Commit WIP

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-resolution-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,
@@ -263,15 +269,21 @@ 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])
+    resolved_hostname = Resolv.getaddress(config[:host])
 
     begin
       Timeout.timeout(config[:timeout]) do
-        acquire_resource
+        acquire_resource(resolved_hostname)
       end
+    rescue Resolv::ResolvTimeout
+      critical 'Timed out resolving DNS'
+    rescue Resolv::ResolvError => e
+      critical "Unable to resolve DNS: #{e.message}"
     rescue Net::OpenTimeout
       critical 'Request timed out opening connection'
     rescue Net::ReadTimeout
@@ -283,23 +295,23 @@ def run
     end
   end
 
-  def acquire_resource
+  def acquire_resource(endpoint)
     http = nil
 
     if config[:no_proxy]
-      http = Net::HTTP.new(config[:host], config[:port], nil, nil)
+      http = Net::HTTP.new(endpoint, config[:port], nil, nil)
     elsif config[:proxy_url]
       proxy_uri = URI.parse(config[:proxy_url])
       if proxy_uri.host.nil?
         unknown 'Invalid proxy url specified'
       end
       http = if proxy_uri.user && proxy_uri.password
-               Net::HTTP.new(config[:host], config[:port], proxy_uri.host, proxy_uri.port, proxy_uri.user, proxy_uri.password)
+               Net::HTTP.new(endpoint, config[:port], proxy_uri.host, proxy_uri.port, proxy_uri.user, proxy_uri.password)
              else
-               Net::HTTP.new(config[:host], config[:port], proxy_uri.host, proxy_uri.port)
+               Net::HTTP.new(endpoint, config[:port], proxy_uri.host, proxy_uri.port)
              end
     else
-      http = Net::HTTP.new(config[:host], config[:port])
+      http = Net::HTTP.new(endpoint, config[:port])
     end
     http.read_timeout = config[:read_timeout]
     http.open_timeout = config[:open_timeout]
@@ -333,11 +345,11 @@ def acquire_resource
 
     req = case config[:method]
           when 'GET'
-            Net::HTTP::Get.new(config[:request_uri], 'User-Agent' => config[:ua])
+            Net::HTTP::Get.new(config[:request_uri], 'User-Agent' => config[:ua], 'Host' => config[:host])
           when 'POST'
-            Net::HTTP::Post.new(config[:request_uri], 'User-Agent' => config[:ua])
+            Net::HTTP::Post.new(config[:request_uri], 'User-Agent' => config[:ua], 'Host' => config[:host])
           when 'PUT'
-            Net::HTTP::Put.new(config[:request_uri], 'User-Agent' => config[:ua])
+            Net::HTTP::Put.new(config[:request_uri], 'User-Agent' => config[:ua], 'Host' => config[:host])
           end
 
     unless config[:user].nil? && config[:password].nil?

test/integration/helpers/serverspec/check-http-shared_spec.rb

@@ -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://nonexistantdomain/okay --dns-resolution-timeout 0.0001") do
+  its(:exit_status) { should eq 2 }
+  its(:stdout) { should match(/CheckHttp CRITICAL: Timed out resolving DNS/) }
+end