Warning |
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This spike is a WIP |
Jira |
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server | ONAP Jira |
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serverId | 425b2b0a-557c-3c0c-b515-579789cceedb |
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key | CPS-821 |
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Description/Scope
The scope of this spike is to ascertain:
- How to use messaging (producer, agree topic etc))
- Using existing rest endpoint with additional flag indicating async response
- Also consider asynchronous request option using messaging in the proposal
Associated Jira Created for Implementation
Jira |
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server | ONAP Jira |
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columnIds | issuekey,summary,issuetype,created,updated,duedate,assignee,reporter,priority,status,resolution |
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columns | key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution |
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maximumIssues | 20 |
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jqlQuery | key = CPS-828 |
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serverId | 425b2b0a-557c-3c0c-b515-579789cceedb |
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Issues/Decisions
# | Issue | Decision | Notes/Jira |
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1 | What topic to use? proposed ncmp-async-xxx |
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2 | Are adding a new REST endpoint for async or modifying an existing endpoint? |
| Jira |
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server | ONAP Jira |
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serverId | 425b2b0a-557c-3c0c-b515-579789cceedb |
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key | CPS-830 |
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3 | Agree URL for async once #2 is clarified |
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4 | passthrough request need to be able to handle different response types (using accept header) but the async option would have a fixed and possibly different response type. |
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5 | How many messages are we expecting at peak time? |
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6 | Should we create a standalone app to demo or are tests sufficient? |
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7 | Do we need to persist the generated requestID? |
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8 | Will cps-temporal require the requestID? |
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Proposed Diagram
draw.io Diagram |
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border | true |
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diagramName | CPS-821 |
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simpleViewer | false |
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width | |
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links | auto |
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tbstyle | top |
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lbox | true |
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diagramWidth | 771 |
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revision | 5 |
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Rest Endpoint with Async Flag
Current | Proposed |
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<ncmp>/v1/ch/PNFDemo/data/ds/ncmp-datastore:passthrough-running?resourceIdentifier=stores:bookstore | <ncmp>/v1/ch/PNFDemo/data/async/ds/ncmp-datastore:passthrough-running?resourceIdentifier=stores:bookstore |
Kafka config & Implementation
Example of Existing Consumer (Java)
The below code snippet taken from cps-temporal can be used in the same way in NCMP to listen to message from DMI substituting the topics and errorHandler
Code Block |
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language | java |
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title | Example Listener (Java, cps-temporal) |
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collapse | true |
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/**
* Consume the specified event.
*
* @param cpsDataUpdatedEvent the data updated event to be consumed and persisted.
*/
@KafkaListener(topics = "${app.listener.data-updated.topic}", errorHandler = "dataUpdatedEventListenerErrorHandler")
public void consume(final CpsDataUpdatedEvent cpsDataUpdatedEvent) {
log.debug("Receiving {} ...", cpsDataUpdatedEvent);
// Validate event envelop
validateEventEnvelop(cpsDataUpdatedEvent);
// Map event to entity
final var networkData = this.cpsDataUpdatedEventMapper.eventToEntity(cpsDataUpdatedEvent);
log.debug("Persisting {} ...", networkData);
// Persist entity
final var persistedNetworkData = this.networkDataService.addNetworkData(networkData);
log.debug("Persisted {}", persistedNetworkData);
} |
Example of Existing Consumer (Config)
Code Block |
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language | yml |
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title | Example of Existing Consumer (Config) |
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collapse | true |
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# ============LICENSE_START=======================================================
# Copyright (c) 2021 Bell Canada.
# ================================================================================
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============LICENSE_END=========================================================
# Spring profile configuration for sasl ssl Kafka
spring:
kafka:
bootstrap-servers: ${KAFKA_BOOTSTRAP_SERVER}
security:
protocol: SASL_SSL
ssl:
trust-store-type: JKS
trust-store-location: ${KAFKA_SSL_TRUST_STORE_LOCATION}
trust-store-password: ${KAFKA_SSL_TRUST_STORE_PASSWORD}
properties:
sasl.mechanism: SCRAM-SHA-512
sasl.jaas.config: ${KAFKA_SASL_JAAS_CONFIG}
ssl.endpoint.identification.algorithm: |
Example of Existing Producer (Java)
Example of Existing Producer (Config)
Example of Kafka Docker-Compose
Code Block |
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language | yml |
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title | Kafka Docker Example |
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collapse | true |
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kafka:
image: confluentinc/cp-kafka:6.1.1
container_name: kafka
ports:
- "19092:19092"
depends_on:
- zookeeper
environment:
KAFKA_BROKER_ID: 1
KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092,CONNECTIONS_FROM_HOST://localhost:19092
KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: PLAINTEXT:PLAINTEXT,CONNECTIONS_FROM_HOST:PLAINTEXT
KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1 |
Response types for passthrough
Will we be able to handle everything "as-is"?
Future (or alternative)
What are Futures?
CompletableFuture (Java8+)
Java 8 introduced the CompletableFuture class. Along with the Future interface, it also implemented the CompletionStage interface. This interface defines the contract for an asynchronous computation step that we can combine with other steps.
CompletableFuture is at the same time a building block and a framework, with about 50 different methods for composing, combining, and executing asynchronous computation steps and handling errors.
Code Block |
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language | java |
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theme | Eclipse |
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title | Simple Future Example |
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collapse | true |
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public Future<String> calculateAsync() throws InterruptedException {
CompletableFuture<String> completableFuture = new CompletableFuture<>();
Executors.newCachedThreadPool().submit(() -> {
Thread.sleep(500);
completableFuture.complete("Hello");
return null;
});
return completableFuture;
} |
source: https://www.baeldung.com/java-completablefuture
Alternatives
Code Block |
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language | java |
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title | Thread Example |
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collapse | true |
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int number = 20;
Thread newThread = new Thread(() -> {
System.out.println("Factorial of " + number + " is: " + factorial(number));
});
newThread.start(); |
# | Type | Pros | Cons | Recommend |
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1 | Future |
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2 | Thread |
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RequestID Generation
Type | Method | Ease of implementation | Recommend |
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UUID | String uniqueID = UUID.randomUUID().toString();
| Easy | Y |
Custom | We generate our own | Medium - Hard | N |
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Async Request Option using Messaging
Demo/Test