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Integrating Search into a plugin

The Backstage Search Platform was designed to give plugin developers the APIs and interfaces needed to offer search experiences within their plugins, while abstracting away (and instead empowering application integrators to choose) the specific underlying search technologies.

On this page, you'll find concepts and tutorials for leveraging the Backstage Search Platform in your plugin.

Providing data to the search platform

Create a collator

Knowing what a collator is will help you as you build it out.

Imagine you have a plugin that is responsible for storing FAQ snippets in a database. You want other engineers to be able to easily find your questions and answers. So that means you want them to be indexed by the search platform. Lets say the FAQ snippets can be viewed at a URL like backstage.example.biz/faq-snippets.

The search platform provides an interface (DocumentCollatorFactory from package @backstage/plugin-search-common) that allows you to do exactly that. It works by registering each of your entries as a "document" that later represents one search result each.

You can always look at a working example, e.g. StackOverflowQuestionsCollatorFactory, if you are unsure or want to follow best practices.

1. Install collator interface dependencies

We will need the interface DocumentCollatorFactory from package @backstage/plugin-search-common, so let's add it to your plugins dependencies:

# navigate to the plugin directory
# (for this tutorial our plugin lives in the backstage repo, if your plugin lives in a separate repo you need to clone that first)
cd plugins/faq-snippets

# Create a new branch using Git command-line
git checkout -b tutorials/new-faq-snippets-collator

# Install the package containing the interface
yarn add @backstage/plugin-search-common

2. Define your document type

Before we can start generating documents from our FAQ entries, we first have to define a document type containing all necessary information we need to later display our entry as search result. The package @backstage/plugin-search-common we installed earlier contains a type IndexableDocument that we can extend.

Create a new file plugins/faq-snippets/src/search/collators/FaqSnippetDocument.ts and paste the following below:

import { IndexableDocument } from '@backstage/plugin-search-common';

export interface FaqSnippetDocument extends IndexableDocument {
  answered_by: string;
}

3. Use Backstage App configuration

Your new collator could benefit from using configuration directly from the Backstage app-config.yaml file which is located on the project's root folder:

faq:
  baseUrl: https://backstage.example.biz/faq-snippets

4. Implement your collator

Imagine your FAQs can be retrieved at the URL https://backstage.example.biz/faq-snippets with following JSON response format:

{
  "items": [
    {
      "id": 42,
      "question": "What is The Answer to the Ultimate Question of Life, the Universe, and Everything?",
      "answer": "Forty-two",
      "user": "Deep Thought"
    }
  ]
}

Below we provide an example implementation of how the FAQ collator factory could look like using our new document type, placed in the plugins/faq-snippets/src/search/collators/FaqCollatorFactory.ts file:

import fetch from 'cross-fetch';
import { Logger } from 'winston';
import { Config } from '@backstage/config';
import { Readable } from 'stream';
import { DocumentCollatorFactory } from '@backstage/plugin-search-common';

import { FaqDocument } from './FaqDocument';

export type FaqCollatorFactoryOptions = {
  baseUrl?: string;
  logger: Logger;
};

export class FaqCollatorFactory implements DocumentCollatorFactory {
  private readonly baseUrl: string | undefined;
  private readonly logger: Logger;
  public readonly type: string = 'faq-snippets';

  private constructor(options: FaqCollatorFactoryOptions) {
    this.baseUrl = options.baseUrl;
    this.logger = options.logger;
  }

  static fromConfig(config: Config, options: FaqCollatorFactoryOptions) {
    const baseUrl =
      config.getOptionalString('faq.baseUrl') ||
      'https://backstage.example.biz/faq-snippets';
    return new FaqCollatorFactory({ ...options, baseUrl });
  }

  async getCollator() {
    return Readable.from(this.execute());
  }

  async *execute(): AsyncGenerator<FaqDocument> {
    if (!this.baseUrl) {
      this.logger.error(`No faq.baseUrl configured in your app-config.yaml`);
      return;
    }

    const response = await fetch(this.baseUrl);
    const data = await response.json();

    for (const faq of data.items) {
      yield {
        title: faq.question,
        location: `/faq-snippets/${faq.id}`,
        text: faq.answer,
        answered_by: faq.user,
      };
    }
  }
}

5. Test your collator

To verify your implementation works as expected make sure to add tests for it. For your convenience, there is the TestPipeline utility that emulates a pipeline into which you can integrate your custom collator.

Look at DefaultTechDocsCollatorFactory test, for an example.

6. Make your plugins collator discoverable for others

If you want to make your collator discoverable for other adopters, add it to the list of plugins integrated to search.

Building a search experience into your plugin

While the core Search plugin offers components and extensions that empower app integrators to compose a global search experience, you may find that you want a narrower search experience just within your plugin. This could be as literal as an autocomplete-style search bar focused on documents provided by your plugin (for example, the TechDocsSearch component), or as abstract as a widget that presents a list of links that are contextually related to something else on the page.

