Durable.Executor.Backoff (Durable v0.1.0-rc)
View SourceBackoff strategies for step retry logic.
Supports three backoff strategies:
:exponential- Delay grows exponentially (2^attempt * base):linear- Delay grows linearly (attempt * base):constant- Fixed delay between retries
All delays are in milliseconds and capped at a configurable maximum.
Summary
Functions
Calculates the delay before the next retry attempt.
Calculates delay with jitter to avoid thundering herd.
Sleeps for the calculated backoff duration.
Types
@type opts() :: %{ optional(:base) => pos_integer(), optional(:max_backoff) => pos_integer() }
@type strategy() :: :exponential | :linear | :constant
Functions
@spec calculate(strategy(), pos_integer(), opts()) :: pos_integer()
Calculates the delay before the next retry attempt.
Arguments
strategy- The backoff strategy to useattempt- The current attempt number (1-based)opts- Options for the backoff calculation
Options
:base- Base delay in milliseconds (default: 1000):max_backoff- Maximum delay in milliseconds (default: 30000 = 30s). Kept low because the backoff blocks the worker in-process; raise it only if yourstale_lock_timeoutcomfortably exceeds the chosen ceiling.
Examples
iex> Backoff.calculate(:exponential, 1, %{base: 1000})
2000
iex> Backoff.calculate(:exponential, 3, %{base: 1000})
8000
iex> Backoff.calculate(:linear, 3, %{base: 1000})
3000
iex> Backoff.calculate(:constant, 5, %{base: 1000})
1000@spec calculate_with_jitter(strategy(), pos_integer(), opts()) :: non_neg_integer()
Calculates delay with jitter to avoid thundering herd.
Adds random jitter of ±25% to the calculated delay.
Examples
# Delay will be between 1500 and 2500 for exponential with attempt=1
Backoff.calculate_with_jitter(:exponential, 1, %{base: 1000})@spec sleep(strategy(), pos_integer(), opts()) :: :ok
Sleeps for the calculated backoff duration.
Examples
Backoff.sleep(:exponential, 2, %{base: 1000})