Merge pull request #324 from puppetlabs/QENG-7201

(QENG-7201) Vmpooler pool statistic endpoint optimization

docs/API.md

@@ -629,6 +629,52 @@ The valid sections are "boot", "clone" or "tag" eg. `vmpooler.example.com/api/v1
 You can further drill-down the data by specifying the second level parameter to query eg
 `vmpooler.example.com/api/v1/summary/tag/created_by`
 
+##### GET /poolstat?pool=FOO
+
+For parameter `pool`, containing a comma separated list of pool names to query, this endpoint returns
+each of the pool's ready, max and alias information. It can be used to get a fast response for
+the required pools instead of using the /status API endpoint
+
+Return codes
+* 200  OK 
+
+```
+$ curl https://vmpooler.example.com/api/v1/poolstat?pool=centos-6-x86_64
+```
+```json
+{
+  "pools": {
+    "centos-6-x86_64": {
+      "ready": 25,
+      "max": 25,
+      "alias": [
+        "centos-6-64",
+        "centos-6-amd64"
+      ]
+    }
+  }
+}
+```
+
+##### GET /totalrunning
+
+Fast endpoint to return the total number of VMs in a 'running' state
+
+Return codes
+* 200  OK 
+
+```
+$ curl https://vmpooler.example.com/api/v1/totalrunning
+```
+
+```json
+{
+
+  "running": 362
+
+}
+```
+
 #### Managing pool configuration via API <a name="poolconfig"></a>
 
 ##### GET /config

lib/vmpooler/api/v1.rb

@@ -341,6 +341,79 @@ module Vmpooler
       JSON.pretty_generate(Hash[result.sort_by { |k, _v| k }])
     end
 
+    # request statistics for specific pools by passing parameter 'pool'
+    # with a coma separated list of pools we want to query ?pool=ABC,DEF
+    # returns the ready, max numbers and the aliases (if set)
+    get "#{api_prefix}/poolstat/?" do
+      content_type :json
+
+      result = {}
+
+      poolscopy = []
+
+      if params[:pool]
+        subpool = params[:pool].split(",")
+        poolscopy = pools.select do |p|
+          if subpool.include?(p['name'])
+            true
+          elsif !p['alias'].nil?
+            if p['alias'].is_a?(Array)
+              (p['alias'] & subpool).any?
+            elsif p['alias'].is_a?(String)
+              subpool.include?(p['alias'])
+            end
+          end
+        end
+      end
+
+      result[:pools] = {}
+
+      poolscopy.each do |pool|
+        result[:pools][pool['name']] = {}
+
+        max      = pool['size']
+        aka      = pool['alias']
+
+        result[:pools][pool['name']][:max] = max
+
+        if aka
+          result[:pools][pool['name']][:alias] = aka
+        end
+
+      end
+
+      # using pipelined is much faster than querying each of the pools
+      res = backend.pipelined do
+        poolscopy.each do |pool|
+          backend.scard('vmpooler__ready__' + pool['name'])
+        end
+      end
+
+      res.each_with_index { |ready, i| result[:pools][poolscopy[i]['name']][:ready] = ready }
+
+      JSON.pretty_generate(Hash[result.sort_by { |k, _v| k }])
+    end
+
+    # requests the total number of running VMs
+    get "#{api_prefix}/totalrunning/?" do
+      content_type :json
+      queue = {
+          running:   0,
+      }
+
+      # using pipelined is much faster than querying each of the pools and adding them
+      # as we get the result.
+      res = backend.pipelined do
+        pools.each do |pool|
+          backend.scard('vmpooler__running__' + pool['name'])
+        end
+      end
+
+      queue[:running] = res.inject(0){ |m, x| m+x }
+
+      JSON.pretty_generate(queue)
+    end
+
     get "#{api_prefix}/summary/?" do
       content_type :json
 

spec/integration/api/v1/status_spec.rb

@@ -12,7 +12,7 @@ describe Vmpooler::API::V1 do
     Vmpooler::API
   end
 
-  describe '/status' do
+  describe 'status and metrics endpoints' do
     let(:prefix) { '/api/v1' }
 
     let(:config) {
@@ -186,5 +186,55 @@ describe Vmpooler::API::V1 do
         expect(result["status"]).to_not be(nil)
       end
     end
+
+    describe 'GET /poolstat' do
+      it 'returns empty list when pool is not set' do
+        get "#{prefix}/poolstat"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result  == {})
+      end
+      it 'returns empty list when pool is not found' do
+        get "#{prefix}/poolstat?pool=unknownpool"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result  == {})
+      end
+      it 'returns one pool when requesting one with alias' do
+        get "#{prefix}/poolstat?pool=pool1"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"].size == 1)
+        expect(result["pools"]["pool1"]["ready"]).to eq(0)
+        expect(result["pools"]["pool1"]["max"]).to eq(5)
+        expect(result["pools"]["pool1"]["alias"]).to eq(['poolone', 'poolun'])
+      end
+      it 'returns one pool when requesting one without alias' do
+        get "#{prefix}/poolstat?pool=pool2"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"].size == 1)
+        expect(result["pools"]["pool2"]["ready"]).to eq(0)
+        expect(result["pools"]["pool2"]["max"]).to eq(10)
+        expect(result["pools"]["pool2"]["alias"]).to be(nil)
+      end
+      it 'returns multiple pools when requesting csv' do
+        get "#{prefix}/poolstat?pool=pool1,pool2"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"].size == 2)
+      end
+    end
+
+    describe 'GET /totalrunning' do
+      it 'returns the number of running VMs' do
+        get "#{prefix}/totalrunning"
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        5.times {|i| create_running_vm("pool1", "vm-#{i}") }
+        5.times {|i| create_running_vm("pool3", "vm-#{i}") }
+        result = JSON.parse(last_response.body)
+        expect(result["running"] == 10)
+      end
+    end
   end
 end