Module: Familia::Features::Expiration

Extended by:
ClassMethods
Defined in:
lib/familia/features/expiration.rb

Defined Under Namespace

Modules: ClassMethods

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/familia/features/expiration.rb', line 21

def self.included base
  Familia.ld "[#{base}] Loaded #{self}"
  base.extend ClassMethods

  # Optionally define ttl in the class to make
  # sure we always have an array to work with.
  unless base.instance_variable_defined?(:@ttl)
    base.instance_variable_set(:@ttl, @ttl) # set above
  end
end

Instance Method Details

#ttl ⇒ Object 



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# File 'lib/familia/features/expiration.rb', line 36

def ttl
  @ttl || self.class.ttl
end

#ttl=(v) ⇒ Object 



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# File 'lib/familia/features/expiration.rb', line 32

def ttl=(v)
  @ttl = v.to_f
end

#update_expiration(ttl = nil) ⇒ Boolean

Note:

If TTL is zero, your data gets a VIP pass to the Redis eternity club. Fancy, huh?

Yo, check it out! We’re gonna give our Redis data an expiration date!

It’s like slapping a “Best Before” sticker on your favorite snack, but for data. How cool is that?

Examples:

Teaching your pet rock the concept of mortality

rocky.update_expiration(86400) # Dwayne gets to party in Redis for one whole day!

Parameters:

  • ttl (Integer, nil) (defaults to: nil) —

    The Time To Live in seconds. Nil? No worries! We’ll dig up the default from our secret stash.

Returns:

  • (Boolean) —

    Did Redis pin that expiry note successfully? True for “Yep!”, false for “Oops, butter fingers!”

Raises:

  • (Familia::Problem) —

    If you try to feed it non-numbers or time-travel (negative numbers). It’s strict, but fair!



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# File 'lib/familia/features/expiration.rb', line 60

def update_expiration(ttl = nil)
  ttl ||= self.ttl
  # It's important to raise exceptions here and not just log warnings. We
  # don't want to silently fail at setting expirations and cause data
  # retention issues (e.g. not removed in a timely fashion).
  #
  # For the same reason, we don't want to default to 0 bc there's not a
  # good reason for the ttl to not be set in the first place. If the
  # class doesn't have a ttl, the default comes from Familia.ttl (which
  # is 0).
  unless ttl.is_a?(Numeric)
    raise Familia::Problem, "TTL must be a number (#{ttl.class} in #{self.class})"
  end

  if ttl.zero?
    return Familia.ld "[update_expiration] No expiration for #{self.class} (#{rediskey})"
  end

  Familia.ld "[update_expiration] Expires #{rediskey} in #{ttl} seconds"

  # Redis' EXPIRE command returns 1 if the timeout was set, 0 if key does
  # not exist or the timeout could not be set. Via redis-rb here, it's
  # a bool.
  expire(ttl)
end