Class ExponentialRetryPolicy

Implements an IRetryPolicy that retries an operation first at an initial interval and then doubles the interval up to a limit for a specified maximum number of times.

Inheritance
object
RetryPolicyBase
ExponentialRetryPolicy
Implements
Inherited Members
Namespace: Neon.Retry
Assembly: Neon.Common.dll
Syntax
public class ExponentialRetryPolicy : RetryPolicyBase, IRetryPolicy
Remarks

You can enable transient error logging by passing a non-empty logCategory name to the constructor. This creates an embedded ILogger using that name and any retried transient errors will then be logged as warnings including [transient-retry] in the message.

note

Only the retried errors will be logged. The final exception thrown after all retries fail will not be logged because it's assumed that these will be caught and handled upstack by application code.

Choose a category name that can be used to easily identify the affected component. For example, yugabyte:my-cluster to identify a specific YugaBYte database cluster.

Constructors

ExponentialRetryPolicy(Func<Exception, bool>, int, TimeSpan?, TimeSpan?, TimeSpan?, string)

Constructs the retry policy with a specific transitent detection function.

Declaration
public ExponentialRetryPolicy(Func<Exception, bool> transientDetector = null, int maxAttempts = -1, TimeSpan? initialRetryInterval = null, TimeSpan? maxRetryInterval = null, TimeSpan? timeout = null, string categoryName = "transient-errors")
Parameters
Type Name Description
Func<Exception, bool> transientDetector

Optionally specifies the function that determines whether an exception is transient (see TransientDetector). You can pass null when all exceptions are to be considered to be transient.
int maxAttempts

Optionally specifies the maximum number of times an action should be retried (defaults to 5).
TimeSpan? initialRetryInterval

Optionally specifies the initial retry interval between retry attempts (defaults to 1 second).
TimeSpan? maxRetryInterval

Optionally specifies the maximum retry interval (defaults to essentially unlimited: 24 hours).
TimeSpan? timeout

Optionally specifies the maximum time the operation will be retried (defaults to unconstrained)
string categoryName

Optionally customizes the transient error logging source category name (defaults to DefaultCategoryName). You can disable transient error logging by passing null or by adding an event handler to OnTransient that ignores the event and also indicates that the event was handled.
Remarks

The maxAttempts parameter defaults to -1 indicating that the operation should be attempted up to 5 times, unless a Timeout is specified. In this case, maxAttempts will be ignored and the timeout will be honored.

When maxAttempts is greater than or equal to zero and Timeout is passed, then both maxAttempts and Timeout will be honored, with retries stopping when either are exceeded.

ExponentialRetryPolicy(Type, int, TimeSpan?, TimeSpan?, TimeSpan?, string)

Constructs the retry policy to handle a specific exception type as transient.

Declaration
public ExponentialRetryPolicy(Type exceptionType, int maxAttempts = -1, TimeSpan? initialRetryInterval = null, TimeSpan? maxRetryInterval = null, TimeSpan? timeout = null, string categoryName = null)
Parameters
Type Name Description
Type exceptionType

Specifies the exception type to be considered to be transient.
int maxAttempts

Optionally specifies the maximum number of times an action should be retried (defaults to 5).
TimeSpan? initialRetryInterval

Optionally specifies the initial retry interval between retry attempts (defaults to 1 second).
TimeSpan? maxRetryInterval

Optionally specifies the maximum retry interval (defaults to essentially unlimited: 24 hours).
TimeSpan? timeout

Optionally specifies the maximum time the operation will be retried (defaults to unconstrained)
string categoryName

Optionally enables transient error logging by identifying the source category name (defaults to null).
Remarks

The maxAttempts parameter defaults to -1 indicating that the operation should be attempted up to 5 times, unless a Timeout is specified. In this case, maxAttempts will be ignored and the timeout will be honored.

When maxAttempts is greater than or equal to zero and Timeout is passed, then both maxAttempts and Timeout will be honored, with retries stopping when either are exceeded.

ExponentialRetryPolicy(Type[], int, TimeSpan?, TimeSpan?, TimeSpan?, string)

Constructs the retry policy to handle a multiple exception types as transient.

