Forge.RetryPolicy (Forge v0.1.1)

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Retry policy configuration for stage execution.

Defines retry behavior including max attempts, backoff strategy, and which errors are retriable. Based on ADR-003.

Backoff Strategies

  • :jittered_exponential - Exponential backoff with ±25% jitter to avoid thundering herd
  • :fixed - Constant delay between retries
  • :linear - Linear increase in delay

Examples

# Default policy: 3 attempts with jittered exponential backoff
policy = Forge.RetryPolicy.new()

# Custom policy for LLM API calls
policy = Forge.RetryPolicy.new(
  max_attempts: 5,
  backoff: :jittered_exponential,
  base_delay_ms: 1000,
  max_delay_ms: 30_000,
  retriable_errors: [429, 500, 502, 503, 504]
)

# No retries for deterministic stages
policy = Forge.RetryPolicy.new(max_attempts: 1)

Summary

Types

backoff_strategy()
retriable_errors()
t()

Functions

compute_delay(attempt, policy)

Computes the delay in milliseconds for a given attempt.

default()

Returns the default retry policy as specified in ADR-003.

new(opts \\ [])

Creates a new retry policy with given options.

Types

backoff_strategy()

@type backoff_strategy() :: :jittered_exponential | :fixed | :linear

retriable_errors()

@type retriable_errors() :: :all | :none | [integer() | module() | atom()]

t()

@type t() :: %Forge.RetryPolicy{
  backoff: backoff_strategy(),
  base_delay_ms: pos_integer(),
  max_attempts: pos_integer(),
  max_delay_ms: pos_integer(),
  retriable_errors: retriable_errors()
}

Functions

compute_delay(attempt, policy)

Computes the delay in milliseconds for a given attempt.

Examples

iex> policy = Forge.RetryPolicy.new(backoff: :fixed, base_delay_ms: 500)
iex> Forge.RetryPolicy.compute_delay(1, policy)
500

iex> policy = Forge.RetryPolicy.new(backoff: :linear, base_delay_ms: 1000)
iex> Forge.RetryPolicy.compute_delay(2, policy)
2000

default()

Returns the default retry policy as specified in ADR-003.

new(opts \\ [])

Creates a new retry policy with given options.

Options

  • :max_attempts - Maximum number of attempts (default: 3)
  • :backoff - Backoff strategy (default: :jittered_exponential)
  • :base_delay_ms - Base delay in milliseconds (default: 1000)
  • :max_delay_ms - Maximum delay in milliseconds (default: 60_000)
  • :retriable_errors - Which errors to retry (default: :all)
    • :all - Retry all errors
    • :none - Don't retry any errors
    • List of HTTP status codes, exception modules, or error atoms