Improve checkout page load time by fetching recommended fee in the ba…

…ckground periodically
btcpayserver · Jan 18, 2024 · 23d6e0f · 23d6e0f
1 parent 3eec9cb
commit 23d6e0f
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Showing 4 changed files with 52 additions and 7 deletions.
diff --git a/BTCPayServer.Tests/ThirdPartyTests.cs b/BTCPayServer.Tests/ThirdPartyTests.cs
@@ -91,7 +91,13 @@ public async Task CanQueryMempoolFeeProvider()
                     "test" + isTestnet,
                     prov.GetService<IHttpClientFactory>(),
                     isTestnet);
+                mempoolSpaceFeeProvider.CachedOnly = true;
+                await Assert.ThrowsAsync<InvalidOperationException>(() => mempoolSpaceFeeProvider.GetFeeRateAsync());
+                mempoolSpaceFeeProvider.CachedOnly = false;
                 var rates = await mempoolSpaceFeeProvider.GetFeeRatesAsync();
+                mempoolSpaceFeeProvider.CachedOnly = true;
+                await mempoolSpaceFeeProvider.GetFeeRateAsync();
+                mempoolSpaceFeeProvider.CachedOnly = false;
                 Assert.NotEmpty(rates);
 
 

diff --git a/BTCPayServer/Hosting/BTCPayServerServices.cs b/BTCPayServer/Hosting/BTCPayServerServices.cs
@@ -368,7 +368,8 @@ public static IServiceCollection AddBTCPayServer(this IServiceCollection service
             services.TryAddSingleton<WalletReceiveService>();
             services.AddSingleton<IHostedService>(provider => provider.GetService<WalletReceiveService>());
             services.TryAddSingleton<CurrencyNameTable>(CurrencyNameTable.Instance);
-            services.TryAddSingleton<IFeeProviderFactory, FeeProviderFactory>();
+            services.AddScheduledTask<FeeProviderFactory>(TimeSpan.FromMinutes(3.0));
+            services.AddSingleton<IFeeProviderFactory, FeeProviderFactory>(f => f.GetRequiredService<FeeProviderFactory>());
 
             services.Configure<MvcOptions>((o) =>
             {

diff --git a/BTCPayServer/Services/Fees/FeeProviderFactory.cs b/BTCPayServer/Services/Fees/FeeProviderFactory.cs
@@ -1,22 +1,26 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+using BTCPayServer.HostedServices;
 using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.Extensions.Caching.Memory;
 using NBitcoin;
 
 namespace BTCPayServer.Services.Fees;
 
-public class FeeProviderFactory : IFeeProviderFactory
+public class FeeProviderFactory : IFeeProviderFactory, IPeriodicTask
 {
     public FeeProviderFactory(
     BTCPayServerEnvironment Environment,
     ExplorerClientProvider ExplorerClients,
     IHttpClientFactory HttpClientFactory,
     IMemoryCache MemoryCache)
     {
-        _FeeProviders = new ();
+        _FeeProviders = new();
 
         // TODO: Pluginify this
         foreach ((var network, var client) in ExplorerClients.GetAll())
@@ -29,7 +33,10 @@ public class FeeProviderFactory : IFeeProviderFactory
                     $"MempoolSpaceFeeProvider-{network.CryptoCode}",
                     HttpClientFactory,
                     network is BTCPayNetwork n &&
-                    n.NBitcoinNetwork.ChainName == ChainName.Testnet));
+                    n.NBitcoinNetwork.ChainName == ChainName.Testnet)
+                {
+                    CachedOnly = true
+                });
             }
             providers.Add(new NBXplorerFeeProvider(client));
             providers.Add(new StaticFeeProvider(new FeeRate(100L, 1)));
@@ -42,4 +49,27 @@ public IFeeProvider CreateFeeProvider(BTCPayNetworkBase network)
     {
         return _FeeProviders.TryGetValue(network, out var prov) ? prov : throw new NotSupportedException($"No fee provider for this network ({network.CryptoCode})");
     }
+
+    public async Task Do(CancellationToken cancellationToken)
+    {
+        try
+        {
+            await RefreshCache(_FeeProviders.Values);
+        }
+        // Do not spam logs if mempoolspace is down
+        catch (TaskCanceledException)
+        {
+        }
+        catch (HttpRequestException)
+        {
+        }
+    }
+    private Task RefreshCache(IEnumerable<IFeeProvider> feeProviders) => Task.WhenAll(feeProviders.Select(fp => RefreshCache(fp)));
+    private Task RefreshCache(IFeeProvider fp) =>
+        fp switch
+        {
+            FallbackFeeProvider ffp => Task.WhenAll(ffp.Providers.Select(p => RefreshCache(p))),
+            MempoolSpaceFeeProvider mempool => mempool.RefreshCache(),
+            _ => Task.CompletedTask
+        };
 }
diff --git a/BTCPayServer/Services/Fees/MempoolSpaceFeeProvider.cs b/BTCPayServer/Services/Fees/MempoolSpaceFeeProvider.cs
@@ -52,14 +52,23 @@ internal static FeeRate InterpolateOrBound(BlockFeeRate[] ordered, int target)
         var a = (decimal)(target - lb.Blocks) / (decimal)(hb.Blocks - lb.Blocks);
         return new FeeRate((1 - a) * lb.FeeRate.SatoshiPerByte + a * hb.FeeRate.SatoshiPerByte);
     }
+    readonly TimeSpan Expiration = TimeSpan.FromMinutes(25);
+    public async Task RefreshCache()
+    {
+        var rate = await GetFeeRatesCore();
+        memoryCache.Set(cacheKey, rate, Expiration);
+    }
 
+    public bool CachedOnly { get; set; }
     internal async Task<BlockFeeRate[]> GetFeeRatesAsync()
     {
+        if (CachedOnly)
+            return memoryCache.Get(cacheKey) as BlockFeeRate[] ?? throw new InvalidOperationException("Fee rates unavailable");
         try
         {
             return  (await  memoryCache.GetOrCreateAsync(cacheKey, async entry =>
             {
-                entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(5);
+                entry.AbsoluteExpirationRelativeToNow = Expiration;
                 return await GetFeeRatesCore();
             }))!;
         }
@@ -73,8 +82,7 @@ internal record BlockFeeRate(int Blocks, FeeRate FeeRate);
     async Task<BlockFeeRate[]> GetFeeRatesCore()
     {
         var client = httpClientFactory.CreateClient(nameof(MempoolSpaceFeeProvider));
-        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));
-        using var result = await client.GetAsync(ExplorerLink, cts.Token);
+        using var result = await client.GetAsync(ExplorerLink);
         result.EnsureSuccessStatusCode();
         var recommendedFees = await result.Content.ReadAsAsync<Dictionary<string, decimal>>();
         var r = new List<BlockFeeRate>();