public ConditionalHealthCheck(Func <IHealthCheck> healthCheckFactory,
Func <HealthCheckContext, CancellationToken, Task <bool> > predicate,
ConditionalHealthCheckOptions?options,
ILogger <ConditionalHealthCheck>?logger)
{
HealthCheckFactory = healthCheckFactory ?? throw new ArgumentNullException(nameof(healthCheckFactory));
_predicate = predicate ?? throw new ArgumentNullException(nameof(predicate));
_options = ConditionalHealthCheckOptions.DefaultFrom(options);
_logger = logger;
}
/// <summary>
/// Enables an existing health check to be evaluated only when a specific condition occurs,
/// that is described by a type implementing <see cref="IConditionalHealthCheckPolicy"/>
/// and which will be executed on every health check request.
/// </summary>
/// <remarks>
/// The health check policy instance is provided by a function that receives as input <see cref="IServiceProvider"/>, <see cref="HealthCheckContext"/> and a <see cref="CancellationToken"/>
/// and it returns a <see cref="Task"/> representing the asynchronous operation that returns the health check policy instance.
/// </remarks>
/// <typeparam name="T">The type implementing <see cref="IConditionalHealthCheckPolicy"/>.</typeparam>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="name">
/// The name of the existing health check, ie. "Redis", "redis", "S3", "My Health Check".
/// The health check must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="policyProvider">The function that returns the instance based on which the health check execution is decided to run on not.</param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
/// <exception cref="InvalidOperationException">When the policy provider returns a null instance.</exception>
public static IHealthChecksBuilder CheckOnlyWhen <T>(this IHealthChecksBuilder builder,
string name,
Func <IServiceProvider, HealthCheckContext, CancellationToken, Task <T> > policyProvider,
ConditionalHealthCheckOptions?options = null)
where T : IConditionalHealthCheckPolicy
=> builder.CheckOnlyWhen(name, async(sp, context, token) =>
{
var policy = await policyProvider(sp, context, token);
if (policy == null)
{
throw new InvalidOperationException($"A policy of type `{typeof(T).Name}` could not be retrieved as it was null.");
}
return(await policy.Evaluate(context));
}, options);
/// <summary>
/// Enables multiple existing health checks to be evaluated only when a specific condition occurs,
/// that is described by an asynchronous predicate which will be executed on every health check request.
/// </summary>
/// <remarks>
/// The condition is expressed by a predicate which receives as input <see cref="IServiceProvider"/>, <see cref="HealthCheckContext"/> and a <see cref="CancellationToken"/>
/// and it returns a <see cref="Task"/> representing the asynchronous operation returning the predicate result.
/// </remarks>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="names">
/// The list of names of the existing health checks, ie. "Redis", "redis", "S3", "My Health Check".
/// The health checks must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="predicate"></param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen(this IHealthChecksBuilder builder,
string[] names,
Func <IServiceProvider, HealthCheckContext, CancellationToken, Task <bool> > predicate,
ConditionalHealthCheckOptions?options = null)
{
if (names == null || names.Length == 0)
{
throw new ArgumentException("The health checks names cannot be null or an empty array.", nameof(names));
}
foreach (var name in names)
{
builder.CheckOnlyWhen(name, predicate, options);
}
return(builder);
}
/// <summary>
/// Enables an existing health check to be evaluated only when a specific condition occurs,
/// that is described by an asynchronous predicate which will be executed on every health check request.
/// </summary>
/// <remarks>
/// The condition is expressed by a predicate which receives as input <see cref="IServiceProvider"/>, <see cref="HealthCheckContext"/> and a <see cref="CancellationToken"/>
/// and it returns a <see cref="Task"/> representing the asynchronous operation returning the predicate result.
/// </remarks>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="name">
/// The name of the existing health check, ie. "Redis", "redis", "S3", "My Health Check".
/// The health check must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="predicate">The predicate describing when to run the health check. If it returns true, then the health check is executed, otherwise is not.</param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen(this IHealthChecksBuilder builder,
string name,
Func <IServiceProvider, HealthCheckContext, CancellationToken, Task <bool> > predicate,
ConditionalHealthCheckOptions?options = null)
{
if (string.IsNullOrEmpty(name))
{
throw new ArgumentException("Health check registration name cannot be null or empty.", nameof(name));
}
if (predicate == null)
{
throw new ArgumentNullException(nameof(predicate));
}
builder.Services.Configure <HealthCheckServiceOptions>(healthCheckOptions =>
{
var registration = healthCheckOptions.Registrations.FirstOrDefault(c => string.Equals(c.Name, name, StringComparison.OrdinalIgnoreCase));
if (registration == null)
{
throw new InvalidOperationException($"A health check registration named `{name}` was not found in the health registrations list, " +
"so its conditional check cannot be configured. " +
$"The registration must be added before configuring the conditional predicate, so `{nameof(CheckOnlyWhen)}` must be called after the AddHealthCheck methods. " +
$"The exiting registrations are: \n" +
$"{string.Join("\n", healthCheckOptions.Registrations.Select(c => " `" + c.Name + "`"))}");
}
var factory = registration.Factory;
registration.Factory = sp => new ConditionalHealthCheck(
() => factory(sp),
(context, token) => predicate(sp, context, token),
options,
sp.GetService <ILogger <ConditionalHealthCheck> >()
);
});
return(builder);
}
internal static ConditionalHealthCheckOptions DefaultFrom(ConditionalHealthCheckOptions?options) => new ConditionalHealthCheckOptions
{
NotCheckedTagName = options?.NotCheckedTagName ?? DefaultNotCheckedTagName,
HealthStatusWhenNotChecked = options?.HealthStatusWhenNotChecked ?? DefaultHealthStatusWhenNotChecked
};
/// <summary>
/// Enables an existing health check to be evaluated only when a specific condition occurs,
/// that is described by a immediately evaluated condition.
