Publish message on specific partition

[ChrisKujawa]

Adds a new feature to publish a message with a printable correlation key to an specific (given) partition. This is useful if we want to experiment with message correlation, for example disconnect certain partitions etc.

// The message publish partition distribution is based
// on the following hashcode and modulo by the partition count
//
// Since this calculation is used not only on publish, but also for
// opening the message and instance subscriptions we must support for
// backwards compatibility, otherwise message will not be correlated
//
// This allows us to make certain assumptions, and shortcuts.
//
// static int getSubscriptionHashCode(final DirectBuffer correlationKey) {
//   is equal to java.lang.String#hashCode
//   int hashCode = 0;
//
//   for (int i = 0, length = correlationKey.capacity(); i < length; i++) {
//      	hashCode = 31 * hashCode + correlationKey.getByte(i);
//   }
//   return hashCode;
// }
//
// and
//   public static int getSubscriptionPartitionId(
//      final DirectBuffer correlationKey, final int partitionCount) {
//    final int hashCode = getSubscriptionHashCode(correlationKey);
//    // partition ids range from START_PARTITION_ID .. START_PARTITION_ID + partitionCount
//    return Math.abs(hashCode % partitionCount) + START_PARTITION_ID;
//  }
// Based on the hash code function, we now that if the string has a length of one byte
// no multiplication will happen.
//
// Since we need a printable (for variables) character we start with ASCII code 48, until 126.
// Formulas:
//
// expectedPartition = (hashcode mod partitionCount) + partitionStartId
// hashcode = i ( 48 >= i >= 126) == ASCII CODE
//

Usage

$ ./zbchaos publish -v --partitionId 1
Connecting to zell-chaos
Successfully created port forwarding tunnel
Send message 'msg', with correaltion key '0' (ASCII: 48) 
Message was sent and returned key 2251799813685346, which corresponds to partition: 1

[npepinpe]

👍

Just one comment about verbose logging

[npepinpe]

👍 Very nice. I'm wondering if it shouldn't always be printed regardless, as if a test were to fail due to a partition mismatch, it would be pretty important info