Documentation
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Overview ¶
Package retry provides exponential backoff retry strategies for message delivery. It implements configurable retry logic with Dead Letter Queue threshold for permanent failures.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Strategy ¶
type Strategy struct {
MaxAttempts int // Maximum retry attempts before giving up
BaseDelay time.Duration // Initial retry delay (first attempt)
MaxDelay time.Duration // Maximum retry delay cap
ExponentialBase float64 // Backoff multiplier (e.g., 2.0 for doubling)
DLQThreshold int // Move to Dead Letter Queue after this many attempts
}
Strategy defines the retry behavior configuration for failed message deliveries. It implements exponential backoff with configurable parameters.
The retry schedule follows: delay = min(BaseDelay * ExponentialBase^attempt, MaxDelay)
Example with defaults (30s base, 2.0 exponential, 30m max):
Attempt 1: 30s Attempt 2: 1m Attempt 3: 2m Attempt 4: 4m Attempt 5: 8m (→ DLQ)
func DefaultStrategy ¶
func DefaultStrategy() Strategy
DefaultStrategy returns the production-ready default retry strategy. Configuration: 10 max attempts, 30s→30m exponential backoff, DLQ after 5 attempts.
This strategy has been battle-tested in the FreiCON Railway Management System.
func (Strategy) CalculateRetryDelay ¶
CalculateRetryDelay calculates the retry delay for a given attempt using exponential backoff. Formula: delay = min(BaseDelay * ExponentialBase^attemptNumber, MaxDelay)
Parameters:
- attemptNumber: The attempt number (0-based or 1-based depending on usage)
Returns the delay duration to wait before the next retry attempt.
func (Strategy) GetRetrySchedule ¶
GetRetrySchedule returns a human-readable description of the retry schedule. Useful for debugging, documentation, and displaying retry behavior to users.
Example output:
Retry Schedule: Attempt 1: after 30s Attempt 2: after 1m ... Attempt 5: after 8m → Move to DLQ
func (Strategy) IsRetryable ¶
IsRetryable checks if another retry attempt is allowed. Returns true if the attempt count is below the maximum attempts limit.
func (Strategy) ShouldMoveToDLQ ¶
ShouldMoveToDLQ determines if a message should be moved to the Dead Letter Queue. Returns true when the attempt count reaches or exceeds the DLQ threshold.
Source Files