From 3ac39ac2c10b2c264c5b6c46a61263e1d0d14759 Mon Sep 17 00:00:00 2001
From: Varun Puranik <vpuranik@microsoft.com>
Date: Fri, 14 Sep 2018 14:02:25 -0700
Subject: [PATCH] EdgeHub: Improve startup time (#291)

* Parallelize EdgeHub initialization

* Change default Operation timeout to 20 secs
---
 .../CloudConnection.cs                        |  2 +-
 .../EdgeHubConnection.cs                      | 29 +++++++++++--------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.CloudProxy/CloudConnection.cs b/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.CloudProxy/CloudConnection.cs
index 595cad4bf10..3f31c4348f5 100644
--- a/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.CloudProxy/CloudConnection.cs
+++ b/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.CloudProxy/CloudConnection.cs
@@ -25,7 +25,7 @@ class CloudConnection : ICloudConnection
         static readonly TimeSpan TokenExpiryBuffer = TimeSpan.FromMinutes(5); // Token is usable if it does not expire in 5 mins
         const int TokenTimeToLiveSeconds = 3600; // Unused - Token is generated by downstream clients
         const int TokenExpiryBufferPercentage = 8; // Assuming a standard token for 1 hr, we set expiry time to around 5 mins.
-        const uint OperationTimeoutMilliseconds = 1 * 60 * 1000; // 1 min
+        const uint OperationTimeoutMilliseconds = 20 * 1000; // 20 secs
         static readonly TimeSpan TokenRetryWaitTime = TimeSpan.FromSeconds(20);
 
         readonly Action<string, CloudConnectionStatus> connectionStatusChangedHandler;
diff --git a/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.Core/EdgeHubConnection.cs b/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.Core/EdgeHubConnection.cs
index 8c4d858fdaa..503be8f24fd 100644
--- a/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.Core/EdgeHubConnection.cs
+++ b/edge-hub/src/Microsoft.Azure.Devices.Edge.Hub.Core/EdgeHubConnection.cs
@@ -75,27 +75,32 @@ IDeviceScopeIdentitiesCache deviceScopeIdentitiesCache
             Preconditions.CheckNotNull(deviceScopeIdentitiesCache, nameof(deviceScopeIdentitiesCache));
 
             var edgeHubConnection = new EdgeHubConnection(
-                edgeHubCredentials.Identity as IModuleIdentity, twinManager, routeFactory,
-                twinCollectionMessageConverter, twinMessageConverter,
+                edgeHubCredentials.Identity as IModuleIdentity,
+                twinManager,
+                routeFactory,
+                twinCollectionMessageConverter,
+                twinMessageConverter,
                 versionInfo ?? VersionInfo.Empty,
                 deviceScopeIdentitiesCache
             );
 
-            IDeviceProxy deviceProxy = new EdgeHubDeviceProxy(edgeHubConnection);
-            await connectionManager.AddDeviceConnection(edgeHubCredentials.Identity, deviceProxy);            
-
-            await edgeHub.AddSubscription(edgeHubCredentials.Identity.Id, DeviceSubscription.DesiredPropertyUpdates);
-            await edgeHub.AddSubscription(edgeHubCredentials.Identity.Id, DeviceSubscription.Methods);
-
-            // Clear out all the reported devices.
-            await edgeHubConnection.ClearDeviceConnectionStatuses();
-
+            await InitEdgeHub(edgeHubConnection, connectionManager, edgeHubCredentials, edgeHub);
             connectionManager.DeviceConnected += edgeHubConnection.DeviceConnected;
             connectionManager.DeviceDisconnected += edgeHubConnection.DeviceDisconnected;
             Events.Initialized(edgeHubCredentials.Identity);
             return edgeHubConnection;
         }
 
+        static Task InitEdgeHub(EdgeHubConnection edgeHubConnection, IConnectionManager connectionManager, IClientCredentials edgeHubCredentials, IEdgeHub edgeHub)
+        {
+            IDeviceProxy deviceProxy = new EdgeHubDeviceProxy(edgeHubConnection);
+            Task addDeviceConnectionTask = connectionManager.AddDeviceConnection(edgeHubCredentials.Identity, deviceProxy);
+            Task desiredPropertyUpdatesSubscriptionTask = edgeHub.AddSubscription(edgeHubCredentials.Identity.Id, DeviceSubscription.DesiredPropertyUpdates);
+            Task methodsSubscriptionTask = edgeHub.AddSubscription(edgeHubCredentials.Identity.Id, DeviceSubscription.Methods);
+            Task clearDeviceConnectionStatusesTask = edgeHubConnection.ClearDeviceConnectionStatuses();
+            return Task.WhenAll(addDeviceConnectionTask, desiredPropertyUpdatesSubscriptionTask, methodsSubscriptionTask, clearDeviceConnectionStatusesTask);
+        }
+
         public async Task<Option<EdgeHubConfig>> GetConfig()
         {
             using (await this.edgeHubConfigLock.LockAsync())
@@ -359,7 +364,7 @@ internal async Task<DirectMethodResponse> HandleMethodInvocation(DirectMethodReq
                 {
                     Events.ErrorRefreshingServiceIdentities(e);
                     return new DirectMethodResponse(e, HttpStatusCode.InternalServerError);
-                }                                
+                }
             }
             else
             {