adding skip on no subs

lib/noticent/config.rb

@@ -2,11 +2,11 @@
 
 module Noticent
   def self.configure(options = {}, &block)
-    if ENV['NOTICENT_RSPEC'] == '1'
+    if ENV["NOTICENT_RSPEC"] == "1"
       options = options.merge(
-        base_module_name: 'Noticent::Testing',
+        base_module_name: "Noticent::Testing",
         base_dir: File.expand_path("#{File.dirname(__FILE__)}/../../testing"),
-        halt_on_error: true
+        halt_on_error: true,
       )
     end
 
@@ -116,6 +116,10 @@ def halt_on_error
       @options[:halt_on_error].nil? ? false : @options[:halt_on_error]
     end
 
+    def skip_alert_with_no_subscribers
+      @options[:skip_alert_with_no_subscribers].nil? ? false : @options[:skip_alert_with_no_subscribers]
+    end
+
     def default_value
       @options[:default_value].nil? ? false : @options[:default_value]
     end
@@ -125,19 +129,19 @@ def use_sub_modules
     end
 
     def payload_dir
-      File.join(base_dir, 'payloads')
+      File.join(base_dir, "payloads")
     end
 
     def scope_dir
-      File.join(base_dir, 'scopes')
+      File.join(base_dir, "scopes")
     end
 
     def channel_dir
-      File.join(base_dir, 'channels')
+      File.join(base_dir, "channels")
     end
 
     def view_dir
-      File.join(base_dir, 'views')
+      File.join(base_dir, "views")
     end
 
     def create_dynamics
@@ -161,7 +165,7 @@ class Builder
       def initialize(options = {}, &block)
         @options = options
         @config = Noticent::Config.new(options)
-        raise BadConfiguration, 'no OptInProvider configured' if @config.opt_in_provider.nil?
+        raise BadConfiguration, "no OptInProvider configured" if @config.opt_in_provider.nil?
 
         instance_eval(&block) if block_given?
 
@@ -192,6 +196,10 @@ def halt_on_error=(value)
         @options[:halt_on_error] = value
       end
 
+      def skip_alert_with_no_subscribers=(value)
+        @options[:skip_alert_with_no_subscribers] = value
+      end
+
       def use_sub_modules=(value)
         @options[:use_sub_modules] = value
       end

lib/noticent/dispatcher.rb

@@ -34,8 +34,8 @@ def recipients(notifier_name)
 
     # only returns recipients that have opted-in for this channel
     def filter_recipients(recipients, channel)
-      raise ArgumentError, 'channel should be a string or symbol' unless channel.is_a?(String) || channel.is_a?(Symbol)
-      raise ArgumentError, 'recipients is nil' if recipients.nil?
+      raise ArgumentError, "channel should be a string or symbol" unless channel.is_a?(String) || channel.is_a?(Symbol)
+      raise ArgumentError, "recipients is nil" if recipients.nil?
 
       recipients.select { |recipient| @config.opt_in_provider.opted_in?(recipient_id: recipient.id, scope: scope.name, entity_id: @entity_id, alert_name: alert.name, channel_name: channel) }
     end
@@ -45,6 +45,12 @@ def dispatch
         recs = recipients(notifier.recipient)
         notifier.applicable_channels.each do |channel|
           to_send = filter_recipients(recs, channel.name)
+
+          if to_send.count == 0 && @config.skip_alert_with_no_subscribers
+            Noticent.configuration.logger.info "Skipping alert #{alert.name} as they are no subscribers"
+            return
+          end
+
           channel_instance = channel.instance(@config, to_send, @payload, @configuration)
           begin
             raise Noticent::BadConfiguration, "channel #{channel.name} (#{channel.klass}) doesn't have a method called #{alert.name}" unless channel_instance.respond_to? alert.name
@@ -54,7 +60,7 @@ def dispatch
             # log and move on
             raise if @config.halt_on_error
 
-            Noticent.logger.error e
+            Noticent.configuration.logger.error e
           end
         end
       end
@@ -63,12 +69,12 @@ def dispatch
     private
 
     def validate!
-      raise Noticent::BadConfiguration, 'no base_dir defined' if @config.base_dir.nil?
+      raise Noticent::BadConfiguration, "no base_dir defined" if @config.base_dir.nil?
       raise Noticent::MissingConfiguration if @config.nil?
       raise Noticent::BadConfiguration if @config.alerts.nil?
       raise Noticent::InvalidAlert, "no alert #{@alert_name} found" if @config.alerts[@alert_name].nil?
-      raise ::ArgumentError, 'payload is nil' if @payload.nil?
-      raise ::ArgumentError, 'alert is not a symbol' unless @alert_name.is_a?(Symbol)
+      raise ::ArgumentError, "payload is nil" if @payload.nil?
+      raise ::ArgumentError, "alert is not a symbol" unless @alert_name.is_a?(Symbol)
       raise Noticent::BadConfiguration, "payload (#{@payload.class}) doesn't belong to this scope (#{scope.name}) as it requires #{scope.payload_class}" unless !scope.payload_class.nil? && @payload.is_a?(scope.payload_class)
       raise Noticent::BadConfiguration, "payload doesn't have a #{scope.name}_id method" unless @payload.respond_to?("#{scope.name}_id")
     end

