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aas/Content/Streaming/Concepts/streamingoverview.htm

Building consumers to read and process messages from a stream using the GetMessages API .

How StreamingWorks:

The Streaming service provides a robust, scalable mechanism that you can use to produce and consume high volumes of data between application components.

Here's how Streaming works: a producer publishes messages to a stream, which is an append-only log. These messages are distributed among the partitions using the message's key.

Streams are divided into a number of partitions for scalability. Partitions allow you to distribute a stream by splitting messages across multiple nodes (or brokers). Each partition can be placed on a separate machine to allow multiple consumers to read a stream in parallel. Multiple consumers can read from any partition regardless of where the partition is hosted.

A consumer can read messages from one or more streams. Each message within a stream is marked with an offset value, so a consumer can pick up where it left off if it is interrupted.

You can use the Streaming service by:

A.Creating a stream using the Console or API.

B.Using a producer to publish data to the stream.

C.Building consumers to read and process messages from a stream using the GetMessages API . .

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distributed systems of native-cloud like functions that have a lot of benefit like

Resiliency and availability

Resiliency and availability refers to the ability of asystem to continue operating, despite the failure or sub-optimal performance of some of its components.

In the case of Oracle Functions:

The control plane is a set of components that manages function definitions.

The data plane is a set of components thatexecutes functions in response to invocation requests.

For resiliency and high availability, both the control plane and data plane components are distributed across different availability domains and fault domains in a region. If one of the domains ceasesto be available, the components in the remaining domains take over to ensure that function definition management and execution are not disrupted.

When functions are invoked, they run in the subnets specified for the application to which the functions belong. For resiliency and high availability, best practice is to specify a regional subnet for an application (or alternatively, multiple AD-specific subnets in different availability domains). If an availability domain specified for an application ceases to be available, Oracle Functions runs functions in an alternative availability domain.

Concurrency and Scalability

Concurrency refers to the ability of a system to run multiple operations in parallel using shared resources. Scalability refers to the ability of the system to scale capacity (both up and down) to meet demand.

In the case of Functions, when a function is invoked for the first time, the function's image is run as a container on an instance in a subnet associated with the application to which thefunction belongs. When the function is executing inside the container, the function can read from and write to other shared resources and services running in the same subnet (for example, Database as a Service). The function can also read from and write toother shared resources (for example, Object Storage), and other Oracle Cloud Services.

If Oracle Functions receives multiple calls to a function that is currently executing inside a running container, Oracle Functions automatically and seamlessly scales horizontally to serve all the incoming requests. Oracle Functions starts multiple Docker containers, up to the limit specified for your tenancy. The default limit is 30 GB of RAM reserved for function execution per availability domain, although you can request an increase to this limit. Provided the limit is not exceeded, there is no difference in response time (latency) between functions executing on the different containers.

What Is Cloud Native?

Cloud native technologies arecharacterized by the use of containers, microservices, serverless functions, development pipelines, infrastructure expressed as code, event-driven applications, and Application Programming Interfaces (APIs). Cloud native enables faster software developmentand the ability to build applications that are resilient, manageable, observable, and dynamically scalable to global enterprise levels.

When constructing a cloud-native application, you'll want to be sensitive to how back-end services communicate with each other. Ideally, the less inter-service communication, the better. However, avoidance isn't always possible as back-end services often rely on one another to complete an operation.

While direct HTTP calls between microservices are relatively simple to implement, care should be taken to minimize this practice. To start, these calls are always synchronous and will block the operation until a result is returned or the request times outs. What were once self-contained, independent services, able to evolve independently and deploy frequently, now become coupled to each other. As coupling among microservices increase, their architectural benefits diminish.

Executing an infrequent request that makes a single direct HTTP call to another microservice might be acceptable for some systems. However, high-volume calls that invoke direct HTTP calls to multiple microservices aren't advisable. They can increase latency and negatively impact the performance, scalability, and availability of your system. Even worse, a longseries of direct HTTP communication can lead to deep and complex chains of synchronous microservices calls, shown in Figure 4-9:

A message queue is an intermediary construct through which a producer and consumer pass a message. Queues implement an asynchronous, point-to-point messaging pattern.

Events

Message queuing is an effective way to implement communication where a producer can asynchronously send a consumer a message.

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Oracle Cloud Infrastructure Events enables you to create automation based on the state changes of resourcesthroughout your tenancy. Use Events to allow your development teams to automatically respond when a resource changes its state.

Here are some examples of how you might use Events:

Send a notification to a DevOps team when a database backup completes.

Convert files of one format to another when files are uploaded to an Object Storage bucket.

You can only deliver events to certain Oracle Cloud Infrastructure services with a rule. Use the following services to create actions:

Notifications

Streaming

Functions

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on/Concepts/notificationoverview.htm