ickers/Extensions.Configuration.EntityFrameworkCore
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Improve exception/error handling

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This commit is contained in:
Rhys Ickeringill
2026-01-07 10:53:40 +11:00
parent 8acbab1832
commit db64055acb
4 changed files with 120 additions and 82 deletions
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88
RAIC.Extensions.Configuration.EntityFrameworkCore.PostgreSQL/PostgreSQLNotificationConfigurationReloader.cs
View File

@@ -52,22 +52,29 @@ internal class PostgreSQLNotificationConfigurationReloader : Microsoft.Extension
{
var dbConnection = Initialise();
do
try
{
await ListenForNotifications(stoppingToken);
try
do
{
await dbConnection.WaitAsync(stoppingToken);
try
{
await dbConnection.WaitAsync(stoppingToken);
}
catch (Exception e) when (e is not OperationCanceledException)
{
_logger?.LogWarning(e, "Exception while waiting for notifications on channel '{channel}'", _options.ChannelName);
}
}
catch (Exception e) when (e is not TaskCanceledException)
{
_logger?.LogWarning(e, "Exception while waiting for notifications on channel '{channel}'", _options.ChannelName);
}
}
while (ConnectionState.Open == dbConnection.State || await IsReconnectionPossible(stoppingToken));
while (ConnectionState.Open == dbConnection.State || await TryReconnect(stoppingToken));
_logger?.LogWarning("Giving up listening for notifications on channel '{channel}' because reconnection attempts exhausted. Configuration updates from database will no longer occur", _options.ChannelName);
_logger?.LogWarning("Giving up listening for notifications on channel '{channel}' because reconnection attempts exhausted. Configuration updates from database will no longer occur", _options.ChannelName);
}
catch (OperationCanceledException e)
{
_logger?.LogInformation(e, "Exiting due to signal from stopping token");
}
}
private Npgsql.NpgsqlConnection Initialise()
@@ -76,8 +83,37 @@ internal class PostgreSQLNotificationConfigurationReloader : Microsoft.Extension
dbConnection.Notification += OnNotification;
return dbConnection;
void OnNotification(object sender, Npgsql.NpgsqlNotificationEventArgs args)
{
_logger?.LogTrace("Received notification '{payload}' on channel '{channel}'", args.Payload, args.Channel);
if (args.Channel != _options.ChannelName)
return;
using (var previousCts = Interlocked.Exchange(ref _cts, new()))
{
previousCts.Cancel();
}
ReadOnlySpan<string> keyValue = args.Payload.Split('=', 2); // DEBT: Do split without heap allocation
switch (keyValue.Length)
{
case 2:
_configProvider.Set(keyValue[0], keyValue[1]);
break;
case 1:
_configProvider.Remove(keyValue[0]);
break;
default:
_logger?.LogWarning("Invalid '{channel}' payload '{payload}'", args.Channel, args.Payload);
return; // Don't proceed to debounced reload
}
_ = DebouncedProviderReload(); // Intentionally running without awaiting, may be cancelled
}
}
private async Task ListenForNotifications(CancellationToken stoppingToken)
{
var listenStatement = $"LISTEN {_options.ChannelName}";
@@ -86,40 +122,12 @@ internal class PostgreSQLNotificationConfigurationReloader : Microsoft.Extension
_logger?.LogInformation("Listening for notifications on channel '{channel}'", _options.ChannelName);
}
private void OnNotification(object sender, Npgsql.NpgsqlNotificationEventArgs args)
{
_logger?.LogTrace("Received notification '{payload}' on channel '{channel}'", args.Payload, args.Channel);
if (args.Channel != _options.ChannelName)
return;
using (var previousCts = Interlocked.Exchange(ref _cts, new()))
{
previousCts.Cancel();
}
ReadOnlySpan<string> keyValue = args.Payload.Split('=', 2); // DEBT: Do split without heap allocation
switch (keyValue.Length)
{
case 2:
_configProvider.Set(keyValue[0], keyValue[1]);
break;
case 1:
_configProvider.Remove(keyValue[0]);
break;
default:
_logger?.LogWarning("Invalid '{channel}' payload '{payload}'", args.Channel, args.Payload);
return; // Don't proceed to debounced reload
}
var _ = DebouncedProviderReload(); // Intentionally running without awaiting, may be cancelled
}
/// <summary>
/// Trigger reload of the <see cref="IEntityFrameworkCoreDbSetConfigurationProvider"/> after waiting for a [cancelable] debounce period
/// </summary>
/// <remarks>Does not log <see cref="TaskCanceledException "/> each time debounce task is cancelled, unlike <see cref="SimpleDebouncedProviderReload"/></remarks>
private async ValueTask DebouncedProviderReload()
private async Task DebouncedProviderReload()
{
var delayTask = Task.Delay(_options.DebounceInterval);
var cancelableTask = Task.Delay(Timeout.Infinite, _cts.Token);
@@ -154,7 +162,7 @@ internal class PostgreSQLNotificationConfigurationReloader : Microsoft.Extension
}
private async Task<bool> IsReconnectionPossible(CancellationToken stoppingToken)
private async Task<bool> TryReconnect(CancellationToken stoppingToken)
{
await Task.Delay(_options.InitialReconnectionDelay, stoppingToken);

10
RAIC.Extensions.Configuration.EntityFrameworkCore.PostgreSQL/README.md
View File

@@ -5,8 +5,8 @@ This library enhances `RAIC.Extensions.Configuration.EntityFrameworkCore` with s
## Goals
1. No polling!
1. Updates happen in background via worker service (`IHostedService`)
1. Only update settings which change rather than reloading all of them
1. Updates happen in background via a [hosted service](https://learn.microsoft.com/en-us/aspnet/core/fundamentals/host/hosted-services) implementation.
1. Only update settings which change rather than updating them all
## Requirements
* .NET 8
@@ -14,8 +14,8 @@ This library enhances `RAIC.Extensions.Configuration.EntityFrameworkCore` with s
## Gotchas
* Setting values cannot be `null` (as signified by the `RequiredAttribute` on `ISetting.Value`)
* Setting keys must not contain the `=` character (similar to `CommandLineConfigurationProvider` & `EnvironmentVariablesConfigurationProvider`)
* Small window of opportunity for updates to be missed during reconnection process
* Consider adding `Keepalive` to your conenction string (https://www.npgsql.org/doc/keepalive.html) if its not already present
* Small window of opportunity for updates to be missed during reconnection process after any network dropouts or other connectivity flakiness
* Consider adding `Keepalive` [parameter](https://www.npgsql.org/doc/keepalive.html) to your connection string if its not already present
## Known Issues
* Not tested under load
@@ -65,7 +65,7 @@ AFTER DELETE ON settings
FOR EACH ROW EXECUTE FUNCTION notify_setting_remove();
```
Reccommend adding your SQL to the migration which adds the `Settings` table/view (or a new migration if that table/view already exists).
Recommend adding your SQL to the migration which adds the `Settings` table/view (or a new migration if that table/view already exists).
## Usage Example