GoogleContainerTools/skaffold · error

unknown builder for config %+v

Error message

unknown builder for config %+v

What it means

GetBuilder maps the configured build type (docker, ko, bazel, jib, kaniko, custom, etc.) to a builder implementation. This error is returned when the `p.Build` artifact type in the pipeline config matches none of the known builder cases — meaning the default branch of the type switch was reached. It dumps the whole Build config in the message for diagnosis.

Source

Thrown at pkg/skaffold/runner/builder.go:76

			return nil, err
		}
		return builder, nil

	case p.Build.GoogleCloudBuild != nil:
		log.Entry(context.TODO()).Debug("Using builder: google cloud")
		builder := gcb.NewBuilder(bCtx, p.Build.GoogleCloudBuild)
		return builder, nil

	case p.Build.Cluster != nil:
		log.Entry(context.TODO()).Debug("Using builder: cluster")
		builder, err := cluster.NewBuilder(bCtx, p.Build.Cluster)
		if err != nil {
			return nil, err
		}
		return builder, err

	default:
		return nil, fmt.Errorf("unknown builder for config %+v", p.Build)
	}
}

type pipelineBuilderWithHooks struct {
	build.PipelineBuilder
	hooksRunner hooks.Runner
}

// PreBuild executes any one-time setup required prior to starting any build on this builder,
// followed by any Build pre-hooks set for the pipeline.
func (b *pipelineBuilderWithHooks) PreBuild(ctx context.Context, out io.Writer) error {
	if err := b.PipelineBuilder.PreBuild(ctx, out); err != nil {
		return err
	}

	if err := b.hooksRunner.RunPreHooks(ctx, out); err != nil {
		return fmt.Errorf("running builder pre-hooks: %w", err)
	}

View on GitHub (pinned to a1189de023)

Solutions

1. Check the `build:` section of skaffold.yaml and set a supported builder (docker, ko, bazel, jib, kaniko, custom, etc.)
2. Upgrade/downgrade Skaffold so it matches the schema version of the config file
3. If constructing config in code/tests, ensure the BuildConfig's artifact type field is populated

Example fix

// before (skaffold.yaml)
build:
  artifacts:
    - image: app
      # no builder specified
// after
build:
  artifacts:
    - image: app
      docker:
        dockerfile: Dockerfile

const supported = ['docker','ko','bazel','jib','kaniko','custom','buildpacks']
if (!supported.includes(pipeline.build.artifactType)) {
  throw new Error(`unsupported builder: ${pipeline.build.artifactType}`)
}

When it happens

Trigger: Calling GetBuilder with a pipeline whose BuildConfig holds an artifact type that no builder implementation registered for — e.g. an empty/unset build type, or a config parsed from a newer skaffold.yaml schema field this version doesn't support.

Common situations: Using a skaffold.yaml built for a newer/older Skaffold version with an unsupported builder; manually constructed config structs in tests with the build type left zero-valued.

Related errors

• image %q context %q is not a directory
• getting target platforms: %w
• bucket name is empty
• INSPECT_PROFILE_NOT_FOUND_ERR
• cannot resolve active Kubernetes context - multiple contexts

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/d2851da1fbed7315. Report an issue: GitHub.