crowdsecurity/crowdsec · error

empty %s DSN

Error message

empty %s DSN

What it means

The docker DSN must name a container: its host part is taken as container name/ID. If parsedURL.Host is empty (e.g. just `docker://`), configuration fails with this error because there is no container to attach logs from.

Source

Thrown at pkg/acquisition/modules/docker/config.go:235

	d.runningServiceState = tracker.NewTracker[*ContainerConfig]()
	d.Config.Mode = configuration.CAT_MODE
	d.logger = logger
	d.Config.Labels = labels

	opts := []client.Opt{
		client.FromEnv,
	}

	d.containerLogsOptions = &client.ContainerLogsOptions{
		ShowStdout: d.Config.FollowStdout,
		ShowStderr: d.Config.FollowStdErr,
		Follow:     false,
	}

	containerNameOrID := parsedURL.Host

	if containerNameOrID == "" {
		return fmt.Errorf("empty %s DSN", d.GetName()+"://")
	}

	d.Config.ContainerName = append(d.Config.ContainerName, containerNameOrID)
	// we add it as an ID also so user can provide docker name or docker ID
	d.Config.ContainerID = append(d.Config.ContainerID, containerNameOrID)

	parameters := parsedURL.Query()

	for k, v := range parameters {
		switch k {
		case "log_level":
			if len(v) != 1 {
				return errors.New("only one 'log_level' parameters is required, not many")
			}
			lvl, err := log.ParseLevel(v[0])
			if err != nil {
				return fmt.Errorf("unknown level %s: %w", v[0], err)
			}

View on GitHub (pinned to 909b515798)

Solutions

1. Add the container name or ID after the scheme: docker://mycontainer.
2. If the name comes from a variable, verify it is set/non-empty at config render time.
3. Alternatively configure via YAML with container_name/container_id lists instead of a DSN.

Example fix

// before
log_path: 'docker://'
// after
log_path: 'docker://nginx-proxy'

u, _ := url.Parse(dsn)
if u != nil && u.Host == "" {
    return errors.New("docker DSN requires a container name or ID: docker://<name>")
}

When it happens

Trigger: ConfigureByDSN called with a DSN like `docker://` or `docker://?follow_stdout=true` where the host (container name or ID) is missing.

Common situations: acquis.yaml entry `log_path: docker://` with container name forgotten; templated config where the variable expanded to empty; reading container name from an unset env var.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• empty journalctl:// DSN
• empty loki host
• while parsing DockerAcquisition configuration: %s
• unsupported mode %s for docker datasource
• container_name_regexp: %w

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/70ee2c733cac0e8a. Report an issue: GitHub.