From 3252e8cc7ed3128cea5db4f76f18d4aa1f513147 Mon Sep 17 00:00:00 2001
From: Rick Carlino <rick.carlino@gmail.com>
Date: Mon, 15 Jul 2019 17:08:51 -0500
Subject: [PATCH] Don't send MQTT throttle emails more than once per day.

---
 app/models/device.rb                                  | 11 ++++++++---
 ...14412_add_mqtt_throttle_email_sent_at_to_device.rb |  7 +++++++
 db/structure.sql                                      |  6 ++++--
 spec/models/device_spec.rb                            |  7 +++++++
 4 files changed, 26 insertions(+), 5 deletions(-)
 create mode 100644 db/migrate/20190715214412_add_mqtt_throttle_email_sent_at_to_device.rb

diff --git a/app/models/device.rb b/app/models/device.rb
index bb56349f6..7b921a5dc 100644
--- a/app/models/device.rb
+++ b/app/models/device.rb
@@ -201,8 +201,13 @@ class Device < ApplicationRecord
       "see https://developer.farm.bot/docs/connectivity-issues"
   def self.connection_warning(username)
     device_id = username.split("_").last.to_i || 0
-    self
-      .find(device_id)
-      .tell(TOO_MANY_CONNECTIONS, ["fatal_email"]) if self.exists?(device_id)
+    device = self.find_by(id: device_id)
+    return unless device
+
+    last_sent_at = device.mqtt_rate_limit_email_sent_at || 4.years.ago
+    if last_sent_at < 1.day.ago
+      device.update_attributes!(mqtt_rate_limit_email_sent_at: Time.now)
+      device.tell(TOO_MANY_CONNECTIONS, ["fatal_email"])
+    end
   end
 end
diff --git a/db/migrate/20190715214412_add_mqtt_throttle_email_sent_at_to_device.rb b/db/migrate/20190715214412_add_mqtt_throttle_email_sent_at_to_device.rb
new file mode 100644
index 000000000..4f32bfe76
--- /dev/null
+++ b/db/migrate/20190715214412_add_mqtt_throttle_email_sent_at_to_device.rb
@@ -0,0 +1,7 @@
+class AddMqttThrottleEmailSentAtToDevice < ActiveRecord::Migration[5.2]
+  def change
+    add_column :devices,
+               :mqtt_rate_limit_email_sent_at,
+               :datetime
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index a7cf78f2d..d3bc718d5 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -206,7 +206,8 @@ CREATE TABLE public.devices (
     mounted_tool_id bigint,
     created_at timestamp without time zone,
     updated_at timestamp without time zone,
-    serial_number character varying(32)
+    serial_number character varying(32),
+    mqtt_rate_limit_email_sent_at timestamp without time zone
 );
 
 
@@ -3019,6 +3020,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20190621160042'),
 ('20190621202204'),
 ('20190701155706'),
-('20190709194037');
+('20190709194037'),
+('20190715214412');
 
 
diff --git a/spec/models/device_spec.rb b/spec/models/device_spec.rb
index 06cef0b8c..aa0db2172 100644
--- a/spec/models/device_spec.rb
+++ b/spec/models/device_spec.rb
@@ -102,4 +102,11 @@ describe Device do
     expect(results).to_not include(🚑)
     expect(results).to_not include(🍞)
   end
+
+  it "throttled emails about MQTT rate limiting" do
+    device.update_attributes!(mqtt_rate_limit_email_sent_at: 2.days.ago)
+    Device.connection_warning("device_#{device.id.to_s}")
+    time = device.reload.mqtt_rate_limit_email_sent_at
+    expect(time).to be > 1.minute.ago
+  end
 end