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GitLab Discovery

The GitLab integration has a special entity provider for discovering catalog entities from GitLab. The entity provider will crawl the GitLab instance and register entities matching the configured paths. This can be useful as an alternative to static locations or manually adding things to the catalog.

To use the discovery provider, you'll need a GitLab integration set up with a token. Then you can add a provider config per group to the catalog configuration:

catalog:
  providers:
    gitlab:
      yourProviderId:
        host: gitlab-host # Identifies one of the hosts set up in the integrations
        branch: main # Optional. Uses `master` as default
        group: example-group # Optional. Group and subgroup (if needed) to look for repositories. If not present the whole project will be scanned
        entityFilename: catalog-info.yaml # Optional. Defaults to `catalog-info.yaml`
        projectPattern: /[\s\S]*/ # Optional. Filters found projects based on provided patter. Defaults to `/[\s\S]*/`, what means to not filter anything
        schedule: # optional; same options as in TaskScheduleDefinition
          # supports cron, ISO duration, "human duration" as used in code
          frequency: { minutes: 30 }
          # supports ISO duration, "human duration" as used in code
          timeout: { minutes: 3 }

As this provider is not one of the default providers, you will first need to install the gitlab catalog plugin:

# From the Backstage root directory
yarn add --cwd packages/backend @backstage/plugin-catalog-backend-module-gitlab

Once you've done that, you'll also need to add the segment below to packages/backend/src/plugins/catalog.ts:

/* packages/backend/src/plugins/catalog.ts */

import { GitlabDiscoveryEntityProvider } from '@backstage/plugin-catalog-backend-module-gitlab';

const builder = await CatalogBuilder.create(env);
/** ... other processors and/or providers ... */
builder.addEntityProvider(
  ...GitlabDiscoveryEntityProvider.fromConfig(env.config, {
    logger: env.logger,
    // optional: alternatively, use scheduler with schedule defined in app-config.yaml
    schedule: env.scheduler.createScheduledTaskRunner({
      frequency: { minutes: 30 },
      timeout: { minutes: 3 },
    }),
    // optional: alternatively, use schedule
    scheduler: env.scheduler,
  }),
);

Alternative processor

catalog:
  locations:
    - type: gitlab-discovery
      target: https://gitlab.com/group/subgroup/blob/main/catalog-info.yaml

As alternative to the entity provider GitlabDiscoveryEntityProvider you can still use the GitLabDiscoveryProcessor.

Note the gitlab-discovery type, as this is not a regular url processor.

The target is composed of three parts:

• The base URL, https://gitlab.com in this case
• The group path, group/subgroup in this case. This is optional: If you omit this path the processor will scan the entire GitLab instance instead.
• The path within each repository to find the catalog YAML file. This will usually be /blob/main/catalog-info.yaml, /blob/master/catalog-info.yaml or a similar variation for catalog files stored in the root directory of each repository. If you want to use the repository's default branch use the * wildcard, e.g.: /blob/*/catalog-info.yaml

Finally, you will have to add the processor in the catalog initialization code of your backend.

// In packages/backend/src/plugins/catalog.ts
+import { GitLabDiscoveryProcessor } from '@backstage/plugin-catalog-backend-module-gitlab';

 export default async function createPlugin(
   env: PluginEnvironment,
 ): Promise<Router> {
   const builder = await CatalogBuilder.create(env);
+  builder.addProcessor(
+    GitLabDiscoveryProcessor.fromConfig(env.config, { logger: env.logger })
+  );

If you don't want create location object if file with component definition do not exists in project, you can set the skipReposWithoutExactFileMatch option. That can reduce count of request to gitlab with 404 status code.