ApplicationSet Reference

drydock expands a deterministic local subset of Argo CD ApplicationSet generators. Unsupported generators emit diagnostics; non-strict commands keep supported generated Applications, while --strict promotes those diagnostics to errors.

Provider-backed generators are fixture-backed only. The CLI never contacts Kubernetes, Argo CD, SCM provider, pull-request, cloud, or plugin-service APIs for ApplicationSet generation.

Supported Generators

Supported local generators:

• Git directories
• Git files
• List, including elementsYaml
• Matrix
• Merge
• Fixture-backed provider generators for clusters, clusterDecisionResource, SCM provider, pull requests, and plugin generators

Supported template behavior:

• spec.goTemplate: true
• spec.goTemplateOptions, including missingkey=error
• spec.templatePatch rendered from generator params, strategic-merge-applied to the generated Application, with spec.project preserved
• Sprig-compatible functions used by Argo CD, including regexReplaceAll
• generator-level selectors
• generator-level template overrides
• generated Application.metadata.namespace set to the ApplicationSet namespace
• Argo CD’s default generated Application finalizer where applicable
• multiple supported top-level generators evaluated independently and concatenated in manifest order

Git Generators

Git directories and Git files matches are sorted by normalized relative path. Include and exclude patterns are deterministic, and exclude: true removes a path even when another pattern includes it. When a Git generator defines both directories and files, Argo CD’s directory-first dispatch is used and files are ignored.

Git files must remain under the repository root and must not traverse symlinks. YAML and JSON files may decode to a mapping document, an array of mapping documents, an empty mapping, or an empty file. Scalars, invalid YAML/JSON, and arrays with non-mapping entries produce diagnostics.

Git files values use the same values.* and .values.* behavior as Git directories. pathParamPrefix applies to all path-related params. For example, pathParamPrefix: myRepo produces .myRepo.path.path in Go templates and myRepo.path in non-Go-template mode.

In PR diff mode, mapped repository URLs use the local --path or --path-orig trees for directory discovery and rendering, even when the ApplicationSet declares revision: master.

List, Matrix, And Merge

List generators support elements and elementsYaml. For non-Go-template ApplicationSets, elements scalar fields must be strings and nested values are flattened to values.<key>. elementsYaml is kept unflattened so matrix-interpolated YAML follows Argo CD’s behavior.

Matrix generators combine exactly two child generators and interpolate the second child from first-child params, including templated elementsYaml.

Merge generators overlay two or more child generators by mergeKeys in base generator order.

Matrix and merge children may use list, Git directories, Git files, fixture-backed provider generators, and nested matrix/merge combinations where the Argo CD v3 nested JSON API permits them.

Provider Fixtures

Provider-backed generators use explicit local fixture files supplied with the repeatable --appset-provider-fixture flag:

drydock get apps --path . --appset-provider-fixture fixtures/appset-providers.yaml
drydock diff apps --path . --path-orig ../base --appset-provider-fixture fixtures/appset-providers.yaml

Fixture files are strict YAML or JSON documents. Unknown fields, duplicate identities, URL-like fixture paths, and malformed files produce appset.provider-fixture-invalid. If fixtures are supplied but no entries match a provider generator, drydock emits appset.provider-no-match. Filters that cannot be evaluated from fixture data fail closed with appset.provider-unsupported-filter.

Fixture Schema

clusters:
  - name: prod-a
    server: https://prod-a.example.invalid
    project: platform
    labels:
      environment: prod
    annotations:
      owner: platform
    values:
      region: home

clusterDecisions:
  - configMapRef: placement-config
    resourceName: placement-a
    labels:
      placement: edge
    matchKey: clusterName
    statusListKey: clusters
    decisions:
      - clusterName: prod-a
        placement: edge
    values:
      tier: edge

scmRepositories:
  - provider: github
    organization: example-org
    repository: example-repo
    repositoryID: repo-123
    branch: main
    sha: abcdef1234567890
    url: https://github.com/example-org/example-repo
    labels:
      - ops
    paths:
      - deploy/app.yaml
    values:
      tier: ops

pullRequests:
  - provider: github
    organization: example-org
    repository: example-repo
    number: 42
    title: Update chart
    branch: renovate/chart
    targetBranch: main
    headSHA: abcdef1234567890
    author: renovate
    labels:
      - dependencies
    values:
      kind: renovate

plugins:
  - configMapRef: generator-plugin
    outputs:
      - environment: prod
        cluster:
          name: prod-a
    values:
      source: fixture

Additional provider-specific fixture fields are available where Argo provider configuration needs scope data that should not alter emitted template params. SCM repositories accept project, region, and tags; pull requests accept project and state. For example, Azure DevOps uses organization plus project, AWS CodeCommit requires explicit region and can evaluate tagFilters from tags, and GitLab pullRequestState is evaluated from state.

Template Parameters

Provider fixtures emit the same stable template parameter names that Argo CD uses for each supported provider family:

For non-Go-template ApplicationSets, nested maps are flattened with dot notation, including metadata.labels.<key>, metadata.annotations.<key>, and values.<key>.

For Go-template ApplicationSets, nested values remain available as maps or arrays, such as .metadata.labels, .metadata.annotations, .labels, and .values.