Sha256: f02b05ea90818e553280799ee4ac46735db071c7d1d507f3d048c4a0aee2f03a
Contents?: true
Size: 1.97 KB
Versions: 16
Compression:
Stored size: 1.97 KB
Contents
module RedisFailover
# NodeWatcher periodically monitors a specific redis node for its availability.
# NodeWatcher instances periodically report a redis node's current state
# to the NodeManager for proper handling.
class NodeWatcher
include Util
# Time to sleep before checking on the monitored node's status.
WATCHER_SLEEP_TIME = 2
# Creates a new instance.
#
# @param [NodeManager] manager the node manager
# @param [Node] node the node to watch
# @param [Integer] max_failures the max failues before reporting node as down
def initialize(manager, node, max_failures)
@manager = manager
@node = node
@max_failures = max_failures
@monitor_thread = nil
@done = false
end
# Starts the node watcher.
#
# @note this method returns immediately and causes monitoring to be
# performed in a new background thread
def watch
@monitor_thread ||= Thread.new { monitor_node }
self
end
# Performs a graceful shutdown of this watcher.
def shutdown
@done = true
@node.wakeup
@monitor_thread.join if @monitor_thread
rescue
# best effort
end
private
# Periodically monitors the redis node and reports state changes to
# the {RedisFailover::NodeManager}.
def monitor_node
failures = 0
loop do
begin
return if @done
sleep(WATCHER_SLEEP_TIME)
@node.ping
failures = 0
if @node.syncing_with_master?
notify(:syncing)
else
notify(:available)
@node.wait
end
rescue NodeUnavailableError
failures += 1
if failures >= @max_failures
notify(:unavailable)
failures = 0
end
end
end
end
# Notifies the manager of a node's state.
#
# @param [Symbol] state the node's state
def notify(state)
@manager.notify_state(@node, state)
end
end
end
Version data entries
16 entries across 16 versions & 2 rubygems