| | | 1 | | // Copyright (c) ZeroC, Inc. |
| | | 2 | | |
| | | 3 | | using Microsoft.Extensions.Logging; |
| | | 4 | | using System.Collections.Concurrent; |
| | | 5 | | using System.Diagnostics; |
| | | 6 | | |
| | | 7 | | namespace IceRpc.Locator.Internal; |
| | | 8 | | |
| | | 9 | | /// <summary>Provides extension methods for <see cref="ILogger" />. They are used by <see |
| | | 10 | | /// cref="LogServerAddressCacheDecorator"/>. |
| | | 11 | | /// </summary> |
| | | 12 | | internal static partial class ServerAddressCacheLoggerExtensions |
| | | 13 | | { |
| | | 14 | | [LoggerMessage( |
| | | 15 | | EventId = (int)LocationEventId.FoundEntry, |
| | | 16 | | EventName = nameof(LocationEventId.FoundEntry), |
| | | 17 | | Level = LogLevel.Trace, |
| | | 18 | | Message = "Found {LocationKind} '{Location}' = '{ServiceAddress}' in cache")] |
| | | 19 | | internal static partial void LogFoundEntry( |
| | | 20 | | this ILogger logger, |
| | | 21 | | string locationKind, |
| | | 22 | | Location location, |
| | | 23 | | ServiceAddress serviceAddress); |
| | | 24 | | |
| | | 25 | | [LoggerMessage( |
| | | 26 | | EventId = (int)LocationEventId.SetEntry, |
| | | 27 | | EventName = nameof(LocationEventId.SetEntry), |
| | | 28 | | Level = LogLevel.Trace, |
| | | 29 | | Message = "Set {LocationKind} '{Location}' = '{ServiceAddress}' in cache")] |
| | | 30 | | internal static partial void LogSetEntry( |
| | | 31 | | this ILogger logger, |
| | | 32 | | string locationKind, |
| | | 33 | | Location location, |
| | | 34 | | ServiceAddress serviceAddress); |
| | | 35 | | |
| | | 36 | | [LoggerMessage( |
| | | 37 | | EventId = (int)LocationEventId.RemovedEntry, |
| | | 38 | | EventName = nameof(LocationEventId.RemovedEntry), |
| | | 39 | | Level = LogLevel.Trace, |
| | | 40 | | Message = "Removed {LocationKind} '{Location}' from cache")] |
| | | 41 | | internal static partial void LogRemovedEntry( |
| | | 42 | | this ILogger logger, |
| | | 43 | | string locationKind, |
| | | 44 | | Location location); |
| | | 45 | | } |
| | | 46 | | |
| | | 47 | | /// <summary>A server address cache maintains a dictionary of location to server address(es), where the server |
| | | 48 | | /// addresses are held by a dummy service address. It also keeps track of the insertion time of each entry. It's |
| | | 49 | | /// consumed by <see cref="LocationResolver" />.</summary> |
| | | 50 | | internal interface IServerAddressCache |
| | | 51 | | { |
| | | 52 | | void Remove(Location location); |
| | | 53 | | |
| | | 54 | | void Set(Location location, ServiceAddress serviceAddress); |
| | | 55 | | |
| | | 56 | | bool TryGetValue(Location location, out (TimeSpan InsertionTime, ServiceAddress ServiceAddress) value); |
| | | 57 | | } |
| | | 58 | | |
| | | 59 | | /// <summary>The main implementation for <see cref="IServerAddressCache" />.</summary> |
| | | 60 | | internal sealed class ServerAddressCache : IServerAddressCache |
| | | 61 | | { |
| | | 62 | | private readonly ConcurrentDictionary<Location, (TimeSpan InsertionTime, ServiceAddress ServiceAddress, LinkedListNo |
| | | 63 | | |
| | | 64 | | // The keys in _cache. The first entries correspond to the most recently added cache entries. |
| | 6 | 65 | | private readonly LinkedList<Location> _cacheKeys = new(); |
| | | 66 | | |
| | | 67 | | private readonly int _maxCacheSize; |
| | | 68 | | |
| | | 69 | | // _mutex protects _cacheKeys and updates to _cache |
| | 6 | 70 | | private readonly object _mutex = new(); |
| | | 71 | | |
| | | 72 | | public void Remove(Location location) |
| | 10 | 73 | | { |
| | 10 | 74 | | lock (_mutex) |
| | 10 | 75 | | { |
| | 10 | 76 | | if (_cache.TryRemove( |
| | 10 | 77 | | location, |
