README updated, Properties provisioned

provider/notification-gcp/README.md

@@ -4,13 +4,39 @@ notification-gcp is a [Spring Boot](https://spring.io/projects/spring-boot) serv
 ## Getting Started
 These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.
 
-### Requirements
+# Features of implementation
+This is a universal solution created using EPAM OQM mapper technology.
+It allows you to work with various implementations of message brokers.
+
+## Limitations of the current version
+
+In the current version, the OQM mapper is equipped with 2 drivers to the message brokers:
+
+- Google PubSub; 
+- RabbitMQ
+
+## Extensibility
+
+To use any other message broker, implement a driver for it. With an extensible set of drivers, the solution is unrestrictedly universal and portable without modification to the main code.
+
+Mapper support "multitenancy" with flexibility in how it is implemented.
+It switches between datasources of different tenants due to the work of a bunch of classes that implement the following interfaces:
+
+- Destination - takes a description of the current context, e.g., "data-partition-id = opendes"
+- DestinationResolver – accepts Destination, finds the resource, connects, and returns Resolution
+- DestinationResolution – contains a ready-made connection, the mapper uses it to get to data
+
+# Settings and Configuration
+## Requirements
+### Mandatory
 * Java 8
 * [Maven 3.6.0+](https://maven.apache.org/download.cgi)
+
+### for Google Cloud only
 * GCloud command line tool
 * GCloud access to opendes project
 
-### General Tips
+## General Tips
 
 **Environment Variable Management**
 The following tools make environment variable configuration simpler
@@ -22,16 +48,45 @@ This project uses [Lombok](https://projectlombok.org/) for code generation. You
  - [Intellij configuration](https://projectlombok.org/setup/intellij)
  - [VSCode configuration](https://projectlombok.org/setup/vscode)
 
-### Installation
-In order to run the service locally or remotely, you will need to have the following environment variables defined.
+## Mapper tuning mechanisms
+
+This service uses specific implementation of DestinationResolver  based on the tenant information provided by the OSDU Partition service.
+A total of 2 resolvers are implemented, which are divided into two groups:
+### for universal technologies:
+- for RabbitMQ: mappers/oqm/MqTenantOqmDestinationResolver.java
+
+#### Their algorithms are as follows:
+- incoming Destination carries data-partition-id
+- resolver accesses the Partition service and gets PartitionInfo
+- from PartitionInfo resolver retrieves properties for the connection: URL, username, password etc.
+- resolver creates a data source, connects to the resource, remembers the datasource
+- resolver gives the datasource to the mapper in the Resolution object
+
+### for native Google Cloud technologies:
+- for PubSub: mappers/oqm/PsTenantOqmDestinationResolver.java
+
+#### Their algorithms are similar,
+Except that they do not receive special properties from the Partition service for connection, because the location of the resources is unambiguously known - they are in the GCP project. And credentials are also not needed - access to data is made on behalf of the Google Identity SA under which the service itself is launched. Therefore, resolver takes only the value of the **projectId** property from PartitionInfo and uses it to connect to a resource in the corresponding GCP project.
+
+# Configuration
+
+## Service Configuration
+In order to run the service locally or remotely, define the following environment variables.
+Most of them are common to all hosting environments, but there are properties that are only necessary when running in Google Cloud.
+
+#### Common properties for all environments
 
 | name | value | description | sensitive? | source |
 | ---  | ---   | ---         | ---        | ---    |
 | `APP_ENTITLEMENTS` | ex `https://entitlements.com/entitlements/v1` | Entitlements API endpoint | no | output of infrastructure deployment |
 | `APP_REGISTER` | ex `https://register.com/api/register/v1` | Storage API endpoint | no | output of infrastructure deployment |
+| `PARTITION_API` | ex `http://localhost:8081/api/partition/v1` | Partition service endpoint | no | - |
+
+#### For Google Cloud only
+| name                         | value                                 | description                                                        | sensitive? | source                                            |
+|------------------------------|---------------------------------------|--------------------------------------------------------------------|------------|---------------------------------------------------|
 | `APP_PROJECT` | ex `opendes` | Google Cloud Project Id | no | output of infrastructure deployment |
 | `APP_AUDIENCES` | ex `*****.apps.googleusercontent.com` | Client ID for getting access to cloud resources | yes | https://console.cloud.google.com/apis/credentials |
-| `PARTITION_API` | ex `http://localhost:8081/api/partition/v1` | Partition service endpoint | no | - |
 
 **System Environment required to run service**
 
@@ -39,7 +94,115 @@ In order to run the service locally or remotely, you will need to have the follo
 | ---  | ---   | ---         | ---        | ---    |
 | `SPRING_PROFILES_ACTIVE` | `local` | spring active profile | no |
 
