Updated log messages to be more intuitive

Added support for kafka
Updated logging.clj file to not reject messages which contain an empty substring.
Updating Dockerfile to use the specified GLIBC_VERSION
Adding spotify docker plugin
Moving the Dockerfile to directory root.

Issue-ID: AAI-1542
Change-Id: I4c41486cb6c7698a2c2736d574721f6a5237563e
Signed-off-by: Shwetank Dave <shwetank.dave@amdocs.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/src/chameleon/kafka.clj b/src/chameleon/kafka.clj
new file mode 100644
index 0000000..ca730a1
--- /dev/null
+++ b/src/chameleon/kafka.clj
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+(ns chameleon.kafka
+  (:refer-clojure :exclude [send])
+  (:require [clojure.core.async :as ca])
+  (:import [java.util Properties]
+           [org.apache.kafka.clients.consumer KafkaConsumer]
+           [org.apache.kafka.clients.consumer ConsumerRecord]
+           [org.apache.kafka.common.serialization StringDeserializer StringSerializer Serdes]))
+
+(declare consume run-away)
+
+(defrecord CljKafkaConsumer [config topic])
+
+
+;; Public
+(def deser StringDeserializer)
+(def ser StringSerializer)
+
+(defmacro run-away
+  [name & body]
+  `(try (.start (Thread. (fn [] ~@body) ~name))
+        (catch OutOfMemoryError e#
+          (throw (ex-info {:error "Could not allocate resources for asynchronous execution"})))))
+
+(defn clj-kafka-consumer
+  "Given a config, group-id, and a topic, return a CljKafkaConsumer"
+  [config group-id topic]
+  (CljKafkaConsumer. (assoc config "group.id" group-id) topic))
+
+(defn subscribe
+  "Given a CljKafkaConsumer, a channel, and a session timeout (in
+  ms), return a channel.  The input channel is where the messages will
+  be published."
+  ([{:keys [config topic] :as conf} channel session-timeout]
+   (subscribe conf channel session-timeout "Kafka-Subscriber-Thread"))
+  ([{:keys [config topic]} channel session-timeout thread-name]
+   (let [control-channel (ca/chan (ca/dropping-buffer 1))]
+     (run-away thread-name (consume config topic channel session-timeout control-channel))
+     control-channel)))
+
+;; Private
+
+(defn- consumer-record->clojure
+  [consumer-record]
+  {:topic (.topic ^ConsumerRecord consumer-record)
+   :partition (.partition ^ConsumerRecord consumer-record)
+   :offset (.offset ^ConsumerRecord consumer-record)
+   :key (.key ^ConsumerRecord consumer-record)
+   :value (.value ^ConsumerRecord consumer-record)})
+
+(defn- send-with-sla-timeout
+  "Consumer Records will always be a sequence. Try to put a message on
+  the channel before the sla-timeout. Return true if a message was put
+  on the channel or when there were no messages to put on the
+  channel. Return false if there is a timeout."
+  [chan sla-timeout messages]
+  (if (seq messages)
+    (let [sent? (ca/alt!! [[chan messages]] :sent
+                          (ca/timeout sla-timeout) :timeout)]
+      (if (= sent? :timeout)
+        false
+        true))
+    true))
+
+(defn- as-properties
+  [m]
+  (reduce (fn [props [k v]]
+            (.setProperty ^Properties props k v)
+            props)
+          (Properties.) m))
+
+(defn- consume
+  "Consume elements from a topic and put it on the given
+  channel. Block until a given timeout to put messages on the channel
+  or put sla-exception on the control channel (channel returned by
+  this function). Once the message is put on the channel, it is
+  considered safe to update the offset of the kafka consumer.  The
+  `sla-timeout` is an agreement such that the data has to be taken off
+  the channel within the given timeout. If failed to take the data,
+  kaka consumer will be disconnected and an exception will be put on
+  the control channel."
+  [config topic chan sla-timeout control-channel]
+  (let [consumer (KafkaConsumer. ^Properties (as-properties config))]
+    (.subscribe ^KafkaConsumer consumer (list topic))
+    (loop []
+      (let [consumer-records (.poll consumer 0)]
+        (when (and (->> consumer-records
+                        (map consumer-record->clojure)
+                        (send-with-sla-timeout chan sla-timeout))
+                   (try (.commitSync consumer)
+                        true
+                        (catch Exception e
+                          (ca/>!! control-channel (.getMessage e))
+                          false)))
+          (recur))))
+    (ca/>!! control-channel :sla-timeout)
+    (.unsubscribe consumer)
+    (.close consumer)))