Move caching for servers to store layer.

Giants.Services/Services/ServerRegistryService.cs

@@ -16,24 +16,16 @@
         private readonly ILogger<ServerRegistryService> logger;
         private readonly IServerRegistryStore registryStore;
         private readonly IConfiguration configuration;
-        private readonly IDateTimeProvider dateTimeProvider;
-        private readonly IMemoryCache memoryCache;
-        private readonly TimeSpan timeoutPeriod;
         private readonly int maxServerCount;
 
         public ServerRegistryService(
             ILogger<ServerRegistryService> logger,
             IServerRegistryStore registryStore,
-            IConfiguration configuration,
-            IDateTimeProvider dateTimeProvider,
-            IMemoryCache memoryCache)
+            IConfiguration configuration)
         {
             this.logger = logger;
             this.registryStore = registryStore;
             this.configuration = configuration;
-            this.dateTimeProvider = dateTimeProvider;
-            this.memoryCache = memoryCache;
-            this.timeoutPeriod = TimeSpan.FromMinutes(Convert.ToDouble(this.configuration["ServerTimeoutPeriodInMinutes"]));
             this.maxServerCount = Convert.ToInt32(this.configuration["MaxServerCount"]);
         }
 
@@ -48,41 +40,13 @@
                 throw new ArgumentException($"Unsupported game name {serverInfo.GameName}", nameof(serverInfo));
             }
 
-            // Check cache before we write to store
-            ConcurrentDictionary<string, ServerInfo> allServerInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
-
-            if (allServerInfo.ContainsKey(serverInfo.HostIpAddress))
-            {
-                if (allServerInfo[serverInfo.HostIpAddress].Equals(serverInfo))
-                {
-                    this.logger.LogInformation("State for {IPAddress} is unchanged. Skipping write to store.", serverInfo.HostIpAddress);
-                    return;
-                }
-                else
-                {
-                    this.logger.LogInformation("State for {IPAddress} has changed. Committing update to store.", serverInfo.HostIpAddress);
-                }
-
-            }
             await this.registryStore.UpsertServerInfo(serverInfo);
-
-            this.logger.LogInformation("Updating cache for request from {IPAddress}.", serverInfo.HostIpAddress);
-
-            if (allServerInfo.ContainsKey(serverInfo.HostIpAddress))
-            { 
-                allServerInfo[serverInfo.HostIpAddress] = serverInfo;
-            }
-            else
-            {
-                allServerInfo.TryAdd(serverInfo.HostIpAddress, serverInfo);
-            }
         }
 
         public async Task<IEnumerable<ServerInfo>> GetAllServers()
         {
-            ConcurrentDictionary<string, ServerInfo> serverInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
-
-            return serverInfo.Values;
+            return (await this.registryStore.GetServerInfos())
+                .Take(this.maxServerCount);
         }
 
         public async Task DeleteServer(string ipAddress)
@@ -96,17 +60,5 @@
                 await this.registryStore.DeleteServer(serverInfo.id);
             }
         }
-
-        private async Task<ConcurrentDictionary<string, ServerInfo>> PopulateCache(ICacheEntry entry)
-        {
-            entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(1);
-
-            IDictionary<string, ServerInfo> serverInfo = (await this.registryStore
-                .GetServerInfos(whereExpression: c => c.LastHeartbeat > this.dateTimeProvider.UtcNow - this.timeoutPeriod))
-                .Take(this.maxServerCount)
-                .ToDictionary(x => x.HostIpAddress, y => y);
-
-            return new ConcurrentDictionary<string, ServerInfo>(serverInfo);
-        }
     }
 }

Giants.Services/Store/CosmosDbServerRegistryStore.cs

@@ -1,10 +1,14 @@
 namespace Giants.Services
 {
     using System;
+    using System.Collections.Concurrent;
     using System.Collections.Generic;
+    using System.Linq;
     using System.Linq.Expressions;
     using System.Threading.Tasks;
+    using Giants.Services.Core;
     using Microsoft.Azure.Cosmos;
+    using Microsoft.Extensions.Caching.Memory;
     using Microsoft.Extensions.Configuration;
     using Microsoft.Extensions.Logging;
 
@@ -12,21 +16,41 @@
     {
         private readonly ILogger<CosmosDbServerRegistryStore> logger;
         private readonly IConfiguration configuration;
+        private readonly IMemoryCache memoryCache;
+        private readonly IDateTimeProvider dateTimeProvider;
+        private readonly TimeSpan timeoutPeriod;
         private CosmosDbClient client;
         
         public CosmosDbServerRegistryStore(
             ILogger<CosmosDbServerRegistryStore> logger,
-            IConfiguration configuration)
+            IConfiguration configuration,
+            IMemoryCache memoryCache,
+            IDateTimeProvider dateTimeProvider)
         {
             this.logger = logger;
             this.configuration = configuration;
+            this.memoryCache = memoryCache;
+            this.dateTimeProvider = dateTimeProvider;
+            this.timeoutPeriod = TimeSpan.FromMinutes(Convert.ToDouble(this.configuration["ServerTimeoutPeriodInMinutes"]));
         }
 
         public async Task<IEnumerable<ServerInfo>> GetServerInfos(
             Expression<Func<ServerInfo, bool>> whereExpression = null,
             string partitionKey = null)
         {
-            return await this.client.GetItems<ServerInfo>(whereExpression);
+            ConcurrentDictionary<string, ServerInfo> serverInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
+
+            IQueryable<ServerInfo> serverInfoQuery = serverInfo
+                .Values
+                .AsQueryable();
+
+            if (whereExpression != null)
+            {
+                serverInfoQuery = serverInfoQuery.Where(whereExpression);
+            }
+
+            return serverInfoQuery.Where(c => c.LastHeartbeat > this.dateTimeProvider.UtcNow - this.timeoutPeriod)
+                .ToList();
         }
 
         public async Task<IEnumerable<TSelect>> GetServerInfos<TSelect>(
@@ -34,18 +58,40 @@
             Expression<Func<ServerInfo, bool>> whereExpression = null,
             string partitionKey = null)
         {
-            ArgumentUtility.CheckForNull(selectExpression, nameof(selectExpression));
+            ConcurrentDictionary<string, ServerInfo> serverInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
 