-### Run Locally
+## Configuring mappers Datasources
+When using non-Google-Cloud-native technologies, property sets must be defined on the Partition service as part of PartitionInfo for each Tenant.
+
+#### for OQM - RabbitMQ:
+**prefix:** `register.oqm.rabbitmq`
+It can be overridden by:
+
+- through the Spring Boot property `oqm.rabbitmq.partitionPropertiesPrefix`
+- environment variable `OQM_RABBITMQ_PARTITIONPROPERTIESPREFIX`
+
+**Propertyset** (for two types of connection: messaging and admin operations):
+
+| Property | Description |
+| --- | --- |
+| register.oqm.rabbitmq.amqp.host | messaging hostnameorIP |
+| register.oqm.rabbitmq.amqp.port | - port |
+| register.oqm.rabbitmq.amqp.path | - path |
+| register.oqm.rabbitmq.amqp.username | - username |
+| register.oqm.rabbitmq.amqp.password | - password |
+| register.oqm.rabbitmq.admin.schema | admin host schema |
+| register.oqm.rabbitmq.admin.host | - host name |
+| register.oqm.rabbitmq.admin.port | - port |
+| register.oqm.rabbitmq.admin.path | - path |
+| register.oqm.rabbitmq.admin.username | - username |
+| register.oqm.rabbitmq.admin.password | - password |
+
+<details><summary>Example of a single tenant definition</summary>
+
+```
+
+curl -L -X PATCH 'https://dev.osdu.club/api/partition/v1/partitions/opendes' -H 'data-partition-id: opendes' -H 'Authorization: Bearer ...' -H 'Content-Type: application/json' --data-raw '{
+  "properties": {
+    "register.oqm.rabbitmq.amqp.host": {
+      "sensitive": false,
+      "value": "localhost"
+    },
+    "register.oqm.rabbitmq.amqp.port": {
+      "sensitive": false,
+      "value": "5672"
+    },
+    "register.oqm.rabbitmq.amqp.path": {
+      "sensitive": false,
+      "value": ""
+    },
+    "register.oqm.rabbitmq.amqp.username": {
+      "sensitive": false,
+      "value": "guest"
+    },
+    "register.oqm.rabbitmq.amqp.password": {
+      "sensitive": true,
+      "value": "guest"
+    },
+
+     "register.oqm.rabbitmq.admin.schema": {
+      "sensitive": false,
+      "value": "http"
+    },
+     "register.oqm.rabbitmq.admin.host": {
+      "sensitive": false,
+      "value": "localhost"
+    },
+    "register.oqm.rabbitmq.admin.port": {
+      "sensitive": false,
+      "value": "9002"
+    },
+    "register.oqm.rabbitmq.admin.path": {
+      "sensitive": false,
+      "value": "/api"
+    },
+    "register.oqm.rabbitmq.admin.username": {
+      "sensitive": false,
+      "value": "guest"
+    },
+    "register.oqm.rabbitmq.admin.password": {
+      "sensitive": true,
+      "value": "guest"
+    }
+  }
+}'
+
+```
+
+</details>
+
+## Interaction with message brokers
+
+### Specifics of work through PULL subscription
+
+To receive messages from brokers, this solution uses the PULL-subscriber mechanism in the Notification service.
+This is its cardinal difference from other implementations that use PUSH-subscribers (webhooks).
+This opens a wide choice when choosing brokers.
+
+When using PULL-subscribers, there is a need to restore Notification service subscribers for each Subscription
+at the start of Notification service, as well as in the runtime,
+upon registration of a new Subscription by the Register service.
+
+To do this, a special "command" topic is involved:
+
+- the default topic name is `register-subscriber-control`.
+
+If necessary, the name of the topic can be overridden through:
+
+- Spring Boot property `oqm.registerSubscriberControlTopicName`
+- environment variable `OQM_REGISTERSUBSCRIBERCONTROLTOPICNAME`
+
+A topic is created, in its absence, when any of Register or Notification services starts.
+
+# Run and test the service
+## Running Locally
 Check that maven is installed:
 ```bash
 $ mvn --version
@@ -145,9 +308,9 @@ After the service has started it should be accessible via a web browser by visit
 
  **Entitlements configuration for integration accounts**
  
- | DE_OPS_TESTER | DE_ADMIN_TESTER | DE_EDITOR_TESTER | DE_NO_ACCESS_TESTER | 
- | ---  | ---   | ---  | ---   |
- |notification.pubsub<br/>service.entitlements.user<br/>users<br/>users.datalake.ops</br>| service.entitlements.user<br/>users<br/>users.datalake.admins</br> | service.entitlements.user<br/>users<br/>users.datalake.editors</br> | service.entitlements.user<br/>users<br/>|
+| DE_OPS_TESTER | DE_ADMIN_TESTER | DE_EDITOR_TESTER | DE_NO_ACCESS_TESTER | 
+| ---  | ---   | ---  | ---   |
+|notification.pubsub<br/>service.entitlements.user<br/>users<br/>users.datalake.ops</br>| service.entitlements.user<br/>users<br/>users.datalake.admins</br> | service.entitlements.user<br/>users<br/>users.datalake.editors</br> | service.entitlements.user<br/>users<br/>|
 
 Above variables should be configured in the release pipeline to run integration tests. You should also replace them with proper values if you wish to run tests locally.
 

provider/notification-gcp/src/main/java/org/opengroup/osdu/notification/provider/gcp/mappers/oqm/OqmConfigurationProperties.java

+package org.opengroup.osdu.notification.provider.gcp.mappers.oqm;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author Rostislav_Dublin
+ * @since 28.11.2021
+ */
+
+@Configuration
+@ConditionalOnProperty(name = "oqmDriver")
+@ConfigurationProperties(prefix = "oqm")
+@Getter
+@Setter
+public class OqmConfigurationProperties {
+
+    private String registerSubscriberControlTopicName = "register-subscriber-control";
+
+}