nektos/act · error

invalid publish opts format (should be name=value but got '%

Error message

invalid publish opts format (should be name=value but got '%s')

What it means

convertToStandardNotation converts Docker's long publish syntax (-p published=8080,target=80,protocol=tcp) into the standard host:container/proto form. Each comma-separated parameter must contain '=' with a non-empty key; a fragment like '8080' or '=tcp' (empty key) fails with this error before the container is created.

Source

Thrown at pkg/container/docker_cli.go:915

	if ep.MacAddress != "" {
		ma, err := net.ParseMAC(strings.TrimSpace(ep.MacAddress))
		if err != nil {
			return nil, fmt.Errorf("%s is not a valid mac address", ep.MacAddress)
		}
		epConfig.MacAddress = network.HardwareAddr(ma)
	}
	return epConfig, nil
}

func convertToStandardNotation(ports []string) ([]string, error) {
	optsList := []string{}
	for _, publish := range ports {
		if strings.Contains(publish, "=") {
			params := map[string]string{"protocol": "tcp"}
			for param := range strings.SplitSeq(publish, ",") {
				k, v, ok := strings.Cut(param, "=")
				if !ok || k == "" {
					return optsList, fmt.Errorf("invalid publish opts format (should be name=value but got '%s')", param)
				}
				params[k] = v
			}
			optsList = append(optsList, fmt.Sprintf("%s:%s/%s", params["published"], params["target"], params["protocol"]))
		} else {
			optsList = append(optsList, publish)
		}
	}
	return optsList, nil
}

func parseLoggingOpts(loggingDriver string, loggingOpts []string) (map[string]string, error) {
	loggingOptsMap := opts.ConvertKVStringsToMap(loggingOpts)
	if loggingDriver == "none" && len(loggingOpts) > 0 {
		return map[string]string{}, fmt.Errorf("invalid logging opts for driver %s", loggingDriver)
	}
	return loggingOptsMap, nil
}

View on GitHub (pinned to 4f41128141)

Solutions

1. Use the standard form -p 8080:80/tcp, or the fully-formed long syntax -p published=8080,target=80,protocol=tcp
2. Remove stray '=' characters from port values and trailing commas
3. Check YAML folded scalars for accidental line-join artifacts

Example fix

# before
options: -p localhost:8080=80

# after
options: -p 8080:80

for _, p := range ports {
    if strings.Contains(p, "=") {
        for _, param := range strings.Split(p, ",") {
            k, _, ok := strings.Cut(param, "=")
            if !ok || k == "" {
                return fmt.Errorf("bad long-syntax publish %q", p)
            }
        }
    }
}

When it happens

Trigger: Passing -p/--publish with '=' present in the value (which routes it to the long-syntax parser) but a malformed list: '-p 8080=,target=80', '-p =8080,target=80', or a stray trailing comma producing an empty-ish param. Note any '=' anywhere in the -p value selects the long format, so 'localhost:8080=80' also trips it.

Common situations: Copy-pasting URL-ish or key=value strings into -p; mixing legacy ':=' style; trailing commas in YAML folded option strings; assuming act accepts docker-compose port mappings.

Related errors

• invalid range format for --expose: %w
• --cgroupns: invalid CGROUP mode
• parse %q: %w
• %s is not a valid mac address
• invalid value: %d. Valid memory swappiness range is 0-100

AI-assisted analysis of nektos/act@4f41128141 (2026-08-15). Data as JSON: /api/errors/67c2ee4fe626e841. Report an issue: GitHub.