/// </summary>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="name">
/// The name of the existing health check, ie. "Redis", "redis", "S3", "My Health Check".
/// The health check must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="conditionToRun">True if the health check should be evaluated, or false if not.</param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen(this IHealthChecksBuilder builder,
string name,
bool conditionToRun,
ConditionalHealthCheckOptions?options = null)
=> builder.CheckOnlyWhen(name, (_, __, ___) => Task.FromResult(conditionToRun), options);
/// <summary>
/// Enables an existing health check to be evaluated only when a specific condition occurs,
/// that is described by a type implementing <see cref="IConditionalHealthCheckPolicy"/>
/// and which type's instance will be executed on every health check request.
/// </summary>
/// <remarks>
/// The <see cref="IConditionalHealthCheckPolicy"/> instance is provided by a function via the <paramref name="policyProvider"/> parameter.
/// </remarks>
/// <typeparam name="T">The type implementing <see cref="IConditionalHealthCheckPolicy"/>.</typeparam>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="names">
/// The list of names of the existing health checks, ie. "Redis", "redis", "S3", "My Health Check".
/// The health checks must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="policyProvider">The function that returns the instance based on which the health check execution is decided to run on not.</param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen <T>(this IHealthChecksBuilder builder,
string[] names,
Func <T> policyProvider,
ConditionalHealthCheckOptions?options = null)
where T : IConditionalHealthCheckPolicy
=> builder.CheckOnlyWhen(names, (_, __, ___) => Task.FromResult(policyProvider()), options);
/// <summary>
/// Enables multiple existing health checks to be evaluated only when a specific condition occurs,
/// that is described by a type implementing <see cref="IConditionalHealthCheckPolicy"/>
/// and which will be executed on every health check request.
/// </summary>
/// <remarks>
/// The instance of this type is created with every request and its dependencies are resolved by <see cref="IServiceProvider"/>.
/// If the constructor has more arguments then these can be passed via the <paramref name="conditionalHealthCheckPolicyCtorArgs"/> parameter.
/// </remarks>
/// <typeparam name="T">The type implementing <see cref="IConditionalHealthCheckPolicy"/>.</typeparam>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="names">
/// The list of names of the existing health checks, ie. "Redis", "redis", "S3", "My Health Check".
/// The health checks must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="conditionalHealthCheckPolicyCtorArgs"></param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen <T>(this IHealthChecksBuilder builder,
string[] names,
ConditionalHealthCheckOptions?options = null,
params object[] conditionalHealthCheckPolicyCtorArgs)
where T : IConditionalHealthCheckPolicy
=> builder.CheckOnlyWhen(names, (sp, _, __) => Task.FromResult(ActivatorUtilities.CreateInstance <T>(sp, conditionalHealthCheckPolicyCtorArgs)), options);
/// <summary>
/// Enables multiple existing health checks to be evaluated only when a specific condition occurs,
/// that is described by predicate which will be executed on every health check request.
/// </summary>
/// <remarks>
/// The condition is expressed by a predicate that returns a boolean value based on which is decided the health check is executed or not.
/// </remarks>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="names">
/// The list of names of the existing health checks, ie. "Redis", "redis", "S3", "My Health Check".
/// The health checks must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="predicate">The predicate describing when to run the health check. If it returns true, then the health check is executed, otherwise is not. </param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen(this IHealthChecksBuilder builder,
string[] names,
Func <bool> predicate,
ConditionalHealthCheckOptions?options = null)
=> builder.CheckOnlyWhen(names, (_, __, ___) => Task.FromResult(predicate()), options);
/// <summary>
/// Enables an existing health check to be evaluated only when a specific condition occurs,
/// that is described by a type implementing <see cref="IConditionalHealthCheckPolicy"/>
/// and which given instance's method will be executed on every health check request.
/// </summary>
/// <remarks>
/// The <see cref="IConditionalHealthCheckPolicy"/> instance is provided as an argument of this method.
/// </remarks>
/// <typeparam name="T">The type implementing <see cref="IConditionalHealthCheckPolicy"/>.</typeparam>
/// <param name="builder">The builder used to register health checks.</param>
/// <param name="name">
/// The name of the existing health check, ie. "Redis", "redis", "S3", "My Health Check".
/// The health check must be previously registered using the other <see cref="IHealthChecksBuilder" /> extensions, like AddRedis, AddRabbitMQ, AddCheck, etc.
/// You can use the static <see cref="Registrations"/> class that contains a list of well-known names,
/// otherwise specify the name of the previously added health check.
/// </param>
/// <param name="policy">The conditional health check policy instance.</param>
/// <param name="options">A list of options to override the default behavior. See <see cref="ConditionalHealthCheckOptions"/> for extra details.</param>
/// <returns>The same builder used to register health checks.</returns>
/// <exception cref="ArgumentException">When the name of the health check is not provided, ie. is null or is an empty string.</exception>
/// <exception cref="InvalidOperationException">When the health check identified by the previously given name is not registered yet.</exception>
public static IHealthChecksBuilder CheckOnlyWhen <T>(this IHealthChecksBuilder builder,
string name,
T policy,
ConditionalHealthCheckOptions?options = null)
where T : IConditionalHealthCheckPolicy
=> builder.CheckOnlyWhen(name, (_, __, ___) => Task.FromResult(policy), options);