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This commit is contained in:
Jöran Malek 2023-11-27 01:14:18 +01:00
parent f79341e0c0
commit 3d635ad4c1
1 changed files with 20 additions and 15 deletions
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35
src/pdns-dhcp/Kea/KeaLeaseWatcher.cs
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@ -21,8 +21,10 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
Share = (FileShare)7,
};
private readonly Decoder _decoder;
private readonly FileSystemWatcher _fsw;
private readonly string _leaseFile;
private readonly Pipe _pipe;
private Channel<FileSystemEventArgs>? _eventChannel;
private Task? _executeTask;
private CancellationTokenSource? _stoppingCts;
@ -45,10 +47,12 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
throw new ArgumentException($"{nameof(options.Leases)} must point to a file in an existing path.", nameof(options));
}
_decoder = Encoding.UTF8.GetDecoder();
_leaseFile = leaseFile.ToString();
_fsw = new(leaseDirectory, _leaseFile);
_fsw.Changed += OnLeaseChanged;
_fsw.Error += OnLeaseError;
_pipe = new();
}
public Task StartAsync(CancellationToken cancellationToken)
@ -82,14 +86,15 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
private async Task Reading(CancellationToken stoppingToken)
{
SemaphoreSlim readerLock = new(1, 1);
while (!stoppingToken.IsCancellationRequested)
{
using CancellationTokenSource loopCts = CancellationTokenSource.CreateLinkedTokenSource(stoppingToken);
var loopToken = loopCts.Token;
_eventChannel = Channel.CreateUnbounded<FileSystemEventArgs>();
_fsw.EnableRaisingEvents = true;
Task reader = FileReader(loopToken);
using SemaphoreSlim waitTrap = new(0, 1);
using SemaphoreSlim changeEvent = new(0, 1);
Task reader = FileReader(waitTrap, changeEvent, loopToken);
try
{
await foreach (var @event in _eventChannel.Reader.ReadAllAsync(loopToken))
@ -108,12 +113,12 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
if (reader is not { IsCompleted: false })
{
reader = FileReader(loopToken);
reader = FileReader(waitTrap, changeEvent, loopToken);
}
if (@event.ChangeType == WatcherChangeTypes.Changed)
if (waitTrap.Wait(0, CancellationToken.None))
{
changeEvent.Release();
}
}
}
@ -133,11 +138,9 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
}
}
private async Task FileReader(CancellationToken stoppingToken)
private async Task FileReader(SemaphoreSlim waitTrap, SemaphoreSlim changeEvent, CancellationToken stoppingToken)
{
Pipe buffer = new();
var writer = buffer.Writer;
var textDecoder = Encoding.UTF8.GetDecoder();
PipeWriter writer = _pipe.Writer;
SepReader? reader = null;
try
{
@ -151,14 +154,14 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
{
if (reader is null)
{
reader = Sep.Reader().From(buffer.Reader.AsStream());
reader = Sep.Reader().From(_pipe.Reader.AsStream());
continue;
}
if (!reader.MoveNext())
{
// TODO Error state.
continue;
return;
}
}
@ -166,20 +169,22 @@ public abstract class KeaDhcpLeaseWatcher : IHostedService
int read = await file.ReadAsync(memory, stoppingToken);
if (read > 0)
{
CountNewLines(textDecoder, memory[..read], ref newLinesEncountered, ref awaitLineFeed);
CountNewLines(_decoder, memory[..read], ref newLinesEncountered, ref awaitLineFeed);
writer.Advance(read);
}
else
{
// TODO Await.
var acquireLock = changeEvent.WaitAsync(stoppingToken);
waitTrap.Release();
await acquireLock.ConfigureAwait(continueOnCapturedContext: false);
}
}
}
catch { }
finally
{
writer.Complete();
reader?.Dispose();
writer.Complete();
_pipe.Reset();
}
static void CountNewLines(Decoder decoder, in Memory<byte> memory, ref int newLinesEncountered, ref bool awaitLineFeed)