spec/dispatcher_spec.rb

@@ -1,9 +1,9 @@
 # frozen_string_literal: true
 
-require 'spec_helper'
+require "spec_helper"
 
 describe Noticent::Dispatcher do
-  it 'should find scope by alert' do
+  it "should find scope by alert" do
     p1 = build(:post_payload)
     Noticent.configure do
       scope :post do
@@ -23,7 +23,7 @@
     expect(dispatcher.scope.name).to eq(:post)
   end
 
-  it 'should find all recipients' do
+  it "should find all recipients" do
     p1 = build(:post_payload)
     Noticent.configure do
       scope :post do
@@ -45,7 +45,7 @@
     expect(dispatcher.notifiers[:slack]).to be_nil
   end
 
-  it 'should call scope to fetch recipients' do
+  it "should call scope to fetch recipients" do
     p1 = build(:post_payload)
     Noticent.configure do
       scope :post do
@@ -67,7 +67,7 @@
     expect(dispatcher.notifiers[:slack]).to be_nil
   end
 
-  it 'should fetch all recipients' do
+  it "should fetch all recipients" do
     p1 = build(:post_payload, _users: create_list(:recipient, 4))
     Noticent.configure do
       scope :post do
@@ -87,13 +87,13 @@
     expect(dispatcher.recipients(:users).count).to eq(4)
   end
 
-  it 'should filter recipients' do
+  it "should filter recipients" do
     rec = create_list(:recipient, 2)
     p1 = build(:post_payload, _users: rec)
     r1 = rec[0]
 
     Noticent.configure do
-      channel(:email) {}
+      channel(:email) { }
       scope :post do
         alert :foo do
           notify(:users).on(:default)
@@ -120,11 +120,11 @@
     expect(dispatcher.filter_recipients(rec, :email)[0]).to equal(r1)
   end
 
-  it 'should dispatch' do
+  it "should dispatch" do
     class Email < ::Noticent::Channel
       def new_signup
-        raise Noticent::Error, 'bad recipients' unless recipients.count == 1
-        raise Noticent::Error, 'bad payload' unless payload.is_a? Noticent::Testing::PostPayload
+        raise Noticent::Error, "bad recipients" unless recipients.count == 1
+        raise Noticent::Error, "bad payload" unless payload.is_a? Noticent::Testing::PostPayload
       end
     end
 
@@ -133,7 +133,7 @@ def new_signup
     r1 = rec[0]
 
     Noticent.configure do
-      channel(:email, klass: Email) {}
+      channel(:email, klass: Email) { }
       scope :post do
         alert :new_signup do
           notify(:users).on(:default)
@@ -153,7 +153,53 @@ def new_signup
     dispatcher.dispatch
   end
 
-  it 'should reject bad payloads' do
+  it "should skip dispatch with no subs" do
+    class Email < ::Noticent::Channel
+      def new_signup
+        raise Noticent::Error, "no recipents" if recipients.count == 0
+      end
+    end
+
+    rec = create_list(:recipient, 4)
+    payload = build(:post_payload, _users: rec)
+    r1 = rec[0]
+
+    Noticent.configure do
+      channel(:email, klass: Email) { }
+      scope :post do
+        alert :new_signup do
+          notify(:users).on(:default)
+        end
+      end
+    end
+
+    dispatcher = Noticent::Dispatcher.new(
+      Noticent.configuration,
+      :new_signup,
+      payload
+    )
+    expect { dispatcher.dispatch }.to raise_error Noticent::Error
+
+    Noticent.configure do |config|
+      config.skip_alert_with_no_subscribers = true
+      channel(:email, klass: Email) { }
+      scope :post do
+        alert :new_signup do
+          notify(:users).on(:default)
+        end
+      end
+    end
+
+    dispatcher = Noticent::Dispatcher.new(
+      Noticent.configuration,
+      :new_signup,
+      payload
+    )
+
+    expect { dispatcher.dispatch }.not_to raise_error
+  end
+
+  it "should reject bad payloads" do
     Noticent.configure do
       scope :post, payload_class: ::Noticent::Testing::PostPayload do
         alert(:foo) { notify :users }
@@ -167,9 +213,9 @@ class FakePostPayload
     payload = FakePostPayload.new
     expect do
       Noticent::Dispatcher.new(
-          Noticent.configuration,
-          :foo,
-          payload
+        Noticent.configuration,
+        :foo,
+        payload
       )
     end.to raise_error Noticent::BadConfiguration
   end