        r.OperationDate >= customerDetail.Customer.LastProcessed,
                        customerDetail.Customer.EnvironmentId).ConfigureAwait(false);

                    subscriptions = await subscriptionRepository
                                    .GetAsync(s => s.TenantId == customerDetail.Customer.Id, customerDetail.Customer.Id)
                                    .ConfigureAwait(false);

                    // Since the period is less than 30 we can utilize the audit logs to reconstruct any subscriptions that were created.
                    subscriptions = await AuditRecordConverter.ConvertAsync(
                        partner,
                        auditRecords,
                        subscriptions,
                        customerDetail.Customer).ConfigureAwait(false);
                }

                if (subscriptions?.Count > 0)
                {
                    await subscriptionRepository.AddOrUpdateAsync(
                        subscriptions,
                        customerDetail.Customer.Id).ConfigureAwait(false);
                }

                if (customerDetail.Customer.ProcessException == null)
                {
                    securityQueue.Add(new SecurityDetail
                    {
                        AppEndpoint = customerDetail.AppEndpoint,
                        Customer    = customerDetail.Customer,
                        Period      = period.ToString(CultureInfo.InvariantCulture)
                    });

                    if (customerDetail.ProcessAzureUsage)
                    {
                        foreach (SubscriptionDetail subscription in subscriptions.Where(s => s.BillingType == BillingType.Usage))
                        {
                            utilizationQueue.Add(new ProcessSubscriptionDetail
                            {
                                PartnerCenterEndpoint = customerDetail.PartnerCenterEndpoint,
                                Subscription          = subscription
                            });
                        }
                    }

                    customerDetail.Customer.LastProcessed = DateTimeOffset.UtcNow;
                }

                await customerRepository.AddOrUpdateAsync(customerDetail.Customer).ConfigureAwait(false);

                log.LogInformation($"Successfully processed customer {customerDetail.Customer.Id}. Exception(s): {(customerDetail.Customer.ProcessException != null ? "yes" : "no")}");
            }
            finally
            {
                auditRecords  = null;
                subscriptions = null;
            }
        }
        public static async Task ProcessPartnerAsync(
            [QueueTrigger(OperationConstants.PartnersQueueName, Connection = "StorageConnectionString")] EnvironmentDetail environment,
            [DataRepository(DataType = typeof(AuditRecord))] DocumentRepository <AuditRecord> auditRecordRepository,
            [DataRepository(DataType = typeof(CustomerDetail))] DocumentRepository <CustomerDetail> customerRepository,
            [DataRepository(
                 DataType = typeof(EnvironmentDetail))] DocumentRepository <EnvironmentDetail> environmentRepository,
            [PartnerService(
                 ApplicationId = "{PartnerCenterEndpoint.ApplicationId}",
                 Endpoint = "{PartnerCenterEndpoint.ServiceAddress}",
                 SecretName = "{PartnerCenterEndpoint.ApplicationSecretId}",
                 ApplicationTenantId = "{PartnerCenterEndpoint.TenantId}",
                 Resource = "https://graph.windows.net")] IPartner client,
            [Queue(OperationConstants.CustomersQueueName, Connection = "StorageConnectionString")] ICollector <ProcessCustomerDetail> customerQueue,
            ILogger log)
        {
            List <AuditRecord>    auditRecords;
            List <CustomerDetail> customers;
            int days;

            try
            {
                log.LogInformation($"Starting to process the {environment.FriendlyName} CSP environment.");

                // Calculate the number of days that have gone by, since the last successful synchronization.
                days = (environment.LastProcessed == null) ? 30 : (DateTimeOffset.UtcNow - environment.LastProcessed).Days;

                if (days >= 90)
                {
                    // Only audit records for the past 90 days are available from Partner Center.
                    days = 89;
                }
                else if (days <= 0)
                {
                    // Ensure that in all circumstances at least one day of records will be returned.
                    days = 1;
                }

                if (days >= 30)
                {
                    customers = await GetCustomersAsync(client, environment).ConfigureAwait(false);
                }
                else
                {
                    auditRecords = await GetAuditRecordsAsyc(
                        client,
                        DateTime.UtcNow.AddDays(-days),
                        DateTime.UtcNow).ConfigureAwait(false);

                    if (auditRecords.Count > 0)
                    {
                        log.LogInformation($"Importing {auditRecords.Count} audit records available between now and the previous day for the {environment.FriendlyName} Region.");

                        // Add, or update, each audit record to the database.
                        await auditRecordRepository.AddOrUpdateAsync(
                            auditRecords,
                            environment.Id).ConfigureAwait(false);
                    }

                    customers = await customerRepository.GetAsync(c => c.EnvironmentId == environment.Id).ConfigureAwait(false);

                    log.LogInformation($"Retrieved {customers.Count()} customers from the repository for the {environment.FriendlyName} Region");

                    customers = await AuditRecordConverter.ConvertAsync(
                        client,
                        auditRecords,
                        customers,
                        new Dictionary <string, string> {
                        { "EnvironmentId", environment.Id }
                    },
                        log).ConfigureAwait(false);
                }

                log.LogInformation($"Saving {customers.Count()} customers to the repository for the {environment.FriendlyName} Region");
                // Add, or update, each customer to the database.
                await customerRepository.AddOrUpdateAsync(customers).ConfigureAwait(false);

                log.LogInformation($"Adding {customers.Count()} customers to the queue for processing for the {environment.FriendlyName} Region");
                foreach (CustomerDetail customer in customers)
                {
                    // Write the customer to the customers queue to start processing the customer.
                    customerQueue.Add(new ProcessCustomerDetail
                    {
                        AppEndpoint           = environment.AppEndpoint,
                        Customer              = customer,
                        PartnerCenterEndpoint = environment.PartnerCenterEndpoint,
                        ProcessAzureUsage     = environment.ProcessAzureUsage
                    });
                }

                environment.LastProcessed = DateTimeOffset.UtcNow;
                await environmentRepository.AddOrUpdateAsync(environment).ConfigureAwait(false);

                log.LogInformation($"Successfully processed the {environment.FriendlyName} CSP environment.");
            }
            finally
            {
                auditRecords = null;
                customers    = null;
            }
        }