Merge branch 'users/komakkar/SOPTopic' into 'master'

Adding playbook for Topic Creation and Consumption

See merge request !62

provider/notification-azure/SOP_FOR_TOPIC_CREATION.md

+# SOPs for Creating a new Topic and Adding subscriber for it. 
+
+### Introduction
+Notification service is invoked by PubSub called [Event Grid](https://docs.microsoft.com/en-us/azure/event-grid/).
+This document describes how to create a topic, publish to it and listen to it. 
+
+### How to create the Topic and start using it.
+#### 1. Create Event Grid Topic. 
+Following this will enable creation of topic in all data partitions. 
+1. Create a Topic. [Reference](https://community.opengroup.org/osdu/platform/deployment-and-operations/infra-azure-provisioning/-/blob/master/infra/templates/osdu-r3-mvp/data_partition/main.tf#L301)
+2. Assign the Service Principals of service the role "EventGrid EventSubscription Contributor". [Reference](https://community.opengroup.org/osdu/platform/deployment-and-operations/infra-azure-provisioning/-/merge_requests/32)
+3. Identify the fully qualified topic name and it's alias. The fully qualified topic name is the one you see on the Azure portal. An example is "osdu-env-dp1env-as12-grid-recordstopic". The alias could be recordstopic. Make sure the alias ends with topic. Invalid topic names will be "testtopic1", "test_topic", "testtopics" etc. 
+4. Create secrets in Common Resources Key Vault that helps your service identify the event grid topic end point. [Reference](https://community.opengroup.org/osdu/platform/deployment-and-operations/infra-azure-provisioning/-/merge_requests/30/diffs)
+Make sure you name them in the format  "eventgrid-\<alias\>" and "eventgrid-\<alias\>-accesskey". For example, if the topic alias is "testtopic", the keys should look like "eventgrid-testtopic-accesskey" and "eventgrid-testtopic". 
+
+#### 2. Make partition service aware of the new topic.
+Partition service maintains the configuration for each infrastructure component. 
+
+For all the tenants, add the new topic information. [Reference](https://community.opengroup.org/osdu/platform/deployment-and-operations/infra-azure-provisioning/-/merge_requests/101)
+This is to be done per partition per deployment. 
+
+#### 3. Make Register service aware of the new Topic 
+1. Add the topic alias to [topics.json](https://community.opengroup.org/osdu/platform/system/register/-/blob/master/provider/register-azure/src/main/resources/topics.json). Make sure you fill in the values of description, state and examples to ensure that the get Topic API contract is not broken. 
+
+#### 4. Publish to Event Grid Topic.
+Using core-lib-azure [Event Grid facade](https://community.opengroup.org/osdu/platform/system/lib/cloud/azure/os-core-lib-azure/-/blob/master/src/main/java/org/opengroup/osdu/azure/eventgrid/EventGridTopicStore.java), you can publish the events. [Reference](https://community.opengroup.org/osdu/platform/system/storage/-/blob/master/provider/storage-azure/src/main/java/org/opengroup/osdu/storage/provider/azure/MessageBusImpl.java#L67)
+
+#### 5. Steps to Subscribe
+1. Register your subscriber with Register Service. You will need to expose two endpoints
+	
+	__Get Endpoint__: for a Handshake/challenge response. [Reference](https://community.opengroup.org/osdu/platform/system/register/-/blob/master/register-core/src/main/java/org/opengroup/osdu/register/api/test/SubscriberListenerApi.java#L52)
+    
+    __Post Endpoint__: for receiving notifications. [Reference](https://community.opengroup.org/osdu/platform/system/register/-/blob/master/register-core/src/main/java/org/opengroup/osdu/register/api/test/SubscriberListenerApi.java#L65)
+
+2. For onboarding a service, you have to initiate a handshake, per data partition.
+3. The authZ mechanism for the Get endpoint, isn't done by entitlement service.The secret used during the handshake should be used by the service to authorize the jwt.  
+ 
+### Security compliance 
+1. Please refrain from printing fully qualified topic name in the logs.  
+ 
+### FAQs
+1. __Event Grid is push endpoint. I have need for a pull mechanism, how can I achieve it?__
+Notification service is not equiped for pull mechanism yet. You can publish to pull based products like Service Bus. 
+In case you want both pull and push subscribers, notification service can be an interface for only push (Event Grid). 
+A subscriber to that Event Grid Topic could be a Service Bus Topic. This Service Bus Topic in turn can have multiple 
+pull subscribers. [Reference](https://community.opengroup.org/osdu/platform/deployment-and-operations/infra-azure-provisioning/-/merge_requests/97/diffs)
+
+2. __Does notification service provide filtering capability?__
+Not today. 
+
+3. __When should I create a topic vs using an existing one?__
+If the nature of messages and subscribers overlap completely with an existing topic, re-use it.
+
+4. __Are there different Topics for OSDU Platform and it's consumers?__
+The need is getting evaluated. 
+
+5. __The topics.json isn't scalable model__
+We are evaluating the need for the bringing up a store.
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