-            return await this.client.GetItems<ServerInfo, TSelect>(
-                selectExpression: selectExpression,
-                whereExpression: whereExpression,
-                partitionKey: partitionKey);
+            IQueryable<ServerInfo> serverInfoQuery = serverInfo
+                .Values
+                .AsQueryable();
+
+            if (serverInfoQuery != null)
+            {
+                serverInfoQuery = serverInfoQuery.Where(whereExpression);
+            }
+
+            return serverInfoQuery.Where(c => c.LastHeartbeat > this.dateTimeProvider.UtcNow - this.timeoutPeriod)
+                .Select(selectExpression)
+                .ToList();
         }
 
         public async Task<ServerInfo> GetServerInfo(string ipAddress)
         {
             ArgumentUtility.CheckStringForNullOrEmpty(ipAddress, nameof(ipAddress));
 
+            ConcurrentDictionary<string, ServerInfo> serverInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
+            if (serverInfo.ContainsKey(ipAddress))
+            {
+                try
+                { 
+                    return serverInfo[ipAddress];
+                }
+                catch (Exception e)
+                {
+                    this.logger.LogInformation("Cached server for {IPAddress} no longer found: {Exception}", ipAddress, e.ToString());
+                    // May have been removed from the cache by another thread. Ignore and query DB instead.
+                }
+            }
+
             return await this.client.GetItemById<ServerInfo>(ipAddress);
         }
 
@@ -53,14 +99,45 @@
         {
             ArgumentUtility.CheckForNull(serverInfo, nameof(serverInfo));
 
+            // Check cache before we write to store
+            ConcurrentDictionary<string, ServerInfo> allServerInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
+
+            if (allServerInfo.ContainsKey(serverInfo.HostIpAddress))
+            {
+                if (allServerInfo[serverInfo.HostIpAddress].Equals(serverInfo))
+                {
+                    this.logger.LogInformation("State for {IPAddress} is unchanged. Skipping write to store.", serverInfo.HostIpAddress);
+                    return;
+                }
+                else
+                {
+                    this.logger.LogInformation("State for {IPAddress} has changed. Committing update to store.", serverInfo.HostIpAddress);
+                }
+            }
+
             await this.client.UpsertItem(
                 item: serverInfo,
                 partitionKey: new PartitionKey(serverInfo.DocumentType));
+
+            this.logger.LogInformation("Updating cache for request from {IPAddress}.", serverInfo.HostIpAddress);
+
+            if (allServerInfo.ContainsKey(serverInfo.HostIpAddress))
+            {
+                allServerInfo[serverInfo.HostIpAddress] = serverInfo;
+            }
+            else
+            {
+                allServerInfo.TryAdd(serverInfo.HostIpAddress, serverInfo);
+            }
         }
 
         public async Task DeleteServer(string id, string partitionKey = null)
         {
             await this.client.DeleteItem<ServerInfo>(id, partitionKey);
+
+            // Remove from cache
+            ConcurrentDictionary<string, ServerInfo> allServerInfo = await this.memoryCache.GetOrCreateAsync(CacheKeys.ServerInfo, this.PopulateCache);
+            allServerInfo.TryRemove(id, out ServerInfo _);
         }
 
         public async Task DeleteServers(IEnumerable<string> ids, string partitionKey = null)
@@ -71,7 +148,7 @@
             { 
                 this.logger.LogInformation("Deleting server for host IP {IPAddress}", id);
 
-                await this.client.DeleteItem<ServerInfo>(id, partitionKey);
+                await this.DeleteServer(id, partitionKey);
             }
         }
 
@@ -85,5 +162,16 @@
 
             await this.client.Initialize();
         }
+
+        private async Task<ConcurrentDictionary<string, ServerInfo>> PopulateCache(ICacheEntry entry)
+        {
+            entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(1);
+
+            IDictionary<string, ServerInfo> serverInfo = 
+                (await this.client.GetItems<ServerInfo>())
+                .ToDictionary(x => x.HostIpAddress, y => y);
+
+            return new ConcurrentDictionary<string, ServerInfo>(serverInfo);
+        }
     }
 }

Giants.WebApi/Properties/launchSettings.json

@@ -1,5 +1,4 @@
-{
-  "$schema": "http://json.schemastore.org/launchsettings.json",
+{
   "iisSettings": {
     "windowsAuthentication": false,
     "anonymousAuthentication": true,
@@ -8,11 +7,11 @@
       "sslPort": 44304
     }
   },
+  "$schema": "http://json.schemastore.org/launchsettings.json",
   "profiles": {
     "IIS Express": {
       "commandName": "IISExpress",
       "launchBrowser": true,
-      "launchUrl": "weatherforecast",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
       }
@@ -21,10 +20,10 @@
       "commandName": "Project",
       "launchBrowser": true,
       "launchUrl": "weatherforecast",
-      "applicationUrl": "https://localhost:5001;http://localhost:5000",
       "environmentVariables": {
         "ASPNETCORE_ENVIRONMENT": "Development"
-      }
+      },
+      "applicationUrl": "https://localhost:5001;http://localhost:5000"
     }
   }
-}
+}