Net6Configuration & Options 源码分析 Part3 IOptionsMonitor 是如何接收到配置文件变更并同步数据源的

1
2
3
4
5
6
7
8
9
10
var configuration = new ConfigurationBuilder().AddJsonFile(path: "profile.json",
optional: false,
reloadOnChange: true).Build();
new ServiceCollection().AddOptions().Configure(configuration).BuildServiceProvider().GetRequiredService>().OnChange(profile => Console.WriteLine($"data reload: {profile.Age}"));
Console.Read();
public class Profile
{
public int Age { get; set; }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
public abstract class FileConfigurationProvider : ConfigurationProvider, IDisposable
{
public FileConfigurationProvider(FileConfigurationSource source!!)
{
Source = source;
if (Source.ReloadOnChange && Source.FileProvider != null)
{
_changeTokenRegistration = ChangeToken.OnChange(
() => Source.FileProvider.Watch(Source.Path!),
() =>
{
// 重新从JsonFile Load 数据并
Load(reload: true);
});
}
}
private void Load(bool reload)
{
IFileInfo? file = Source.FileProvider?.GetFileInfo(Source.Path ?? string.Empty);
using Stream stream = OpenRead(file);
try
{
// 此处调用具体实现类的Load 方法例如JsonConfigurationProvider
Load(stream);
}
// 发送OnReload 并重新生成ConfigurationReloadToken共下次使用。
OnReload();
}
}
public class JsonConfigurationProvider : FileConfigurationProvider
{
public JsonConfigurationProvider(JsonConfigurationSource source) : base(source) { }
public override void Load(Stream stream)
{
Data = JsonConfigurationFileParser.Parse(stream);
}
}
public abstract class ConfigurationProvider : IConfigurationProvider
{
protected void OnReload()
{
ConfigurationReloadToken previousToken = Interlocked.Exchange(ref _reloadToken, new ConfigurationReloadToken());
previousToken.OnReload();
}
public IChangeToken GetReloadToken()
{
return _reloadToken;
}
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
// ConfigurationRoot向IConfigurationProvider注册回调函数拼接回调链条。
public class ConfigurationRoot : IConfigurationRoot, IDisposable
{
_providers = providers;
_changeTokenRegistrations = new List(providers.Count);
foreach (IConfigurationProvider p in providers)
{
p.Load();
// 回调链条拼接
_changeTokenRegistrations.Add(ChangeToken.OnChange(() => p.GetReloadToken(), () => RaiseChanged()));
}
private void RaiseChanged()
{
ConfigurationReloadToken previousToken = Interlocked.Exchange(ref _changeToken, new ConfigurationReloadToken());
previousToken.OnReload();
}
}
// ConfigurationChangeTokenSource 包装类与注册 OptionsConfigurationServiceCollectionExtensions
public class ConfigurationChangeTokenSource<TOptions> : IOptionsChangeTokenSource<TOptions>
{
private IConfiguration _config;
public ConfigurationChangeTokenSource(IConfiguration config) : this(Options.DefaultName, config){}
public IChangeToken GetChangeToken()
{
return _config.GetReloadToken();
}
}
public static class OptionsConfigurationServiceCollectionExtensions
{
public static IServiceCollection Configure<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TOptions>(this IServiceCollection services!!, string? name, IConfiguration config!!, Action? configureBinder) where TOptions : class
{
services.AddOptions();
services.AddSingleton>(new ConfigurationChangeTokenSource(name, config));
return services.AddSingleton>(new NamedConfigureFromConfigurationOptions(name, config, configureBinder));
}
}
public class OptionsMonitor<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] TOptions> : IOptionsMonitor<TOptions>, IDisposable
where TOptions : class
{
internal event Actionstring>? _onChange;
public OptionsMonitor(IOptionsFactory factory, IEnumerable> sources, IOptionsMonitorCache cache)
{
ChangeToken.OnChange(
() => source.GetChangeToken(),
(name) => InvokeChanged(name),
source.Name);
private void InvokeChanged(string? name)
{
name = name ?? Options.DefaultName;
_cache.TryRemove(name);
TOptions options = Get(name);
if (_onChange != null)
{
_onChange.Invoke(options, name);
}
}
}
public IDisposable OnChange(Actionstring> listener)
{
var disposable = new ChangeTrackerDisposable(this, listener);
_onChange += disposable.OnChange;
return disposable;
}
}

1
2
3
ConfigurationReloadToken previousToken = Interlocked.Exchange(ref _changeToken, new ConfigurationReloadToken());
previousToken.OnReload();