slimtoolkit/slim · error

invalid publish-port: %s

Error message

invalid publish-port: %s

What it means

ParsePortBindings returns 'invalid publish-port: %s' when a publish-port value does not match any accepted hostIP:hostPort:containerPort shape. The parser switches on the number of ':'-separated parts and the default branch rejects values with an unexpected structure. Valid forms are like '80', '8080:80', '127.0.0.1:8080:80' (with optional protocol suffix).

Source

Thrown at pkg/app/master/command/clifvparser.go:123

				portKey = parts[1]
			} else {
				portKey = fmt.Sprintf("%s/tcp", parts[1])
			}
		case 3:
			hostIP = parts[0]
			if len(parts[1]) > 0 {
				hostPort = parts[1]
			} else {
				hostPort = parts[2]
			}

			if strings.Contains(parts[2], "/") {
				portKey = parts[2]
			} else {
				portKey = fmt.Sprintf("%s/tcp", parts[2])
			}
		default:
			return nil, fmt.Errorf("invalid publish-port: %s", raw)
		}

		portBindings[docker.Port(portKey)] = []docker.PortBinding{{
			HostIP:   hostIP,
			HostPort: hostPort,
		}}
	}

	return portBindings, nil
}

func IsOneSpace(value string) bool {
	if len(value) > 0 && utf8.RuneCountInString(value) == 1 {
		r, _ := utf8.DecodeRuneInString(value)
		if r != utf8.RuneError && unicode.IsSpace(r) {
			return true
		}
	}

View on GitHub (pinned to 81940d17fa)

Solutions

1. Use one of the supported forms: 'containerPort', 'host:container', or 'ip:host:container'.
2. Wrap IPv6 host addresses in brackets, e.g. '[::1]:8080:80', so colon splitting stays correct.
3. Remove duplicate or extra segments (max three colon-separated parts).
4. Echo the offending raw value against docker run -p documentation to spot the deviation.

Example fix

// before
publish := []string{"8080:80:80:extra"}
// after
publish := []string{"8080:80"}

parts := strings.Split(raw, ":")
switch len(parts) {
case 1, 2, 3:
    for _, p := range parts {
        if strings.TrimSpace(p) == "" {
            return fmt.Errorf("empty segment in publish-port %q", raw)
        }
    }
default:
    return fmt.Errorf("publish-port %q: expected at most 3 colon-separated parts", raw)
}

bindings, err := command.ParsePortBindings(values)
if err != nil {
    if strings.Contains(err.Error(), "invalid publish-port") {
        return fmt.Errorf("supported forms: port | host:port | ip:host:port: %w", err)
    }
    return err
}

When it happens

Trigger: Calling ParsePortBindings (from CommandFlagValues or inline parsers) with values like 'tcp://80', '80:80:80:80', empty segments, or other malformed publish specs.

Common situations: Typos with extra colons; IPv6 addresses with unbracketed colons confusing the splitter; users pasting full docker run -p syntax variants the slim parser does not support.

Related errors

• invalid EXPOSE format: %s
• invalid port range in EXPOSE: %s / error: %s
• slim: error => missing comms ports
• invalid context directory
• no service image

AI-assisted analysis of slimtoolkit/slim@81940d17fa (2026-08-31). Data as JSON: /api/errors/dbc3cf6c8842ad0e. Report an issue: GitHub.