Show Munin graph when in development for use.

app/controllers/services_controller.rb

@@ -11,7 +11,7 @@ def index
 
   def show
     @service = Service.find_by_name(params[:id])
-    @munin   = Munin.new(@service) if @service.munin_url.present?
+    @munin   = Munin.new(@service)
 
     respond_with @service
   end

app/views/hosts/show.html.erb

@@ -25,7 +25,7 @@
       class: 'btn btn-danger' %>
 </div>
 
-<% if @munin.find_service_that_hash_munin_url_by(@host) -%>
+<% if @munin.find_service_that_has_munin_url_by(@host) -%>
   <div>
     <h2><%= t('hosts.show.graphs') %></h2>
     <p><%= link_to @munin.url_for(host: @host).to_s, @munin.url_for(host: @host).to_s %></p>

app/views/services/show.html.erb

@@ -14,7 +14,7 @@
       <dd><%= @service.name %></dd>
       <dt><strong><%= model_class.human_attribute_name(:description) %>:</strong></dt>
       <dd><%= markdown(@service.description) %></dd>
-      <% if @service.munin_url.present? -%>
+      <% if @munin.activated? -%>
         <dt><strong><%= model_class.human_attribute_name(:munin_url) %>:</strong></dt>
         <dd>
           <%= link_to @service.munin_url, @service.munin_url %>

app/views/shared/_hosts.html.erb

@@ -13,7 +13,7 @@
   <table class="table table-striped">
     <thead>
       <tr>
-        <% if munin -%>
+        <% if munin.try(:activated?) -%>
           <th class="graph"><%= model_class.human_attribute_name(:graph) %></th>
         <% end -%>
         <th><%= model_class.human_attribute_name(:name) %>/<%= model_class.human_attribute_name(:ip_address) %></th>
@@ -25,7 +25,7 @@
     <tbody>
       <% hosts.each do |host| %>
         <tr>
-          <% if munin -%>
+          <% if munin.try(:activated?) -%>
             <td class="graph">
               <%= link_to image_tag(munin.graph_url_for(role: role, host: host).to_s), munin.url_for(role: role, host: host).to_s, target: '_blank'  %>
             </td>

lib/munin.rb

@@ -1,6 +1,9 @@
 require 'uri'
 
 class Munin
+  DUMMY_MUNIN_URL  = 'http://munin.example.com/'
+  DUMMY_GRAPH_PATH = '/assets/dummy-graph-for-development.png'
+
   class Error < StandardError; end
 
   attr_accessor :service
@@ -9,11 +12,23 @@ def initialize (service = nil)
     @service = service
   end
 
+  def dummy?
+    Rails.env.development? && (service && service.munin_url.blank?)
+  end
+
+  def activated?
+    dummy? || (service && service.munin_url.present?)
+  end
+
   def root
-    raise Error, 'No service defined'   unless service
-    raise Error, 'No munin_url defined' unless service.munin_url.present?
+    raise Error, 'No service defined'   if !dummy? && !service
+    raise Error, 'No munin_url defined' if !dummy? && !service.munin_url.present?
 
-    URI.parse(service.munin_url)
+    if dummy?
+      URI.parse(DUMMY_MUNIN_URL)
+    else
+      URI.parse(service.munin_url)
+    end
   end
 
   def service_url
@@ -25,24 +40,28 @@ def service_url
   def url_for (args)
     host = args[:host]
     role = args[:role] || host.roles.first
-    self.service ||= find_service_that_hash_munin_url_by(host)
+    self.service ||= find_service_that_has_munin_url_by(host)
 
     url  = root
     path = [service, role, host].map { |p| URI.escape(p.name) }.join('/')
     url += path
   end
 
   def graph_url_for (args)
-    host    = args[:host]
-    role    = args[:role]
-    url     = url_for(role: role, host: host)
-    options = { type: :load, span: :day}.merge(args[:options] || {})
+    if dummy?
+      URI.parse(DUMMY_GRAPH_PATH)
+    else
+      host    = args[:host]
+      role    = args[:role]
+      url     = url_for(role: role, host: host)
+      options = { type: :load, span: :day}.merge(args[:options] || {})
 
-    path = [url.path, URI.escape("#{options[:type].to_s}-#{options[:span].to_s}.png")].join('/')
-    url += path
+      path = [url.path, URI.escape("#{options[:type].to_s}-#{options[:span].to_s}.png")].join('/')
+      url += path
+    end
   end
 
