What causes "service_name_regexp: %w" in crowdsecurity/crowdsec?

Fix the pattern so it compiles as a Go/RE2 regex.

service_name_regexp: %w

Error message

service_name_regexp: %w

What it means

Same mechanism as container_id_regexp but for the `service_name_regexp` list: each entry is compiled with regexp.Compile during UnmarshalConfig, and an invalid pattern aborts configuration with this wrapped error. It indicates a syntactically invalid RE2 regular expression in the service_name_regexp config.

Source

Thrown at pkg/acquisition/modules/docker/config.go:113

			return fmt.Errorf("container_name_regexp: %w", err)
		}

		d.compiledContainerName = append(d.compiledContainerName, compiled)
	}

	for _, cont := range d.Config.ContainerIDRegexp {
		compiled, err := regexp.Compile(cont)
		if err != nil {
			return fmt.Errorf("container_id_regexp: %w", err)
		}

		d.compiledContainerID = append(d.compiledContainerID, compiled)
	}

	for _, svc := range d.Config.ServiceNameRegexp {
		compiled, err := regexp.Compile(svc)
		if err != nil {
			return fmt.Errorf("service_name_regexp: %w", err)
		}

		d.compiledServiceName = append(d.compiledServiceName, compiled)
	}

	for _, svc := range d.Config.ServiceIDRegexp {
		compiled, err := regexp.Compile(svc)
		if err != nil {
			return fmt.Errorf("service_id_regexp: %w", err)
		}

		d.compiledServiceID = append(d.compiledServiceID, compiled)
	}

	if d.Config.Since == "" {
		d.Config.Since = time.Now().UTC().Format(time.RFC3339)
	}

View on GitHub (pinned to 909b515798)

Solutions

Fix the pattern so it compiles as a Go/RE2 regex.
Replace PCRE-only features (lookarounds, named backrefs) with RE2-compatible constructs.
Test the pattern standalone with regexp.Compile before deploying.
If no regex is needed, use the plain `service_name` list instead.

Example fix

// before
service_name_regexp:
  - "my-svc(?<env>prod)"  // Go has no named backref syntax like PCRE here
// after
service_name_regexp:
  - "my-svc-(prod|staging)"

Defensive patterns

Strategy: validation

Validate before calling

for _, re := range cfg.ServiceNameRegexp {
    if _, err := regexp.Compile(re); err != nil {
        return fmt.Errorf("invalid service_name_regexp %q: %w", re, err)
    }
}

Prevention

Validate patterns against Go's RE2 engine, not your shell's grep flavor.
Keep service regexes simple (prefix/suffix matching) to reduce syntax risk.
Check YAML quoting — patterns with special chars should be single-quoted.

When it happens

Trigger: UnmarshalConfig iterating d.Config.ServiceNameRegexp and encountering a string regexp.Compile rejects (unbalanced parentheses, dangling `+`/`*`, invalid character class, RE2-unsupported syntax).

Common situations: Docker Swarm service filtering configured with a typo'd or PCRE-flavored regex; copy-pasted regex from a tutorial with language-specific syntax; accidentally quoting issues in YAML producing a mangled pattern.

Related errors

AI-assisted analysis of crowdsecurity/crowdsec@909b515798 (2026-09-06). Data as JSON: /api/errors/5716d07d7b661e9b. Report an issue: GitHub.