/cloudevents-asyncapi-converter

CloudEvents payload to AsyncAPI conversion tool for ABAP, written in TypeScript

Primary LanguageTypeScriptApache License 2.0Apache-2.0

REUSE status

Converter for CloudEvents to AsyncAPI

Converter for CloudEvents to AsyncAPI is a Node.js library and CLI application that converts any event payload conforming to the CloudEvents specification into an AsyncAPI catalog which can be used in an ABAP environment to generate an Event Consumption Model.

Find the official web application hosted on GitHub Pages at https://sap.github.io/cloudevents-asyncapi-converter.

Note

CloudEvents® is a registered trademark of The Linux Foundation.

Installation

Prerequisites

  • Node.js version 20.x or above
  • npm version 9.x or above

Steps

  1. Clone the repository
  2. Navigate to the repository's root folder
  3. Install the package and its dependencies
npm install && npm install -g .

Tip

If you wish to install and use the package locally (i.e. not system-wide), simply drop the second npm install command.

Usage

Command Line

To convert a CloudEvents payload in JSON format to a corresponding AsyncAPI catalog, this package offers the following command:

ce2async [input path] [--output|-o path] [--version|-v version] [--help]

  • Arguments:

    • input
      Path to the input file containing the CloudEvents payload. If not specified, the input is read from stdin instead. If the payload is invalid, the command will fail with a non-zero exit code and print an error message to stderr.

  • Options:

    • --output, -o
      Path to the output file that will contain the AsyncAPI catalog. If not specified, the output is written to stdout instead.

    • --version, -v
      Version of the AsyncAPI specification to use for conversion. Presently, only version 2.0 for AsyncAPI 2.0.x is supported.

    • --help
      Help page for this command.

Tip

In case you only installed the package locally, you must run the command with npx from within the repository.

Example

As an example, suppose you want to convert the payload in examples/input.json to an AsyncAPI 2.0.x catalog file. To achieve that, simply run

ce2async examples/input.json -o output.json

The file output.json now contains the corresponding AsyncAPI catalog, exactly as in examples/output.json.

Or alternatively, to read some event payload from stdin and write the converted result to stdout, instead run

echo '{"type":"sap.eee.iwxbe.testproducer.v1.Event.Conversion","specversion":"1.0","source":"/default/sap.eee/XXXCLNT400","id":"42010aef-0cee-1edb-879d-6a2c14dc9326","time":"2020-11-02T09:10:57Z","datacontenttype":"application/json","data":{"Amount":100.0,"Currency":"KWD","Quantity":1000.0,"Unit":"KG","Alpha":"1"}}' | ce2async

API

Although this package is intended to be primarily used as a CLI application, it also provides an API to perform the conversion programmatically. As to that, the package exports a single class PayloadConverter, which offers the following methods:

  • Static Methods:

    • create(version?: string): PayloadConverter;
      Creates a new instance of a PayloadConverter for the optionally specified AsyncAPI specification version, assuming v2.0 by default. Throws an error when version is invalid or not supported.

  • Instance Methods:

    • convert(payload: object): object;
      Converts a CloudEvents payload object to a corresponding AsyncAPI catalog object, using the converter's specification version. Throws an error when payload is malformed according to the CloudEvents specification.

    • convertAsString(payload: string): string;
      Functions like convert(...) but accepts a JSON string as an input, which is parsed before converting. Returns the output as a JSON string as well.

Example

import { PayloadConverter } from 'cloudevents-asyncapi-converter';

const converter = PayloadConverter.create();

const input = '...'; // some CloudEvents JSON string
try {
    const output = converter.convertAsString(input);
    // conversion succeeded
} catch (error) {
    // conversion failed
}

Limitations

The payload converter only generates a rough AsyncAPI catalog solely based on the CloudEvents payload by inferring data types in a naïve manner. Consequently, it exhibits some limitations that require manual adjustments to the payload prior to conversion or to the resulting catalog.

  • Properties with value null or empty objects {} in the payload are currently rejected by the converter.

  • String properties are not analyzed with regards to their data format and have none assigned.

  • Numeric properties always receive the data format decimal by the converter.

  • For compositions of objects, the converter is currently unable to link parent and child schemas through references. Instead, it treats them independently of each other.

    Details

    Suppose your payload has nested schemas like the ComplexCollection below, containing objects of the type Complex.

    // ...
"ComplexCollection": [
  {
    "Amount": 100.000,
    "Currency": "KWD",
    "Quantity": 1000.000,
    "Unit": "KG",
    "Alpha": "1"
  },
  // ...
],
"Complex": {
  "Amount": 0.000,
  "Currency": "KWD",
  "Quantity": 0.000,
  "Unit": "KG",
  "Alpha": "1"
},
// ...

    Rather than linking the items of ComplexCollection to the Complex schema, the converter creates individual schemas for each object.

    // ...
"schemas": {
  "ComplexCollection": {
    "type": "array",
    "items": {
      "$ref": "#/components/schemas/sap_eee_iwxbe_testproducer_v1_Event_DeepStructure_ComplexCollection"
    }
  },
  "Complex": {
    "type": "object",
    "$ref": "#/components/schemas/sap_eee_iwxbe_testproducer_v1_Event_DeepStructure_Complex"
  },
  // ...
  "sap_eee_iwxbe_testproducer_v1_Event_DeepStructure_ComplexCollection": {
    "type": "object",
    "properties": {
      "Amount": {
        "type": "number",
        "format": "decimal"
      },
      "Currency": {
        "type": "string"
      },
      "Quantity": {
        "type": "number",
        "format": "decimal"
      },
      "Unit": {
        "type": "string"
      },
      "Alpha": {
        "type": "string"
      }
    }
  },
  "sap_eee_iwxbe_testproducer_v1_Event_DeepStructure_Complex": {
    "type": "object",
    "properties": {
      "Amount": {
        "type": "number",
        "format": "decimal"
      },
      "Currency": {
        "type": "string"
      },
      "Quantity": {
        "type": "number",
        "format": "decimal"
      },
      "Unit": {
        "type": "string"
      },
      "Alpha": {
        "type": "string"
      }
    }
  }
}

Support, Feedback, Contributing

This project is open to feature requests/suggestions, bug reports etc. via GitHub issues. Contribution and feedback are encouraged and always welcome. For more information about how to contribute, the project structure, as well as additional contribution information, see our Contribution Guidelines.

Security / Disclosure

If you find any bug that may be a security problem, please follow our instructions at in our security policy on how to report it. Please do not create GitHub issues for security-related doubts or problems.

Code of Conduct

We as members, contributors, and leaders pledge to make participation in our community a harassment-free experience for everyone. By participating in this project, you agree to abide by its Code of Conduct at all times.

Licensing

Copyright 2024 SAP SE or an SAP affiliate company and cloudevents-asyncapi-converter contributors. Please see our LICENSE for copyright and license information. Detailed information including third-party components and their licensing/copyright information is available via the REUSE tool.