RetryableTask

RetryableTask includes a single global function called withRetryableTask which executes a given operation with retries. Retries are determined by a given RetryPolicy.

The following example will execute a consumeCoffee-function until it succeeds, with a relay of 100ms, and a maximum of 3 attempts. ☕️

withRetryableTask(policy: DelayedRetryPolicy(delay: 100_000_000, maxRetries: 2)) {
    try consumeCoffee()
}

Installation

Using Swift Package Manager:

…
dependencies: [
    .package(url: "https://github.com/rosecoder/retryable-task.git", from: "1.0.0"),
],
…
targets: [
    .target(name: "YourProduct", dependencies: [
        .product(name: "RetryableTask", package: "retryable-task")
    ]),
]

Examples

Setting default policy

A default policy can be set by setting the static DefaultRetryPolicy.retryPolicy property. For example:

DefaultRetryPolicy.retryPolicy = DelayedRetryPolicy(delay: 100_000_000, maxRetries: 2)

This will use the new default retry policy for all calls to withRetryableTask which does not define a policy.

Using ImmediateRetryPolicy

ImmediateRetryPolicy is a retry policy with a immediate (no delay) before each retry.

Example:

DefaultRetryPolicy.retryPolicy = ImmediateRetryPolicy(
    maxRetries: 5
)

This will execute operations a maximum of 6 times with no delay between each execution.

Using DelayedRetryPolicy

DelayedRetryPolicy is a retry policy with a static delay before each retry.

Example:

DefaultRetryPolicy.retryPolicy = DelayedRetryPolicy(
    delay: 100_000_000,
    maxRetries: 5
)

This will execute operations a maximum of 6 times with a delay of 100ms between each execution.

Using ExponentialBackoffDelayRetryPolicy

ExponentialBackoffDelayRetryPolicy is a retry policy with a exponential increasing delay before each retry.

Example:

DefaultRetryPolicy.retryPolicy = ExponentialBackoffDelayRetryPolicy(
    minimumBackoffDelay: 100_000_000,
    maximumBackoffDelay: 400_000_000,
    maxRetries: 4
)

This will execute operations a maximum of 5 times with the following delays:

• 1th retry: 100ms
• 2nd retry: 200ms
• 3rd retry: 400ms
• 4th retry: 400ms

Using NoRetryPolicy

NoRetryPolicy is a retry policy with no retries at all. This can be usefull for unit tests where retries should not be made.

For example, this can be set up in a XCTestCase:

class MyTests: XCTestCase {

    override func setUp() {
        super.setUp()

        DefaultRetryPolicy.retryPolicy = NoRetryPolicy()
    }
}