-  def find_service_that_hash_munin_url_by (host)
+  def find_service_that_has_munin_url_by (host)
     found = nil
 
     if service && service.munin_url.present?

spec/lib/munin_spec.rb

@@ -19,9 +19,85 @@
     it { expect(munin.service).to be == service }
   end
 
+  describe '#dummy?' do
+    context 'when `Rails.env` == development', env: :development do
+      context 'and service.munin_url is set' do
+        include_context 'init_munin_with_service'
+
+        it {
+          expect(munin.dummy?).to be_false
+        }
+      end
+
+      context 'and service.munin_url is not set' do
+        include_context 'init_munin_with_service'
+        before { service.munin_url = nil }
+
+        it {
+          expect(munin.dummy?).to be_true
+        }
+      end
+    end
+  end
+
+  describe '#activated?' do
+    context 'when dummy mode for develpment', env: :development do
+      context 'and service.munin_url is set' do
+        include_context 'init_munin_with_service'
+
+        it {
+          expect(munin.activated?).to be_true
+        }
+      end
+    end
+
+    context 'when normal mode' do
+      context 'and service.munin_url is set' do
+        include_context 'init_munin_with_service'
+
+        it {
+          expect(munin.activated?).to be_true
+        }
+      end
+
+      context 'and service.munin_url is not set'do
+        include_context 'init_munin_with_service'
+        before { service.munin_url = nil }
+
+        it {
+          expect(munin.activated?).to be_false
+        }
+      end
+    end
+  end
+
   describe '#root' do
-    include_context 'init_munin_with_service'
-    it { expect(munin.root).to be == URI.parse(service.munin_url) }
+    context 'when dummy mode for development', env: :development  do
+      context 'and service is set' do
+        include_context 'init_munin_with_service'
+
+        it {
+          expect(munin.root).to be == URI.parse(service.munin_url)
+        }
+      end
+
+      context 'and service.munin_url is not set' do
+        include_context 'init_munin_with_service'
+        before { service.munin_url = nil }
+
+        it {
+          expect(munin.root).to be == URI.parse(Munin::DUMMY_MUNIN_URL)
+        }
+      end
+    end
+
+    context 'when normal mode' do
+      include_context 'init_munin_with_service'
+
+      it {
+        expect(munin.root).to be == URI.parse(service.munin_url)
+      }
+    end
   end
 
   describe '#service_url' do
@@ -50,9 +126,9 @@
   end
 
   describe '#graph_url_for' do
-    include_context 'init_munin_with_service'
-
     context 'when option is passed' do
+      include_context 'init_munin_with_service'
+
       it {
         url = munin.graph_url_for(
           role: role,
@@ -67,24 +143,36 @@
     end
 
     context 'when option is passed' do
+      include_context 'init_munin_with_service'
+
       it {
         url = munin.graph_url_for(role: role, host: host)
         expect(url).to be == URI.parse(
           "#{service.munin_url}#{URI.escape(service.name)}/#{URI.escape(role.name)}/#{URI.escape(host.name)}/load-day.png"
         )
       }
     end
+
+    context 'when `Rails.env` is development', env: :development do
+      include_context 'init_munin_with_service'
+      before { service.munin_url = nil }
+
+      it {
+        url = munin.graph_url_for(role: role, host: host)
+        expect(url).to be == URI.parse(Munin::DUMMY_GRAPH_PATH)
+      }
+    end
   end
 
-  describe '#find_service_that_hash_munin_url_by' do
+  describe '#find_service_that_has_munin_url_by' do
     context 'service is already set' do
       include_context 'init_munin_with_service'
-      it { expect(munin.find_service_that_hash_munin_url_by(host)).to be == service }
+      it { expect(munin.find_service_that_has_munin_url_by(host)).to be == service }
     end
 
     context 'service is not set' do
       include_context 'init_munin'
-      it { expect(munin.find_service_that_hash_munin_url_by(host)).to be == service }
+      it { expect(munin.find_service_that_has_munin_url_by(host)).to be == service }
     end
   end
 end

spec/spec_helper.rb

@@ -21,6 +21,14 @@
 RSpec.configure do |config|
   OmniAuth.config.test_mode = true
 
+  config.before(:each, env: :development) do
+    Rails.stub(:env).and_return(ActiveSupport::StringInquirer.new('development'))
+  end
+
+  config.after(:each, env: :development) do
+    Rails.unstub(:env)
+  end
+
   # factory girl
   FactoryGirl.find_definitions
   config.include FactoryGirl::Syntax::Methods