| | 10 | 78 | | out (TimeSpan InsertionTime, ServiceAddress ServiceAddress, LinkedListNode<Location> Node) entry)) |
| | 3 | 79 | | { |
| | 3 | 80 | | _cacheKeys.Remove(entry.Node); |
| | 3 | 81 | | } |
| | 10 | 82 | | } |
| | 10 | 83 | | } |
| | | 84 | | |
| | | 85 | | public void Set(Location location, ServiceAddress serviceAddress) |
| | 8 | 86 | | { |
| | 8 | 87 | | lock (_mutex) |
| | 8 | 88 | | { |
| | 8 | 89 | | Remove(location); // remove existing cache entry if present |
| | | 90 | | |
| | 8 | 91 | | _cache[location] = |
| | 8 | 92 | | (TimeSpan.FromMilliseconds(Environment.TickCount64), serviceAddress, _cacheKeys.AddFirst(location)); |
| | | 93 | | |
| | 8 | 94 | | if (_cacheKeys.Count == _maxCacheSize + 1) |
| | 1 | 95 | | { |
| | | 96 | | // drop last (oldest) entry |
| | 1 | 97 | | Remove(_cacheKeys.Last!.Value); |
| | | 98 | | |
| | 1 | 99 | | Debug.Assert(_cacheKeys.Count == _maxCacheSize); // removed the last entry |
| | 1 | 100 | | } |
| | 8 | 101 | | } |
| | 8 | 102 | | } |
| | | 103 | | |
| | | 104 | | public bool TryGetValue(Location location, out (TimeSpan InsertionTime, ServiceAddress ServiceAddress) value) |
| | 7 | 105 | | { |
| | | 106 | | // no mutex lock: _cache is a concurrent dictionary and it's ok if it's updated while we read it |
| | | 107 | | |
| | 7 | 108 | | if (_cache.TryGetValue( |
| | 7 | 109 | | location, |
| | 7 | 110 | | out (TimeSpan InsertionTime, ServiceAddress ServiceAddress, LinkedListNode<Location> Node) entry)) |
| | 3 | 111 | | { |
| | 3 | 112 | | value.InsertionTime = entry.InsertionTime; |
| | 3 | 113 | | value.ServiceAddress = entry.ServiceAddress; |
| | 3 | 114 | | return true; |
| | | 115 | | } |
| | | 116 | | else |
| | 4 | 117 | | { |
| | 4 | 118 | | value = default; |
| | 4 | 119 | | return false; |
| | | 120 | | } |
| | 7 | 121 | | } |
| | | 122 | | |
| | 6 | 123 | | internal ServerAddressCache(int maxCacheSize) |
| | 6 | 124 | | { |
| | 6 | 125 | | Debug.Assert(maxCacheSize > 0); |
| | 6 | 126 | | _maxCacheSize = maxCacheSize; |
| | 6 | 127 | | _cache = new(concurrencyLevel: 1, capacity: _maxCacheSize + 1); |
| | 6 | 128 | | } |
| | | 129 | | } |
| | | 130 | | |
| | | 131 | | /// <summary>A decorator that adds event source logging to a server address cache.</summary> |
| | | 132 | | internal class LogServerAddressCacheDecorator : IServerAddressCache |
| | | 133 | | { |
| | | 134 | | private readonly IServerAddressCache _decoratee; |
| | | 135 | | private readonly ILogger _logger; |
| | | 136 | | |
| | | 137 | | public void Remove(Location location) |
| | | 138 | | { |
| | | 139 | | _decoratee.Remove(location); |
| | | 140 | | _logger.LogRemovedEntry(location.Kind, location); |
| | | 141 | | } |
| | | 142 | | |
| | | 143 | | public void Set(Location location, ServiceAddress serviceAddress) |
| | | 144 | | { |
| | | 145 | | _decoratee.Set(location, serviceAddress); |
| | | 146 | | _logger.LogSetEntry(location.Kind, location, serviceAddress); |
| | | 147 | | } |
| | | 148 | | |
| | | 149 | | public bool TryGetValue( |
| | | 150 | | Location location, |
| | | 151 | | out (TimeSpan InsertionTime, ServiceAddress ServiceAddress) value) |
| | | 152 | | { |
| | | 153 | | if (_decoratee.TryGetValue(location, out value)) |
| | | 154 | | { |
| | | 155 | | _logger.LogFoundEntry(location.Kind, location, value.ServiceAddress); |
| | | 156 | | return true; |
| | | 157 | | } |
| | | 158 | | else |
| | | 159 | | { |
| | | 160 | | return false; |
| | | 161 | | } |
| | | 162 | | } |
| | | 163 | | |
| | | 164 | | internal LogServerAddressCacheDecorator(IServerAddressCache decoratee, ILogger logger) |
| | | 165 | | { |
| | | 166 | | _decoratee = decoratee; |
| | | 167 | | _logger = logger; |
| | | 168 | | } |
| | | 169 | | } |