Add idempotent Que job for e-invoice sending

app/jobs/send_e_invoice_job.rb

@@ -0,0 +1,39 @@
+class SendEInvoiceJob < Que::Job
+
+  def run(invoice)
+    return if invoice.e_invoice_sent_at
+
+    e_invoice = invoice.to_e_invoice
+    e_invoice.deliver
+
+    ActiveRecord::Base.transaction do
+      invoice.update(e_invoice_sent_at: Time.zone.now)
+      log_success(invoice)
+      destroy
+    end
+
+  rescue Savon::Error => e
+    log_error(invoice: invoice, error: e)
+  end
+
+  private
+
+  def log_success(invoice)
+    message = "E-Invoice for an invoice with ID # #{invoice.id} was sent successfully"
+    logger.info message
+  end
+
+  def log_error(invoice:, error:)
+    message = <<~TEXT.squish
+      There was an error sending e-invoice for invoice with ID # #{invoice.id}.
+      The error message was the following: #{error}.
+      This job will retry
+    TEXT
+    logger.error message
+  end
+
+  def logger
+    Rails.logger
+  end
+
+end

db/migrate/20200204103125_add_e_invoice_sent_at_to_invoice.rb

@@ -0,0 +1,5 @@
+class AddEInvoiceSentAtToInvoice < ActiveRecord::Migration[5.0]
+  def change
+    add_column :invoices, :e_invoice_sent_at, :datetime
+  end
+end

db/structure.sql

@@ -886,6 +886,7 @@ CREATE TABLE public.invoices (
     in_directo boolean DEFAULT false,
     buyer_vat_no character varying,
     issue_date date NOT NULL,
+    e_invoice_sent_at timestamp without time zone,
     CONSTRAINT invoices_due_date_is_not_before_issue_date CHECK ((due_date >= issue_date))
 );
 
@@ -4339,6 +4340,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20191212133136'),
 ('20191227110904'),
 ('20200113091254'),
-('20200115102202');
+('20200115102202'),
+('20200204103125');