Search Experience Concepts

Knowing these high-level concepts will help you as you craft your in-plugin search experience.

  • All search experiences must be wrapped in a <SearchContextProvider>, which is provided by @backstage/plugin-search-react. This context keeps track of state necessary to perform search queries and display any results. As inputs to the query are updated (e.g. a term or filter values), the updated query is executed and results are refreshed. Check out the SearchContextValue for details.
  • The aforementioned state can be modified and/or consumed via the useSearch() hook, also exported by @backstage/plugin-search-react.
  • For more literal search experiences, reusable components are available to import and compose into a cohesive experience in your plugin (e.g. <SearchBar /> or <SearchFilter.Checkbox />). You can see all such components in Backstage's storybook.

Search Experience Tutorials

The following tutorials make use of packages and plugins that you may not yet have as dependencies for your plugin; be sure to add them before you use them!

Improved "404" page experience

Imagine you have a plugin that allows users to manage widgets. Perhaps they can be viewed at a URL like backstage.example.biz/widgets/{widgetName}. At some point, a widget is renamed, and links to that widget's page from chat systems, wikis, or browser bookmarks become stale, resulting in errors or 404s.

What if instead of showing a broken page or the generic "looks like someone dropped the mic" 404 page, you showed a list of possibly related widgets?

import { Link } from '@backstage/core-components';
import { SearchResult } from '@backstage/plugin-search';
import { SearchContextProvider } from '@backstage/plugin-search-react';

export const Widget404Page = ({ widgetName }) => {
  // Supplying this to <SearchContextProvider> runs a pre-filtered search with
  // the given widgetName as the search term, focused on search result of type
  // "widget" with no other filters.
  const preFiltered = {
    term: widgetName,
    types: ['widget'],
    filters: {},
  };

  return (
    <SearchContextProvider initialState={preFiltered}>
      {/* The <SearchResult> component allows us to iterate through results and
          display them in whatever way fits best! */}
      <SearchResult>
        {({ results }) => (
          {results.map(({ document }) => (
            <Link to={document.location} key={document.location}>
              {document.title}
            </Link>
          ))}
        )}
      <SearchResult>
    </SearchContextProvider>
  );
);

Not all search experiences require user input! As you can see, it's possible to leverage the Backstage Search Platform's frontend framework without necessarily giving users input controls.

Simple search page

Of course, it's also possible to provide a more fully featured search experience in your plugin. The simplest way is to leverage reusable components provided by the @backstage/plugin-search package, like this:

import { useProfile } from '@internal/api';
import {
  Content,
  ContentHeader,
  PageWithHeader,
} from '@backstage/core-components';
import { SearchBar, SearchResult } from '@backstage/plugin-search';
import { SearchContextProvider } from '@backstage/plugin-search-react';

export const ManageMyWidgets = () => {
  const { primaryTeam } = useProfile();
  // In this example, note how we are pre-filtering results down to a specific
  // owner field value (the currently logged-in user's team), but allowing the
  // search term to be controlled by the user via the <SearchBar /> component.
  const preFiltered = {
    types: ['widget'],
    term: '',
    filters: {
      owner: primaryTeam,
    },
  };

  return (
    <PageWithHeader title="Widgets Home">
      <Content>
        <ContentHeader title="All your Widgets and More" />
        <SearchContextProvider initialState={preFiltered}>
          <SearchBar />
          <SearchResult>
            {/* Render results here, just like above */}
          </SearchResult>
        </SearchContextProvider>
      </Content>
    </PageWithHeader>
  );
};

Custom search control surfaces

If the reusable search components provided by @backstage/plugin-search aren't adequate, no problem! There's an API in place that you can use to author your own components to control the various parts of the search context.

import { useSearch } from '@backstage/plugin-search-react';
import ChipInput from 'material-ui-chip-input';

export const CustomChipFilter = ({ name }) => {
  const { filters, setFilters } = useSearch();
  const chipValues = filters[name] || [];

  // When a chip value is changed, update the filters value by calling the
  // setFilters function from the search context.
  const handleChipChange = (chip, index) => {
    // There may be filters set for other fields. Be sure to maintain them.
    setFilters(prevState => {
      const { [name]: filter = [], ...others } = prevState;

      if (index === undefined) {
        filter.push(chip);
      } else {
        filter.splice(index, 1);
      }

      return { ...others, [name]: filter };
    });
  };

  return (
    <ChipInput
      value={chipValues}
      onAdd={handleChipChange}
      onDelete={handleChipChange}
    />
  );
};

Check out the SearchContextValue type for more details on what methods and values are available for manipulating and reading the search context.

If you produce something generic and reusable, consider contributing your component upstream so that all users of the Backstage Search Platform can benefit. Issues and pull requests welcome.

Last updated on 9/29/2022
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