Merge 70850900-insight-always-available to master

[Completes #70850900]

Author: nebhale

lib/java_buildpack/framework/spring_insight.rb

@@ -15,7 +15,9 @@
 # limitations under the License.
 
 require 'java_buildpack/component/base_component'
+require 'java_buildpack/util/cache/internet_availability'
 require 'java_buildpack/framework'
+require 'java_buildpack/util/dash_case'
 require 'tmpdir'
 require 'fileutils'
 require 'uri'
@@ -41,7 +43,9 @@ def detect
 
       # (see JavaBuildpack::Component::BaseComponent#compile)
       def compile
-        download(@version, @uri.chomp('/') + AGENT_DOWNLOAD_URI_SUFFIX) { |file| expand file } # TODO: AGENT_DOWNLOAD_URI_SUFFIX To be removed once the full path is included in VCAP_SERVICES see issue 58873498
+        JavaBuildpack::Util::Cache::InternetAvailability.instance.available(true, 'The Spring Insight download location is always accessible') do
+          download(@version, @uri.chomp('/') + AGENT_DOWNLOAD_URI_SUFFIX) { |file| expand file } # TODO: AGENT_DOWNLOAD_URI_SUFFIX To be removed once the full path is included in VCAP_SERVICES see issue 58873498
+        end
       end
 
       # (see JavaBuildpack::Component::BaseComponent#release)

lib/java_buildpack/util/cache/internet_availability.rb

@@ -47,10 +47,20 @@ def available?
         #
         # @param [Boolean] available whether the internet is available
         # @param [String, nil] message an optional message to be printed when the availability is set
+        # @yields an environment with internet availability temporarily overridden if block given
         def available(available, message = nil)
           @monitor.synchronize do
-            @available = available
-            @logger.warn { "Internet availability set to #{available}: #{message}" } if message
+            if block_given?
+              preserve_availability do
+                @available = available
+                @logger.warn { "Internet availability temporarily set to #{available}: #{message}" } if message
+
+                yield
+              end
+            else
+              @available = available
+              @logger.warn { "Internet availability set to #{available}: #{message}" } if message
+            end
           end
         end
 
@@ -60,6 +70,15 @@ def remote_downloads?
           JavaBuildpack::Util::ConfigurationUtils.load('cache')['remote_downloads'] != 'disabled'
         end
 
+        def preserve_availability
+          previous = @available
+          begin
+            yield
+          ensure
+            @available = previous
+          end
+        end
+
       end
 
     end

spec/java_buildpack/framework/spring_insight_spec.rb

@@ -17,10 +17,12 @@
 require 'spec_helper'
 require 'component_helper'
 require 'fileutils'
+require 'internet_availability_helper'
 require 'java_buildpack/framework/spring_insight'
 
 describe JavaBuildpack::Framework::SpringInsight do
   include_context 'component_helper'
+  include_context 'internet_availability_helper'
 
   it 'should not detect without spring-insight-n/a service' do
     expect(component.detect).to be_nil
@@ -51,6 +53,13 @@
       expect(sandbox + 'insight/conf/insight.properties').to exist
     end
 
+    it 'should guarantee that internet access is available when downloading' do
+      expect_any_instance_of(JavaBuildpack::Util::Cache::InternetAvailability)
+      .to receive(:available).with(true, 'The Spring Insight download location is always accessible')
+
+      component.compile
+    end
+
     it 'should update JAVA_OPTS',
        app_fixture: 'framework_spring_insight' do
 

spec/java_buildpack/util/cache/internet_availability_spec.rb

@@ -55,4 +55,22 @@
     expect(log_contents).to match(/Internet availability set to false: test message/)
   end
 
+  it 'should temporarily set internet unavailable' do
+    expect(described_class.instance.available?).to be
+
+    described_class.instance.available(false) { expect(described_class.instance.available?).not_to be }
+
+    expect(described_class.instance.available?).to be
+  end
+
+  it 'should temporarily set internet available',
+     :disable_internet do
+
+    expect(described_class.instance.available?).not_to be
+
+    described_class.instance.available(true) { expect(described_class.instance.available?).to be }
+
+    expect(described_class.instance.available?).not_to be
+  end
+
 end