daemon: add host offlining by deleting the associated DNS records

.rubocop.yml

@@ -22,12 +22,18 @@ Metrics/BlockLength:
 Metrics/ClassLength:
   Enabled: false
 
+Metrics/CyclomaticComplexity:
+  Enabled: false
+
 Metrics/LineLength:
   Max: 200
 
 Metrics/MethodLength:
   Enabled: false
 
+Metrics/PerceivedComplexity:
+  Enabled: false
+
 Style/ConditionalAssignment:
   Enabled: false
 

CHANGELOG.md

@@ -10,6 +10,7 @@ IMPROVEMENTS:
 - Update dependencies, mainly `rack` to new major version 2
 - Add Ruby 2.5 support
 - Add experimental [OpenTracing](http://opentracing.io/) support with [CNCF Jaeger](https://github.com/jaegertracing/jaeger)
+- Support host offlining by deleting the associated DNS records
 
 ## 1.6.1 (October 31, 2017)
 

lib/dyndnsd.rb

@@ -141,7 +141,11 @@ module Dyndnsd
 
         hostnames.each do |hostname|
           # myips order is always deterministic
-          if Helper.changed?(hostname, myips, @db['hosts'])
+          if myips.empty? && @db['hosts'].include?(hostname)
+            @db['hosts'].delete(hostname)
+            changes << :good
+            Metriks.meter('requests.good').mark
+          elsif Helper.changed?(hostname, myips, @db['hosts'])
             @db['hosts'][hostname] = myips
             changes << :good
             Metriks.meter('requests.good').mark
@@ -180,10 +184,13 @@ module Dyndnsd
       forbidden_hostnames = hostnames - @users[user]['hosts']
       return [422, {'X-DynDNS-Response' => 'host_forbidden'}, []] if forbidden_hostnames.any?
 
+      if params['offline'] == 'YES'
+        myips = []
+      else
         myips = extract_myips(env, params)
-
         # require at least one IP to update
         return [422, {'X-DynDNS-Response' => 'host_forbidden'}, []] if myips.empty?
+      end
 
       Metriks.meter('requests.valid').mark
       Dyndnsd.logger.info "Request to update #{hostnames} to #{myips} for user #{user}"

lib/dyndnsd/helper.rb

@@ -24,7 +24,7 @@ module Dyndnsd
 
     def self.changed?(hostname, myips, hosts)
       # myips order is always deterministic
-      (!hosts.include? hostname) || (hosts[hostname] != myips)
+      ((!hosts.include? hostname) || (hosts[hostname] != myips)) && !myips.empty?
     end
 
     def self.span(operation, &block)

spec/daemon_spec.rb

@@ -167,6 +167,34 @@ describe Dyndnsd::Daemon do
     expect(last_response.body).to eq("nochg 2001:db8::1\ngood 2001:db8::1")
   end
 
+  it 'offlines a host' do
+    authorize 'test', 'secret'
+
+    get '/nic/update?hostname=foo.example.org&myip=1.2.3.4'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('good 1.2.3.4')
+
+    get '/nic/update?hostname=foo.example.org&offline=YES'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('good ')
+
+    get '/nic/update?hostname=foo.example.org&offline=YES'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('nochg ')
+
+    get '/nic/update?hostname=foo.example.org&myip=1.2.3.4'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('good 1.2.3.4')
+
+    get '/nic/update?hostname=foo.example.org&myip=1.2.3.4&offline=YES'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('good ')
+
+    get '/nic/update?hostname=foo.example.org&myip=1.2.3.4&offline=YES'
+    expect(last_response).to be_ok
+    expect(last_response.body).to eq('nochg ')
+  end
+
   it 'uses clients remote IP address if myip not specified' do
     authorize 'test', 'secret'
     get '/nic/update?hostname=foo.example.org'