system:put : first success

jmettraux · Mar 9, 2011 · 813741f · 813741f
1 parent 33f2e93
commit 813741f
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Showing 3 changed files with 61 additions and 48 deletions.
diff --git a/lib/register/system.rb b/lib/register/system.rb
@@ -33,56 +33,64 @@ def self.put_system(redis)
         '_id' => 'system',
         '_rev' => '0',
 
-        'set' => proc { |args|
+        'put' => proc { |item|
-          @redis.set(args['key'], Rufus::Json.encode(args['value']))
+          rev = item['_rev']
+          Register.lock(@redis, item['_id']) do
+            current = @redis.get(item['_id'])
+            current_rev = current ? current['_rev'] : nil
+            if current_rev && rev != current_rev
+              current
+            elsif rev && current_rev.nil?
+              false
+            else
+              nrev = (rev || 0) + 1
+              @redis.set(
+                item['_id'],
+                Rufus::Json.encode(item.merge('_rev' => nrev)))
+              nrev
+            end
+          end
         }.to_source,
 
-        #'put' => proc { |args|
-        #  item = args
-        #  lock(item['_id']) do
-        #    # TODO
-        #  end
-        #}.to_source,
-
         'echo' => proc { |args|
           args.collect { |a| a.to_s }.join(' ')
         }.to_source
 
       ).to_json)
   end
 
-#  # A locking mecha.
+  # A locking mecha.
-#  #
+  #
-#  # Mostly inspired from http://code.google.com/p/redis/wiki/SetnxCommand
+  # Mostly inspired from http://code.google.com/p/redis/wiki/SetnxCommand
-#  #
+  #
-#  def self.lock(key)
+  def self.lock(redis, key)
-#
+
-#    kl = "#{key}-lock"
+    kl = "#{key}-lock"
-#
+
-#    loop do
+    loop do
-#
+
-#      break if @redis.setnx(kl, Time.now.to_f.to_s) != false
+      break if redis.setnx(kl, Time.now.to_f.to_s) != false
-#        # locking successful
+        # locking successful
-#
+
-#      #
+      #
-#      # already locked
+      # already locked
-#
+
-#      t = @redis.get(kl)
+      t = redis.get(kl)
-#
+
-#      @redis.del(kl) if t && Time.now.to_f - t.to_f > 60.0
+      redis.del(kl) if t && Time.now.to_f - t.to_f > 60.0
-#        # after 1 minute, locks time out
+        # after 1 minute, locks time out
-#
+
-#      sleep 0.007 # let's try to lock again after a while
+      sleep 0.007 # let's try to lock again after a while
-#    end
+    end
-#
+
-#    #@redis.expire(kl, 2)
+    #redis.expire(kl, 2)
-#      # this doesn't work, it makes the next call to setnx succeed
+      # this doesn't work, it makes the next call to setnx succeed
-#
+
-#    result = yield
+    result = yield
-#
+
-#    @redis.del(kl)
+    redis.del(kl)
-#
+
-#    result
+    result
-#  end
+  end
 end
 
diff --git a/lib/register/worker.rb b/lib/register/worker.rb
@@ -87,7 +87,12 @@ def step
     def reply(call, success, result)
 
       if ticket = call['ticket']
-        @client.redis.hset('_tickets', ticket, [ success, result ])
+
+        @client.redis.hset(
+          '_tickets',
+          ticket,
+          Rufus::Json.encode([ success, result ]))
+
       #else
         # no ticket given back
       end

diff --git a/spec/system_spec.rb b/spec/system_spec.rb
@@ -25,16 +25,16 @@
     end
   end
 
-  describe "'set'" do
+  describe "'put'" do
 
-    it 'sets a value' do
+    it 'puts an item' do
 
-      ticket = cl.call('system', 'set', 'key' => 'x', 'value' => %w[ y z ])
+      ticket = cl.call('system', 'put', '_id' => 'x')
 
       wo.send(:step)
 
-      cl.result(ticket).should == [ true, 'OK' ]
+      cl.result(ticket).should == [ true, 1 ]
-      @r.get('x').should == Rufus::Json.encode(%w[ y z ])
+      @r.get('x').should == Rufus::Json.encode('_id' => 'x', '_rev' => 1)
     end
   end
 end