优化域名解析

This commit is contained in:
陈国伟 2021-08-19 10:32:18 +08:00
parent 4499c640f5
commit 945fb993f5

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@ -25,7 +25,8 @@ namespace FastGithub.DomainResolve
private readonly TimeSpan lookupTimeout = TimeSpan.FromSeconds(2d); private readonly TimeSpan lookupTimeout = TimeSpan.FromSeconds(2d);
private readonly TimeSpan connectTimeout = TimeSpan.FromSeconds(2d); private readonly TimeSpan connectTimeout = TimeSpan.FromSeconds(2d);
private readonly TimeSpan resolveCacheTimeSpan = TimeSpan.FromMinutes(2d); private readonly TimeSpan pureResolveCacheTimeSpan = TimeSpan.FromMinutes(5d);
private readonly TimeSpan fastResolveCacheTimeSpan = TimeSpan.FromMinutes(1d);
private readonly ConcurrentDictionary<DnsEndPoint, SemaphoreSlim> semaphoreSlims = new(); private readonly ConcurrentDictionary<DnsEndPoint, SemaphoreSlim> semaphoreSlims = new();
/// <summary> /// <summary>
@ -56,12 +57,7 @@ namespace FastGithub.DomainResolve
try try
{ {
await semaphore.WaitAsync(cancellationToken); await semaphore.WaitAsync(cancellationToken);
if (this.memoryCache.TryGetValue<IPAddress>(endPoint, out var address) == false) return await this.LookupAsync(endPoint, cancellationToken);
{
address = await this.LookupAsync(endPoint, cancellationToken);
this.memoryCache.Set(endPoint, address, this.resolveCacheTimeSpan);
}
return address;
} }
finally finally
{ {
@ -77,20 +73,28 @@ namespace FastGithub.DomainResolve
/// <returns></returns> /// <returns></returns>
private async Task<IPAddress> LookupAsync(DnsEndPoint endPoint, CancellationToken cancellationToken) private async Task<IPAddress> LookupAsync(DnsEndPoint endPoint, CancellationToken cancellationToken)
{ {
var dnsEndPoints = new[] { this.fastGithubConfig.PureDns, this.fastGithubConfig.FastDns }; if (this.memoryCache.TryGetValue<IPAddress>(endPoint, out var address))
foreach (var dns in dnsEndPoints)
{ {
var addresses = await this.LookupCoreAsync(dns, endPoint, cancellationToken); return address;
var fastAddress = await this.GetFastIPAddressAsync(addresses, endPoint.Port, cancellationToken);
if (fastAddress != null)
{
this.logger.LogInformation($"[{endPoint.Host}->{fastAddress}]");
return fastAddress;
}
} }
throw new FastGithubException($"当前解析不到{endPoint.Host}可用的ip请刷新重试"); var expiration = this.pureResolveCacheTimeSpan;
address = await this.LookupCoreAsync(this.fastGithubConfig.PureDns, endPoint, cancellationToken);
if (address == null)
{
expiration = this.fastResolveCacheTimeSpan;
address = await this.LookupCoreAsync(this.fastGithubConfig.FastDns, endPoint, cancellationToken);
}
if (address == null)
{
throw new FastGithubException($"当前解析不到{endPoint.Host}可用的ip请刷新重试");
}
this.logger.LogInformation($"[{endPoint.Host}->{address}]");
this.memoryCache.Set(endPoint, address, expiration);
return address;
} }
/// <summary> /// <summary>
@ -100,19 +104,20 @@ namespace FastGithub.DomainResolve
/// <param name="endPoint"></param> /// <param name="endPoint"></param>
/// <param name="cancellationToken"></param> /// <param name="cancellationToken"></param>
/// <returns></returns> /// <returns></returns>
private async Task<IEnumerable<IPAddress>> LookupCoreAsync(IPEndPoint dns, DnsEndPoint endPoint, CancellationToken cancellationToken) private async Task<IPAddress?> LookupCoreAsync(IPEndPoint dns, DnsEndPoint endPoint, CancellationToken cancellationToken)
{ {
try try
{ {
var dnsClient = new DnsClient(dns); var dnsClient = new DnsClient(dns);
using var timeoutTokenSource = new CancellationTokenSource(this.lookupTimeout); using var timeoutTokenSource = new CancellationTokenSource(this.lookupTimeout);
using var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, timeoutTokenSource.Token); using var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, timeoutTokenSource.Token);
return await dnsClient.Lookup(endPoint.Host, RecordType.A, linkedTokenSource.Token); var addresses = await dnsClient.Lookup(endPoint.Host, RecordType.A, linkedTokenSource.Token);
return await this.FindFastValueAsync(addresses, endPoint.Port, cancellationToken);
} }
catch catch (Exception ex)
{ {
this.logger.LogWarning($"dns({dns})无法解析{endPoint.Host}"); this.logger.LogWarning($"dns({dns})无法解析{endPoint.Host}{ex.Message}");
return Enumerable.Empty<IPAddress>(); return default;
} }
} }
@ -123,7 +128,7 @@ namespace FastGithub.DomainResolve
/// <param name="port"></param> /// <param name="port"></param>
/// <param name="cancellationToken"></param> /// <param name="cancellationToken"></param>
/// <returns></returns> /// <returns></returns>
private async Task<IPAddress?> GetFastIPAddressAsync(IEnumerable<IPAddress> addresses, int port, CancellationToken cancellationToken) private async Task<IPAddress?> FindFastValueAsync(IEnumerable<IPAddress> addresses, int port, CancellationToken cancellationToken)
{ {
if (addresses.Any() == false) if (addresses.Any() == false)
{ {