Class: Flare::BackoffPolicy

Inherits:
Object
  • Object
show all
Defined in:
lib/flare/backoff_policy.rb

Overview

Exponential backoff with jitter for retry logic. Based on Flipper’s implementation.

Constant Summary collapse

MIN_TIMEOUT_MS =

Default minimum timeout between intervals in milliseconds

1_000
MAX_TIMEOUT_MS =

Default maximum timeout between intervals in milliseconds

30_000
MULTIPLIER =

Value to multiply the current interval with for each retry attempt

1.5
RANDOMIZATION_FACTOR =

Randomization factor to create a range around the retry interval

0.5

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options = {}) ⇒ BackoffPolicy

Returns a new instance of BackoffPolicy.



22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
 
# File 'lib/flare/backoff_policy.rb', line 22

def initialize(options = {})
  @min_timeout_ms = options.fetch(:min_timeout_ms) {
    ENV.fetch("FLARE_BACKOFF_MIN_TIMEOUT_MS", MIN_TIMEOUT_MS).to_i
  }
  @max_timeout_ms = options.fetch(:max_timeout_ms) {
    ENV.fetch("FLARE_BACKOFF_MAX_TIMEOUT_MS", MAX_TIMEOUT_MS).to_i
  }
  @multiplier = options.fetch(:multiplier) {
    ENV.fetch("FLARE_BACKOFF_MULTIPLIER", MULTIPLIER).to_f
  }
  @randomization_factor = options.fetch(:randomization_factor) {
    ENV.fetch("FLARE_BACKOFF_RANDOMIZATION_FACTOR", RANDOMIZATION_FACTOR).to_f
  }

  validate!
  @attempts = 0
end

Instance Attribute Details

#attempts ⇒ Object (readonly)

Returns the value of attribute attempts.



20
21
22
 
# File 'lib/flare/backoff_policy.rb', line 20

def attempts
  @attempts
end

#max_timeout_ms ⇒ Object (readonly)

Returns the value of attribute max_timeout_ms.



19
20
21
 
# File 'lib/flare/backoff_policy.rb', line 19

def max_timeout_ms
  @max_timeout_ms
end

#min_timeout_ms ⇒ Object (readonly)

Returns the value of attribute min_timeout_ms.



19
20
21
 
# File 'lib/flare/backoff_policy.rb', line 19

def min_timeout_ms
  @min_timeout_ms
end

#multiplier ⇒ Object (readonly)

Returns the value of attribute multiplier.



19
20
21
 
# File 'lib/flare/backoff_policy.rb', line 19

def multiplier
  @multiplier
end

#randomization_factor ⇒ Object (readonly)

Returns the value of attribute randomization_factor.



19
20
21
 
# File 'lib/flare/backoff_policy.rb', line 19

def randomization_factor
  @randomization_factor
end

Instance Method Details

#next_interval ⇒ Object

Returns the next backoff interval in milliseconds.



41
42
43
44
45
46
47
48
49
50
51
 
# File 'lib/flare/backoff_policy.rb', line 41

def next_interval
  interval = @min_timeout_ms * (@multiplier**@attempts)
  interval = add_jitter(interval, @randomization_factor)

  @attempts += 1

  # Cap the interval to the max timeout
  result = [interval, @max_timeout_ms].min
  # Add small jitter even when maxed out
  result == @max_timeout_ms ? add_jitter(result, 0.05) : result
end

#reset ⇒ Object 



53
54
55
 
# File 'lib/flare/backoff_policy.rb', line 53

def reset
  @attempts = 0
end