Limit the number of goroutines used for the update of ingress status

vendor/gopkg.in/go-playground/pool.v3/pool.go

@@ -0,0 +1,32 @@
+package pool
+
+// Pool contains all information for a pool instance.
+type Pool interface {
+
+	// Queue queues the work to be run, and starts processing immediately
+	Queue(fn WorkFunc) WorkUnit
+
+	// Reset reinitializes a pool that has been closed/cancelled back to a working
+	// state. if the pool has not been closed/cancelled, nothing happens as the pool
+	// is still in a valid running state
+	Reset()
+
+	// Cancel cancels any pending work still not committed to processing.
+	// Call Reset() to reinitialize the pool for use.
+	Cancel()
+
+	// Close cleans up pool data and cancels any pending work still not committed
+	// to processing. Call Reset() to reinitialize the pool for use.
+	Close()
+
+	// Batch creates a new Batch object for queueing Work Units separate from any
+	// others that may be running on the pool. Grouping these Work Units together
+	// allows for individual Cancellation of the Batch Work Units without affecting
+	// anything else running on the pool as well as outputting the results on a
+	// channel as they complete. NOTE: Batch is not reusable, once QueueComplete()
+	// has been called it's lifetime has been sealed to completing the Queued items.
+	Batch() Batch
+}
+
+// WorkFunc is the function type needed by the pool for execution
+type WorkFunc func(wu WorkUnit) (interface{}, error)