amir20/dozzle · error

error finding container

Error message

error finding container %s: %v

What it means

After the host~id split succeeds, downloadLogs calls hostService.FindContainer(host, id, userLabels). If the host cannot be reached or no container with that id exists on it, a 400 containing "error finding container %s: %v" is returned with the underlying error appended.

Solutions

  1. Refresh the container list and use the current container id from the API.
  2. Verify the host segment matches an available host id/name.
  3. Check host connectivity (remote agent reachable) before retrying.

Example fix

// before
const stale = JSON.parse(localStorage.getItem('lastContainer'))
download(stale.host + '~' + stale.id)
// after
const containers = await fetch('/api/containers.json').then(r => r.json())
const current = containers.find(c => c.name === stale.name)
if (current) download(current.host + '~' + current.id)
Defensive patterns

Strategy: try-catch

Try / catch

try {
  const res = await fetch(url);
  if (res.status === 400) {
    const msg = await res.text();
    if (msg.startsWith('error finding container')) await refreshContainersAndRetry();
  }
} catch (e) { /* network failure */ }

Prevention

When it happens

Trigger: GET download with host~id where the host is unknown/disconnected or the container id does not exist (e.g. container was recreated and its id changed).

Common situations: Container recreated after image upgrade so the stored id is stale; agent host offline or removed from the host list; typos in host names when crafting URLs by hand; k8s pod restarts producing new ids.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

AI-assisted analysis of amir20/dozzle@d9463cbe21 (2026-09-07). Data as JSON: /api/errors/c8e146917d4a7349. Report an issue: GitHub.

Appendix: source

Thrown at internal/web/download.go:104

		id               string
		containerService *container_support.ContainerService
	}
	containers := make([]containerInfo, 0, len(hostIds))

	for _, hostId := range hostIds {
		parts := strings.Split(hostId, "~")
		if len(parts) != 2 {
			log.Error().Msgf("invalid host id: %s", hostId)
			http.Error(w, fmt.Sprintf("invalid host id: %s", hostId), http.StatusBadRequest)
			return
		}

		host := parts[0]
		id := parts[1]
		containerService, err := h.hostService.FindContainer(host, id, userLabels)
		if err != nil {
			log.Error().Err(err).Msgf("error finding container %s", id)
			http.Error(w, fmt.Sprintf("error finding container %s: %v", id, err), http.StatusBadRequest)
			return
		}

		containers = append(containers, containerInfo{
			hostId:           hostId,
			host:             host,
			id:               id,
			containerService: containerService,
		})
	}

	// Determine zip filename from optional name param or default
	zipName := "container-logs"
	if name := r.URL.Query().Get("name"); name != "" {
		// Sanitize: keep only alphanumeric, hyphens, underscores, dots
		sanitized := strings.Map(func(r rune) rune {
			if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '-' || r == '_' || r == '.' {
				return r

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