message for '%s' contains bad data format: missing blocklist

Error message

message for '%s' contains bad data format: missing blocklist name

What it means

ManagementCmd processes management commands received over the PAPI websocket from CrowdSec Central API. For a 'blocklist_unsubscribe' command the payload must contain a non-empty 'name' field identifying the blocklist to unsubscribe from. This error is thrown when the JSON payload unmarshals successfully into blocklistUnsubscribe but its Name field is empty, meaning the central API sent a malformed/incomplete message.

Source

Thrown at pkg/apiserver/papi_cmd.go:208

		p.Logger.Infof("Ignoring management command from PAPI in sync mode")
		return nil
	}

	switch message.Header.OperationCmd {
	case "blocklist_unsubscribe":
		data, err := json.Marshal(message.Data)
		if err != nil {
			return err
		}

		unsubscribeMsg := blocklistUnsubscribe{}

		if err := json.Unmarshal(data, &unsubscribeMsg); err != nil {
			return fmt.Errorf("message for '%s' contains bad data format: %w", message.Header.OperationType, err)
		}

		if unsubscribeMsg.Name == "" {
			return fmt.Errorf("message for '%s' contains bad data format: missing blocklist name", message.Header.OperationType)
		}

		p.Logger.Infof("Received blocklist_unsubscribe command from PAPI, unsubscribing from blocklist %s", unsubscribeMsg.Name)

		filter := make(map[string][]string)
		filter["origin"] = []string{types.ListOrigin}
		filter["scenario"] = []string{unsubscribeMsg.Name}

		_, deletedDecisions, err := p.DBClient.ExpireDecisionsWithFilter(ctx, filter)
		if err != nil {
			return fmt.Errorf("unable to expire decisions for list %s : %w", unsubscribeMsg.Name, err)
		}

		p.Logger.Infof("deleted %d decisions for list %s", len(deletedDecisions), unsubscribeMsg.Name)
	case "reauth":
		p.Logger.Infof("Received reauth command from PAPI, resetting token")
		p.apiClient.GetClient().Transport.(*apiclient.JWTTransport).ResetToken()
	case "force_pull":

View on GitHub (pinned to 909b515798)

Solutions

Check the crowdsec logs for the operation_type in the error to identify which blocklist unsubscribe command was malformed, then inspect the central console for the affected blocklist
Update crowdsec to the latest version so payload handling matches the current central API schema
If it persists, report the malformed payload to CrowdSec (the sender side constructs the message); as a workaround the command is simply rejected and processing continues
Verify no intermediary (proxy, custom integration) rewrites or truncates PAPI websocket messages

Example fix

// before: payload {"operation_cmd":"blocklist_unsubscribe","data":{}}
// after: include the required field
// {"operation_cmd":"blocklist_unsubscribe","data":{"name":"my-blocklist"}}

Defensive patterns

Strategy: validation

Validate before calling

msg, ok := message.Data.(map[string]interface{})
name, ok2 := msg["name"].(string)
if !ok || !ok2 || name == "" {
    return fmt.Errorf("blocklist_unsubscribe payload missing 'name'")
}

Type guard

func validBlocklistUnsubscribe(d map[string]interface{}) bool {
    n, ok := d["name"].(string)
    return ok && n != ""
}

Try / catch

if err := ManagementCmd(ctx, msg, p, false); err != nil {
    if strings.Contains(err.Error(), "missing blocklist name") {
        log.Warnf("skipping malformed PAPI command: %v", err)
        return nil
    }
    return err
}

Prevention

Keep crowdsec and the enrolled console in sync on versions
Do not modify or filter PAPI websocket payloads in proxies
Monitor logs for repeated 'bad data format' messages indicating a sender-side bug

When it happens

Trigger: A blocklist_unsubscribe PAPI message arrives whose JSON data lacks the 'name' key or has it set to "" — e.g. the upstream central API emits an empty placeholder message or a schema change drops the name field.

Common situations: Central API (CAPI) pushing commands with partial payloads; proxy or middleware stripping fields from the websocket message; version mismatch between the console/central API and the local crowdsec agent where the payload shape changed.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/8e6b7b5a3c69bd25. Report an issue: GitHub.