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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. Used to discover on a specific branch
fallbackBranch: main # Optional. Fallback to be used if there is no default branch configured at the Gitlab repository. It is only used, if `branch` is undefined. Uses `master` as default
skipForkedRepos: false # Optional. If the project is a fork, skip repository
group: example-group # Optional. Group and subgroup (if needed) to look for repositories. If not present the whole instance 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]*`, which 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 your Backstage root directory
yarn --cwd packages/backend add @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.

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.

If you don't want to create location object if the project is a fork, you can set the skipForkedRepos option.