[Async] http-get entrypoint

[mouligno]

:rainbow: Feature

As an Async API owner, I want to expose my events events to external consumers not able to process streams of data (provided by protocols such as Websocket and SSE).

As an Async API Consumer, I want to retrieve messages from a GET call.

:sunrise_over_mountains: Additional information

• Transaction id is sent to backend in order to let it handle offset of messages.
  • to be used as consumer id from kafka connector (#8245)
• Max retrieved messages default value - 500
• First call, 0-499 messages, 2nd 500-999 ....
• Append messages to create an array of messages - hard coded formatting as a first step
• Can be tested with mock endpoint

Out of scope :

• specific offset selection
• Timeframe selection
• Message pagination

Example of initialization - https://github.com/gravitee-io/gravitee-poc-sme/blob/master/src/main/java/io/gravitee/poc/sme/gateway/connector/endpoint/async/impl/KafkaEndpointAsyncConnector.java

:superhero: Acceptance criteria

• [ ] Given an Async API then I can retrieve messages using a http-get entrypoint

[LiliaEn]

Tested on the default env- 3.20.0 version The following scenarios were covered:

• Creating an async API with http-get entrypoint and mock endpoint and messages configuration;
• Creating a plan and publishing it
• Calling the API and checking that messages are retrieved correctly;
• Using query parameters like "limit" and "cursor" to check that the messages are received accordingly
• Checking that the message duration is applied correctly

[LiliaEn]

Testing with Kafka endpoint will be covered in this ticket: https://graviteecommunity.atlassian.net/browse/APIM-59