ipfs/kubo · error

'type' field missing or not a string

Error message

'type' field missing or not a string

What it means

AnyDatastoreConfig builds a DatastoreConfig from a JSON-style spec map by first reading params["type"]. If the key is absent or its value does not assert to string, the spec is unusable (the datastore registry is keyed by type name), so the function returns this error instead of guessing.

Source

Thrown at repo/fsrepo/datastores.go:81

	}
}

func AddDatastoreConfigHandler(name string, dsc ConfigFromMap) error {
	_, ok := datastores[name]
	if ok {
		return fmt.Errorf("already have a datastore named %q", name)
	}

	datastores[name] = dsc
	return nil
}

// AnyDatastoreConfig returns a DatastoreConfig from a spec based on
// the "type" parameter.
func AnyDatastoreConfig(params map[string]any) (DatastoreConfig, error) {
	which, ok := params["type"].(string)
	if !ok {
		return nil, fmt.Errorf("'type' field missing or not a string")
	}
	fun, ok := datastores[which]
	if !ok {
		return nil, fmt.Errorf("unknown datastore type: %s", which)
	}
	return fun(params)
}

type mountDatastoreConfig struct {
	mounts []premount
}

type premount struct {
	ds     DatastoreConfig
	prefix ds.Key
}

// MountDatastoreConfig returns a mount DatastoreConfig from a spec.

View on GitHub (pinned to 329838acdf)

Solutions

1. Add a "type" key with the datastore name (e.g. "mounts", "flatfs", "levelds", "measure", "log") to the spec map
2. Print/inspect the spec map and fix JSON parsing so "type" survives as a string, e.g. use json.Unmarshal into map[string]any
3. If the spec came from a migration or tooling, regenerate it with a template that includes "type"

Example fix

// before
spec := map[string]any{"path": "/datastore"}
ds, err := fsrepo.AnyDatastoreConfig(spec) // error
// after
spec := map[string]any{"type": "flatfs", "path": "/datastore"}
ds, err := fsrepo.AnyDatastoreConfig(spec)

func validSpec(params map[string]any) bool {
	t, ok := params["type"].(string)
	return ok && t != ""
}
if !validSpec(spec) { /* fix spec before calling */ }

func hasStringType(params map[string]any) (string, bool) {
	t, ok := params["type"].(string)
	return t, ok
}

ds, err := fsrepo.AnyDatastoreConfig(spec)
if err != nil {
	if strings.Contains(err.Error(), "'type' field missing") {
		// log spec keys and abort init
	}
	return fmt.Errorf("invalid datastore spec %v: %w", spec, err)
}

When it happens

Trigger: Calling AnyDatastoreConfig(params) where params is a map[string]any parsed from a Datastore spec that lacks a "type" key, or where params["type"] is a non-string value (e.g. int, nil, nested map from malformed JSON).

Common situations: Hand-edited or programmatically generated datastore spec in the repo config missing the "type" field; JSON unmarshalled into the wrong shape; a mount entry forgetting its type; config migration or templating tools dropping the field.

Related errors

• creating datastore config for %s: %w
• unknown datastore type: %s
• 'mounts' field is missing or not an array
• expected map for mountpoint
• no 'mountpoint' on mount

AI-assisted analysis of ipfs/kubo@329838acdf (2026-09-03). Data as JSON: /api/errors/5f6df0c717112e1b. Report an issue: GitHub.