Microservice pattern: Polling publisher

[iluwatar]

Description: The Polling Publisher design pattern is used within microservices architecture to allow services to periodically check for updates or changes and then publish the results to subscribers. This pattern is particularly useful for ensuring that microservices are loosely coupled and can independently manage their data refresh cycles without requiring direct communication or immediate event-based updates.

Main Elements of the Pattern:

1. Polling Service: A microservice that periodically checks for updates or changes in a specific data source.
2. Publisher: The component within the polling service that publishes the updated data to interested subscribers.
3. Subscriber: Services or components that subscribe to the updates published by the polling service.
4. Scheduler: A mechanism to trigger the polling service at regular intervals.
5. Data Source: The source from which the polling service fetches updates.
6. Communication Protocol: Defines how the polling service communicates with subscribers, typically using RESTful APIs, message brokers, or other asynchronous messaging systems.

References:

• Microservices Architecture
• Polling and Event-Based Messaging in Microservices

Acceptance Criteria:

1. Implement a basic polling service that checks for updates in a predefined data source at regular intervals.
2. Ensure the polling service can publish updates to subscribers using a RESTful API or message broker.
3. Provide a sample subscriber that demonstrates how to consume updates from the polling service.

[YashKesh]

@iluwatar what feature you wanted to add i can do

[CoderSleek]

Hey @iluwatar, I can pick this task up.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. The issue will be unassigned if no further activity occurs. Thank you for your contributions.

[CoderSleek]

still working on it, albeit a bit slow :) The stale label can be removed

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity.

[quantdevv]

@CoderSleek , are you working on this..?

[CoderSleek]

@quantdevv hey, i was working on this yes but not anymore due to my work. it's available to take up i believe.

[quantdevv]

Thanks @iluwatar @CoderSleek , i'll have a look on this.

[quantdevv]

Hey @iluwatar , i want to discuss something on this... is there any dedicated server to discuss any kind issue..?

[iluwatar]

Hey @iluwatar , i want to discuss something on this... is there any dedicated server to discuss any kind issue..?

Try Gitter channel here: https://app.gitter.im/#/room/#iluwatar_java-design-patterns:gitter.im

[quantdevv]

Hi @iluwatar , here i'm planning to implement this micro-service pattern in below architecture .. would you like to review it once..?

Here will create two services polling-service & subscriber-service. as i made two to keep it true microservice architecture.

1. polling-service -> which will handles the periodically check for update or change in datasource & schedule , polling controller alongwith rest-controller so can be tested manually... or can be used either way.

2. subscriber service -> this contains the kafka MQ , which consume the published message by polling controller & schedular ...

the dummy structure will be like this..

Data-source ------> polling service (polling schedular, controller (publish)) ----> MQ (Kafka) -----> notification

let me know if you have any suggestion on this.. or else i'll proceed with it.

[iluwatar]

Yes, sounds good @quantdevv 👍

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity.

[quantdevv]

Hi @iluwatar , please have a look to PR.