dagger/dagger · error

failed to call sdk module codegen: %w

Error message

failed to call sdk module codegen: %w

What it means

Dagger wraps any error returned by the dagql Select call that invokes the SDK module's own `codegen` function (e.g. the Go/Python/TypeScript SDK runtime). The wrapped error contains the SDK runtime's own failure — typically a crash, compilation error, or unimplemented function inside the SDK runtime container.

Source

Thrown at core/sdk/module_code_generator.go:64

		return nil, fmt.Errorf("failed to get schema introspection json ID during %s module sdk codegen: %w", sdk.mod.mod.Self().Name(), err)
	}

	var inst dagql.Result[*core.GeneratedCode]
	err = dag.Select(ctx, sdkInst.sdk, &inst, dagql.Selector{
		Field: "codegen",
		Args: []dagql.NamedInput{
			{
				Name:  "modSource",
				Value: dagql.NewID[*core.ModuleSource](sourceID),
			},
			{
				Name:  "introspectionJson",
				Value: dagql.NewID[*core.File](schemaJSONFileID),
			},
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to call sdk module codegen: %w", err)
	}
	return inst.Self(), nil
}

View on GitHub (pinned to 82ba2681db)

Solutions

1. Read the wrapped inner error for the SDK runtime's actual failure message
2. Verify the SDK runtime image can be pulled (network/registry access)
3. Ensure your module's dagger.json sdk field matches a supported SDK version
4. Run `dagger develop` after fixing to regenerate bindings

Example fix

// before: dagger.json
{"sdk": "python"}
// after: pin a concrete supported version
{"sdk": "python"}  // ensure engine supports this SDK; update engine if not

// shell: ensure registry/network reachability for SDK runtime image
dagger query <<'EOF' || echo 'check engine connectivity'
{version}
EOF

// Go client
_, err := src.GeneratedCode(ctx)
if err != nil {
    var pe *connect.PostError // or inspect message
    log.Printf("SDK runtime codegen failed: %v — inspect inner SDK error", err)
    return err
}

When it happens

Trigger: Calling Codegen where the SDK runtime module's `codegen` field errors: the runtime image cannot be pulled, the generated code fails to compile inside the runtime, or the runtime returns a user-facing error.

Common situations: No network access to pull the SDK runtime image; incompatible module source layout for the SDK version; template files in the SDK failing to render; codegen script in the runtime failing.

Related errors

• unknown type %q
• enum types must be named
• failed to find decl for object %s: %w
• failed to find decl for named type %s: %w
• failed to find decl for method %s: %w

AI-assisted analysis of dagger/dagger@82ba2681db (2026-09-05). Data as JSON: /api/errors/92611051d3eb998a. Report an issue: GitHub.