backstage-plugin-scaffolder-json-merge-actions

This is a json-merge actions plugin for the scaffolder-backend in Backstage.

This contains a collection of actions for using with the JSON Merger npm package:

• json:merge-files - JSON Merger doc
• json:merge-file - JSON Merger doc

Prerequisites

• Node must be installed in the environment your Backstage instance is running in, but it will most likely already be there since your Backstage instance runs in Node.

• Additionally, these actions use the JSON Merger npm package. It will be useful to understand how it functions as well as what options are available in the configuration.

Getting started

In the root directory of your Backstage project:

yarn add --cwd packages/backend @mdude2314/backstage-plugin-scaffolder-json-merge-actions

Add the actions you'd like to the scaffolder:

// packages/backend/src/plugins/scaffolder.ts

import {
  createJsonMergeFileAction,
  createJsonMergeFilesAction
} from '@mdude2314/backstage-plugin-scaffolder-json-merge-actions';
import { ScmIntegrations } from '@backstage/integration';
import { createBuiltinActions, createRouter } from '@backstage/plugin-scaffolder-backend';

...

const integrations = ScmIntegrations.fromConfig(env.config);
const builtInActions = createBuiltinActions({
  catalogClient,
  integrations,
  config: env.config,
  reader: env.reader
});

const actions = [
    createJsonMergeFileAction(),
    createJsonMergeFilesAction(),
  ...builtInActions
];

return await createRouter({
  logger: env.logger,
  config: env.config,
  database: env.database,
  reader: env.reader,
  catalogClient,
  actions
});

Example of using the JSON merge:

/// files/file-1.json
{ "hello": "world", "foo": ["bar", "baz"] }

/// files/file-2.json
{ "goodbye": "world", "foo": ["rab", "zab"] }

---
apiVersion: scaffolder.backstage.io/v1beta3
kind: Template
metadata:
  name: json-merge-demo
  title: My json merge template
  description: Merge JSON files in the working directory of the task
spec:
  owner: mdude2314
  type: service

  steps:
    - id: fetch-files
      name: Fetch files
      action: fetch:plain
      input:
        url: ./files # files should contain the JSON files you want to merge

    - id: merge-files
      name: Merge files
      action: json:merge
      input:
        inputFiles: ["file-1.json", "file-2.json"]
        outputFilePath: results
        outputFileName: results.json
        jsonMergeOptions: # options passed directly to the mergeFiles function
          defaultArrayMergeOperation: "concat"

Output:

/// results/results.json
{ "hello": "world", "foo": ["bar", "baz", "rab", "zab"], "goodbye": "world" }