Declaration
public ExponentialRetryPolicy(Type[] exceptionTypes, int maxAttempts = -1, TimeSpan? initialRetryInterval = null, TimeSpan? maxRetryInterval = null, TimeSpan? timeout = null, string categoryName = null)
Parameters
Type Name Description
Type[] exceptionTypes

Specifies the exception type to be considered to be transient.
int maxAttempts

Optionally specifies the maximum number of times an action should be retried (defaults to 5).
TimeSpan? initialRetryInterval

Optionally specifies the initial retry interval between retry attempts (defaults to 1 second).
TimeSpan? maxRetryInterval

Optionally specifies the maximum retry interval (defaults to essentially unlimited: 24 hours).
TimeSpan? timeout

Optionally specifies the maximum time the operation will be retried (defaults to unconstrained)
string categoryName

Optionally enables transient error logging by identifying the source category name (defaults to null).
Remarks

The maxAttempts parameter defaults to -1 indicating that the operation should be attempted up to 5 times, unless a Timeout is specified. In this case, maxAttempts will be ignored and the timeout will be honored.

When maxAttempts is greater than or equal to zero and Timeout is passed, then both maxAttempts and Timeout will be honored, with retries stopping when either are exceeded.

Properties

InitialRetryInterval

Returns the initial interval between action retry attempts.

Declaration
public TimeSpan InitialRetryInterval { get; }
Property Value
Type Description
TimeSpan

MaxAttempts

Returns the maximum number of times the action should be attempted.

Declaration
public int MaxAttempts { get; }
Property Value
Type Description
int

MaxRetryInterval

Returns the maximum intervaL between action retry attempts.

Declaration
public TimeSpan MaxRetryInterval { get; }
Property Value
Type Description
TimeSpan

Methods

Clone(Func<Exception, bool>)

Returns a copy of the retry policy.

Declaration
public override IRetryPolicy Clone(Func<Exception, bool> transientDetector = null)
Parameters
Type Name Description
Func<Exception, bool> transientDetector

Optionally specifies a replacement transient detector function that will be set in the cloned policy.
Returns
Type Description
IRetryPolicy

The policy copy.
Overrides

Invoke(Action, CancellationToken)

Retries a synchronous action that returns no result when it throws exceptions due to transient errors. The classification of what is a transient error, the interval between the retries as well as the number of times the operation are retried are determined by the policy implementation.

Declaration
public override void Invoke(Action action, CancellationToken cancellationToken = default)
Parameters
Type Name Description
Action action

The synchronous action to be performed.
CancellationToken cancellationToken

Optionally specifies a cancellation token.
Overrides

InvokeAsync(Func<Task>, CancellationToken)

Retries an asynchronous action that returns no result when it throws exceptions due to transient errors. The classification of what is a transient error, the interval between the retries as well as the number of times the operation are retried are determined by the policy implementation.

Declaration
public override Task InvokeAsync(Func<Task> action, CancellationToken cancellationToken = default)
Parameters
Type Name Description
Func<Task> action

The asynchronous action to be performed.
CancellationToken cancellationToken

Optionally specifies a cancellation token.
Returns
Type Description
Task
Overrides

InvokeAsync<TResult>(Func<Task<TResult>>, CancellationToken)

Retries an asynchronous action that returns TResult when it throws exceptions due to transient errors. he classification of what is a transient error, the interval between the retries as well as the number of times the operation are retried are determined by the policy implementation.

Declaration
public override Task<TResult> InvokeAsync<TResult>(Func<Task<TResult>> action, CancellationToken cancellationToken = default)
Parameters
Type Name Description
Func<Task<TResult>> action

The asynchronous action to be performed.
CancellationToken cancellationToken

Optionally specifies a cancellation token.
Returns
Type Description
Task<TResult>

The action result.
Type Parameters
Name Description
TResult

The action result type.
Overrides

Invoke<TResult>(Func<TResult>, CancellationToken)

Retries a synchronous action that returns a result when it throws exceptions due to transient errors. The classification of what is a transient error, the interval between the retries as well as the number of times the operation are retried are determined by the policy implementation.

Declaration
public override TResult Invoke<TResult>(Func<TResult> action, CancellationToken cancellationToken = default)
Parameters
Type Name Description
Func<TResult> action

The synchronous action to be performed.
CancellationToken cancellationToken

Optionally specifies a cancellation token.
Returns
Type Description
TResult

The action result.
Type Parameters
Name Description
TResult

The action result type.
Overrides

Implements