(maint) Add the last boot time for each pool

This commit add a redis hash where there is one key per pool, and the
stored value is the last time a VM was booted e.g. the last time
a VM went from 'pending' to 'ready'. This is also displayed in the
API as lastBoot:'2018-03-23 17:43:39 +0000'. The data can then be
used by any external system, in this case our alarming system.

lib/vmpooler/api/v1.rb

@@ -209,13 +209,15 @@ module Vmpooler
         running  = backend.scard('vmpooler__running__' + pool['name']).to_i
         pending  = backend.scard('vmpooler__pending__' + pool['name']).to_i
         max      = pool['size']
+        lastBoot = backend.hget('vmpooler__lastboot',pool['name']).to_s
         aka      = pool['alias']
 
         result[:pools][pool['name']] = {
           ready:    ready,
           running:  running,
           pending:  pending,
-          max:     max
+          max:      max,
+          lastBoot: lastBoot
         }
 
         if aka

lib/vmpooler/pool_manager.rb

@@ -33,7 +33,7 @@ module Vmpooler
         begin
           _check_pending_vm(vm, pool, timeout, provider)
         rescue => err
-          $logger.log('s', "[!] [#{pool}] '#{vm}' errored while checking a pending vm : #{err}")
+          $logger.log('s', "[!] [#{pool}] '#{vm}' #{timeout} #{provider} errored while checking a pending vm : #{err}")
           fail_pending_vm(vm, pool, timeout)
           raise
         end
@@ -89,7 +89,10 @@ module Vmpooler
         finish = format('%.2f', Time.now - Time.parse(clone_time)) if clone_time
 
         $redis.smove('vmpooler__pending__' + pool, 'vmpooler__ready__' + pool, vm)
-        $redis.hset('vmpooler__boot__' + Date.today.to_s, pool + ':' + vm, finish)
+        $redis.hset('vmpooler__boot__' + Date.today.to_s, pool + ':' + vm, finish) # maybe remove as this is never used by vmpooler itself?
+
+        # last boot time is displayed in API, and used by alarming script
+        $redis.hset('vmpooler__lastboot', pool, Time.now)
 
         $logger.log('s', "[>] [#{pool}] '#{vm}' moved from 'pending' to 'ready' queue")
       end

spec/unit/pool_manager_spec.rb

@@ -222,6 +222,12 @@ EOT
         redis.hset("vmpooler__vm__#{vm}", 'clone','iamnotparsable_asdate')
         expect{subject.move_pending_vm_to_ready(vm, pool, host)}.to raise_error(/iamnotparsable_asdate/)
       end
+
+      it 'should save the last boot time' do
+        expect(redis.hget('vmpooler__lastboot', pool)).to be(nil)
+        subject.move_pending_vm_to_ready(vm, pool, host)
+        expect(redis.hget('vmpooler__lastboot', pool)).to_not be(nil)
+      end
     end
   end