Merge pull request #120 from mjayprateek/alpha_features_readme

Updating README with alpha features

README.md

@@ -234,6 +234,39 @@ All Ziggurat configs should be in your `clonfig` `config.edn` under the `:ziggur
 * jobs - The number of consumers that should be reading from the retry queues and the prefetch count of each consumer
 * http-server - Ziggurat starts an http server by default and gives apis for ping health-check and deadset management. This defines the port and the number of threads of the http server.
 
+## Alpha (Experimental) Features
+Ziggurat 2.12.6 introduces a few configurations to enable the following:
+- Add a delay (configurable) in processing the messages from RabbitMQ channels
+- Add exponential backoff retry strategy for processing messages from RabbitMQ channels
+
+Both of these features can be enabled by providing the following flags in `config.edn`.
+
+```
+:stream-router  {:default  {:application-id       "test"
+                              :bootstrap-servers    "localhost:9092"
+                              :stream-threads-count [1 :int]
+                              :origin-topic         "topic"
+                              :upgrade-from         "1.1"
+                              :channels             {:channel                    {:worker-count [10 :int]
+                                                                                  :retry        {:count   [5 :int]
+                                                                                                 :enabled [true :bool]}}
+                                                     :with-delay                 {:worker-count [10 :int]
+                                                                                  :retry        {:count   [5 :int]
+                                                                                                 :enabled [true :bool]}
+                                                                                  :channel-delay-ms [1000 :int]}
+                                                     :with-custom-timeout        {:worker-count [10 :int]
+                                                                                  :retry        {:count   [5 :int]
+                                                                                                 :enabled [true :bool]
+                                                                                                 :queue-timeout-ms [2000 :int]}}
+                                                     :with-exponential-retry     {:worker-count [10 :int]
+                                                                                  :retry        {:count   [5 :int]
+                                                                                                 :enabled [true :bool]
+                                                                                                 :queue-timeout-ms [1000 :int]
+                                                                                                 :exponential-backoff-enabled [true :bool]}}}}}
+```
+_Note: Alpha features are experimental features and SHOULD NOT be used until they're stable._
+
+
 ## Contribution
 - For dev setup and contributions please refer to CONTRIBUTING.md
 

src/ziggurat/messaging/producer.clj

@@ -99,8 +99,10 @@
   (int (* (- (Math/pow 2 (-  retry-count message-retry-count)) 1) queue-timeout-ms)))
 
 (defn get-queue-timeout-ms [topic-entity channel message]
-  "Get queue timeout from config. It will use channel queue-timeout-ms if defined, otherwise it will use rabbitmq delay queue-timeout-ms.
-  If exponential-backoff-enabled is true, queue-timeout-ms will be exponential with formula (2^n)-1, n is message retry-count."
+  "Get queue timeout from config. It will use channel `queue-timeout-ms` if defined, otherwise it will use rabbitmq delay `queue-timeout-ms`.
+   If `exponential-backoff-enabled` is true, `queue-timeout-ms` will be exponential with formula `(2^n)-1`, where `n` is message retry-count.
+
+   _NOTE: Exponential backoff for channel retries is an experimental feature. It should not be used until released in a stable version._"
   (let [queue-timeout-ms (-> (rabbitmq-config) :delay :queue-timeout-ms)
         channel-queue-timeout-ms (get-channel-retry-queue-timeout-ms topic-entity channel)
         exponential-backoff-enabled (channel-retries-exponential-backoff-enabled topic-entity channel)]