[QENG-4181] Add per-pool stats to /status API

Prior to this the only per-pool statistics that could be extracted from the API
were a list of empty pools in the "status" section of the returned results of
the `/status` endpoint.

This adds a new "pools" section to the '/status' results which lists, for each
pool, the following results:

 - The number of ready vms in the pool
 - The number of running vms in the pool
 - The number of pending vms in the pool
 - The maximum size of the pool (as specified in the vmpooler configuration)

Example:

```
{
  "boot": {
  "duration": {
    "average": 163.6,
    "min": 65.49,
    "max": 830.07,
    "total": 247744.71000000002
  },
  "count": {
    "total": 1514
  }
  # ...
  "pools": {
    "pool1": {
      "ready":   5,
      "running": 2,
      "pending": 1,
      "max":     15
    },
    "pool2": {
      "ready":   0,
      "running": 10,
      "pending": 0,
      "max:      10
    }
  }
}
```

This includes spec coverage for this change (we could use more specs on `/status` in general); as well as a couple of general spec improvements.

spec/helpers.rb

@@ -35,8 +35,7 @@ end
 def create_ready_vm(template, name, token = nil)
   create_vm(name, token)
   redis.sadd("vmpooler__ready__#{template}", name)
-  # REMIND: should be __vm__?
-  redis.hset("vmpooler_vm_#{name}", "template", template)
+  redis.hset("vmpooler__vm__#{name}", "template", template)
 end
 
 def create_running_vm(template, name, token = nil)
@@ -45,6 +44,12 @@ def create_running_vm(template, name, token = nil)
   redis.hset("vmpooler__vm__#{name}", "template", template)
 end
 
+def create_pending_vm(template, name, token = nil)
+  create_vm(name, token)
+  redis.sadd("vmpooler__pending__#{template}", name)
+  redis.hset("vmpooler__vm__#{name}", "template", template)
+end
+
 def create_vm(name, token = nil)
   redis.hset("vmpooler__vm__#{name}", 'checkout', Time.now)
   if token

spec/vmpooler/api/v1/status_spec.rb

@@ -0,0 +1,111 @@
+require 'spec_helper'
+require 'rack/test'
+
+module Vmpooler
+  class API
+    module Helpers
+      def authenticate(auth, username_str, password_str)
+        username_str == 'admin' and password_str == 's3cr3t'
+      end
+    end
+  end
+end
+
+def has_set_tag?(vm, tag, value)
+  value == redis.hget("vmpooler__vm__#{vm}", "tag:#{tag}")
+end
+
+describe Vmpooler::API::V1 do
+  include Rack::Test::Methods
+
+  def app()
+    Vmpooler::API
+  end
+
+  describe '/status' do
+    let(:prefix) { '/api/v1' }
+
+    let(:config) {
+      {
+        config: {
+          'site_name' => 'test pooler',
+          'vm_lifetime_auth' => 2,
+        },
+        pools: [
+          {'name' => 'pool1', 'size' => 5},
+          {'name' => 'pool2', 'size' => 10}
+        ],
+        alias: { 'poolone' => 'pool1' },
+      }
+    }
+
+    let(:current_time) { Time.now }
+
+    before(:each) do
+      redis.flushdb
+
+      app.settings.set :config, config
+      app.settings.set :redis, redis
+      app.settings.set :config, auth: false
+      create_token('abcdefghijklmnopqrstuvwxyz012345', 'jdoe', current_time)
+    end
+
+    describe 'GET /status' do
+      it 'returns the configured maximum size for each pool' do
+        get "#{prefix}/status/"
+
+        # of course /status doesn't conform to the weird standard everything else uses...
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"]["pool1"]["max"]).to be(5)
+        expect(result["pools"]["pool2"]["max"]).to be(10)
+      end
+
+      it 'returns the number of ready vms for each pool' do
+        3.times {|i| create_ready_vm("pool1", "vm-#{i}") }
+        get "#{prefix}/status/"
+
+        # of course /status doesn't conform to the weird standard everything else uses...
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"]["pool1"]["ready"]).to be(3)
+        expect(result["pools"]["pool2"]["ready"]).to be(0)
+      end
+
+      it 'returns the number of running vms for each pool' do
+        3.times {|i| create_running_vm("pool1", "vm-#{i}") }
+        4.times {|i| create_running_vm("pool2", "vm-#{i}") }
+
+        get "#{prefix}/status/"
+
+        # of course /status doesn't conform to the weird standard everything else uses...
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"]["pool1"]["running"]).to be(3)
+        expect(result["pools"]["pool2"]["running"]).to be(4)
+      end
+
+      it 'returns the number of pending vms for each pool' do
+        3.times {|i| create_pending_vm("pool1", "vm-#{i}") }
+        4.times {|i| create_pending_vm("pool2", "vm-#{i}") }
+
+        get "#{prefix}/status/"
+
+        # of course /status doesn't conform to the weird standard everything else uses...
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["pools"]["pool1"]["pending"]).to be(3)
+        expect(result["pools"]["pool2"]["pending"]).to be(4)
+      end
+
+      it '(for v1 backwards compatibility) lists any empty pools in the status section' do
+        get "#{prefix}/status/"
+
+        # of course /status doesn't conform to the weird standard everything else uses...
+        expect(last_response.header['Content-Type']).to eq('application/json')
+        result = JSON.parse(last_response.body)
+        expect(result["status"]["empty"].sort).to eq(["pool1", "pool2"])
+      end
+    end
+  end
+end