RUBY-1874 Add "connectionError" as a valid "reason" for a ConnectionC…

…heckOutFailedEvent when connection set up fails (#1453)

* Add connectionError as a valid reason for a ConnectionCheckOutFailedEvent when connection setup fails

* Start populator after pool created event is emitted to enforce cmap event order

* use authorized client instead of local

lib/mongo/server/connection_pool.rb

@@ -127,11 +127,11 @@ def initialize(server, options = {})
 
         ObjectSpace.define_finalizer(self, self.class.finalize(@available_connections, @pending_connections, @populator))
 
-        @populator.run! if min_size > 0
-
         publish_cmap_event(
           Monitoring::Event::Cmap::PoolCreated.new(@server.address, options)
         )
+
+        @populator.run! if min_size > 0
       end
 
       # @return [ Hash ] options The pool options.
@@ -243,17 +243,26 @@ def closed?
       # checked back in via the check_in method.
       #
       # @return [ Mongo::Server::Connection ] The checked out connection.
+      # @raise [ Error::PoolClosedError ] If the pool has been closed.
       # @raise [ Timeout::Error ] If the connection pool is at maximum size
       #   and remains so for longer than the wait timeout.
       #
       # @since 2.9.0
       def check_out
-        raise_if_closed!
-
         publish_cmap_event(
           Monitoring::Event::Cmap::ConnectionCheckOutStarted.new(@server.address)
         )
 
+        if closed?
+          publish_cmap_event(
+            Monitoring::Event::Cmap::ConnectionCheckOutFailed.new(
+              @server.address,
+              Monitoring::Event::Cmap::ConnectionCheckOutFailed::POOL_CLOSED
+            ),
+          )
+          raise Error::PoolClosedError.new(@server.address)
+        end
+
         deadline = Time.now + wait_timeout
         connection = nil
         # It seems that synchronize sets up its own loop, thus a simple break

spec/mongo/server/connection_pool_populator_spec.rb

@@ -246,15 +246,15 @@
     context 'when populate encounters a network error twice' do
       it 'retries once and does not stop the populator' do
         expect(pool).to receive(:create_and_add_connection).twice.and_raise(Mongo::Error::SocketError)
-        sleep 0.5
+        sleep 2
         expect(pool.instance_variable_get('@populator').running?).to be true
       end
     end
 
     context 'when populate encounters a non-network error' do
       it 'does not retry and does not stop the populator' do
         expect(pool).to receive(:create_and_add_connection).and_raise(Mongo::Error)
-        sleep 0.5
+        sleep 2
         expect(pool.instance_variable_get('@populator').running?).to be true
       end
     end

spec/mongo/server/connection_pool_spec.rb

@@ -497,6 +497,34 @@
         end.to raise_error(Mongo::Error::PoolClosedError)
       end
     end
+
+    context 'when connection set up throws an error during check out' do
+      let(:client) do
+        authorized_client
+      end
+
+       let(:pool) do
+        client.cluster.next_primary.pool
+      end
+
+       it 'raises an error and emits ConnectionCheckOutFailedEvent' do
+        pool
+
+        subscriber = EventSubscriber.new
+        client.subscribe(Mongo::Monitoring::CONNECTION_POOL, subscriber)
+
+        subscriber.clear_events!
+        expect(Mongo::Auth).to receive(:get).at_least(:once).and_raise(Mongo::Error)
+        expect { pool.check_out }.to raise_error(Mongo::Error)
+        expect(pool.size).to eq(0)
+
+         checkout_failed_events = subscriber.published_events.select do |event|
+          event.is_a?(Mongo::Monitoring::Event::Cmap::ConnectionCheckOutFailed)
+        end
+        expect(checkout_failed_events.size).to eq(1)
+        expect(checkout_failed_events.first.reason).to be(:connection_error)
+      end
+    end
   end
 
   describe '#disconnect!' do

spec/spec_tests/data/cmap/pool-checkout-error-closed.yml

@@ -15,14 +15,17 @@ events:
   - type: ConnectionPoolCreated
     address: 42
     options: 42
+  - type: ConnectionCheckOutStarted
   - type: ConnectionCheckedOut
     connectionId: 42
   - type: ConnectionCheckedIn
     connectionId: 42
   - type: ConnectionPoolClosed
     address: 42
+  - type: ConnectionCheckOutStarted
+  - type: ConnectionCheckOutFailed
+    reason: poolClosed
 ignore:
   - ConnectionCreated
   - ConnectionReady
   - ConnectionClosed
-  - ConnectionCheckOutStarted