[DOC] Update DCAE SDK doc for direct Kafka usage

Update DCAE SDK doc for direct Kafka usage instead of dmaap

Issue-ID: DCAEGEN2-3405
Change-Id: I8999d6359ccfc96514e195b4c6664cf19e56f29b
Signed-off-by: sushant53 <sushant.jadhav@t-systems.com>

2 files changed, 77 insertions, 2 deletions

diff --git a/docs/sections/sdk/apis.rst b/docs/sections/sdk/apis.rst
index 94be6fdd..f63ca4e3 100644
--- a/docs/sections/sdk/apis.rst
+++ b/docs/sections/sdk/apis.rst
@@ -121,8 +121,8 @@ Library to generate and match cryptography password using BCrypt algorithm
 
 Can be used like maven dependency to match generated password.
 
-dmaap-client - a DMaaP MR client
---------------------------------
+dmaap-client - a DMaaP MR client (upto version 1.9.3)
+-----------------------------------------------------
 After parsing CBS sink definitions you will get a Source or Sink value object. It can be then directly used to communicate with DMaaP Message Router REST API.
 
 Writing message publisher
@@ -340,6 +340,79 @@ Configure request for authorized topics
 AAF Credentials are optional for subscribe/publish requests.
 Username and password are used for basic authentication header during sending HTTP request to dmaap-mr.
 
+dmaap-client - a Kafka client (For version 1.9.4)
+----------------------------------------------------
+
+Version 1.9.4 has tried to keep method signatures same as previous version so as to reduce impact on services using previous version of this library. You can create publisher and subscriber like it is done using previous version of this library (as shown above).
+
+Alternatively, version 1.9.4 of the library provides another constructor for creating them which is suggested to be used by new services.
+
+********************************
+Writing Publisher and subscriber
+********************************
+**Writing message publisher**
+
+.. code-block:: java
+
+    final MessageRouterPublisher publisher = new MessageRouterPublisherImpl();
+    final MessageRouterSink sinkDefinition; //... Sink definition obtained by parsing CBS response
+    final MessageRouterPublishRequest request = ImmutableMessageRouterPublishRequest.builder()
+            .sinkDefinition(sinkDefinition)
+            .build();
+
+**Writing message subscriber**
+
+.. code-block:: java
+
+    final MessageRouterPublisher subscriber = new MessageRouterSubscriberImpl();
+    final MessageRouterSource sourceDefinition; //... Source definition obtained by parsing CBS response
+    final MessageRouterSubscribeRequest request = ImmutableMessageRouterSubscribeRequest.builder()
+            .sourceDefinition(sourceDefinition)
+            .build();
+
+********************************
+Closing Publisher and subscriber
+********************************
+From version 1.9.4, the service needs to explicitly close the publisher and subscriber to avoid resource leakage. New close methods are introduced to do the same.
+
+**Closing message publisher**
+
+.. code-block:: java
+
+    publisher.close();
+
+**Closing message subscriber**
+
+.. code-block:: java
+
+    subscriber.close();
+
+******************************
+Environment variables required
+******************************
+If the service uses sdk library version 1.9.4, the service needs to ensure that two new environment variables are declared. These two environment variables are mandatory and are required to establish connection with kafka. They are as follows:
+
+.. code-block:: yaml
+
+    - name: BOOTSTRAP_SERVERS
+      value: onap-strimzi-kafka-bootstrap:9092
+    - name: JAAS_CONFIG
+	  valueFrom:
+        secretKeyRef:
+          key: sasl.jaas.config
+          name: strimzi-kafka-admin
+
+The service can also provide optional standard Kafka properties as environment variables to override the default values used by the library. Such property names must be prefixed with string "kafka.". An example is given below:
+
+.. code-block:: yaml
+
+    # To override Kafka property "max.poll.interval.ms"
+    - name: kafka.max.poll.interval.ms
+      value: 35000
+    # To override Kafka property "heartbeat.interval.ms"
+    - name: kafka.heartbeat.interval.ms
+      value: 50000
+
 hvvesclient-producer - a reference Java implementation of High Volume VES Collector client
 ------------------------------------------------------------------------------------------
 This library is used in xNF simulator which helps us test HV VES Collector in CSIT tests. You may use it as a reference when implementing your code in non-JVM language or directly when using Java/Kotlin/etc.
diff --git a/docs/sections/sdk/architecture.rst b/docs/sections/sdk/architecture.rst
index dd74e052..c0c55f54 100644
--- a/docs/sections/sdk/architecture.rst
+++ b/docs/sections/sdk/architecture.rst
@@ -90,6 +90,8 @@ DmaaP-MR Client
     * Support for authenticated topics pub/sub
     * Standardized logging
 
+    From version 1.9.4, as DMaaP is announced as deprecated project, this library uses Kafka directly instead of DMaaP APIs.
+
 ConfigBindingService Client
 +++++++++++++++++++++++++++
     Thin client wrapper to fetch configuration based on exposed properties during deployment from the file on a configMap/volume or from CBS api if configMap/volume does not exist. Provides option to periodically query and capture new configuration changes if any should be returned to application.