Add hosts resolver, and add test for DNS timeouts

sensu-plugins · Feb 17, 2019 · e671314 · e671314
1 parent a13a0ec
commit e671314
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Showing 2 changed files with 19 additions and 6 deletions.
diff --git a/bin/check-http.rb b/bin/check-http.rb
@@ -181,6 +181,12 @@ class CheckHttp < Sensu::Plugin::Check::CLI
          description: 'Number of seconds to wait for one block to be read',
          default: 15
 
+  option :dns_timeout,
+         long: '--dns-timeout SECS',
+         proc: proc(&:to_f),
+         description: 'Number of seconds to allow for DNS resolution. Accepts decimal number.',
+         default: 0.8
+
   option :redirectok,
          short: '-r',
          boolean: true,
@@ -263,10 +269,11 @@ def run
       config[:port] ||= config[:ssl] ? 443 : 80
     end
 
-    # Use Ruby DNS Resolver and set DNS resolution timeout to 800ms
+    # Use Ruby DNS Resolver and set DNS resolution timeout to dns_timeout value
+    hosts_resolver = Resolv::Hosts.new
     dns_resolver = Resolv::DNS.new
-    dns_resolver.timeouts = 0.8
-    Resolv::DefaultResolver.replace_resolvers([dns_resolver])
+    dns_resolver.timeouts = config[:dns_timeout]
+    Resolv::DefaultResolver.replace_resolvers([hosts_resolver, dns_resolver])
 
     begin
       Timeout.timeout(config[:timeout]) do

diff --git a/test/integration/helpers/serverspec/check-http-shared_spec.rb b/test/integration/helpers/serverspec/check-http-shared_spec.rb
@@ -6,7 +6,7 @@
 gem_path = '/usr/local/bin'
 check_name = 'check-http.rb'
 check = "#{gem_path}/#{check_name}"
-domain = 'localhost'
+domain = '127.0.0.1'
 
 describe 'ruby environment' do
   it_behaves_like 'ruby checks', check
@@ -40,8 +40,14 @@
 describe command("#{check} --url https://#{domain}/okay") do
   its(:exit_status) { should eq 2 }
   if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.3.0')
-    its(:stdout) { should match(/CheckHttp CRITICAL: Request error: Failed to open TCP connection to localhost:443/) }
+    its(:stdout) { should match(/CheckHttp CRITICAL: Request error: Failed to open TCP connection to 127.0.0.1:443/) }
   else
-    its(:stdout) { should match(/CheckHttp CRITICAL: Request error: Cannot assign requested address - connect\(2\) for "localhost" port 443/) }
+    its(:stdout) { should match(/CheckHttp CRITICAL: Request error: Cannot assign requested address - connect\(2\) for "127.0.0.1" port 443/) }
   end
 end
+
+# DNS timeout
+describe command("#{check} --url http://blackhole.webpagetest.org/okay --dns-timeout 0.00001") do
+  its(:exit_status) { should eq 2 }
+  its(:stdout) { should match(/CheckHttp CRITICAL: Request error: Failed to open TCP connection to blackhole.webpagetest.org/) }
+end