alibaba/nacos · warning · IllegalArgumentException

Param 'resourcePattern' is illegal, resourcePattern is blank

Error message

Param 'resourcePattern' is illegal, resourcePattern is blank

What it means

Thrown by FuzzyGroupKeyPattern.generatePattern when resourcePattern (the dataId/service-name pattern) is blank (null, empty, or whitespace only). This is the first validation in the method; groupPattern and fixNamespace are checked next. The result pattern is fixNamespace>>groupPattern>>resourcePattern, so a blank resourcePattern makes the key meaningless.

Source

Thrown at common/src/main/java/com/alibaba/nacos/common/utils/FuzzyGroupKeyPattern.java:54

 * @author stone-98
 * @date 2024/3/14
 */
public class FuzzyGroupKeyPattern {
    
    /**
     * Generates a fuzzy listen group key pattern based on the given dataId pattern, group, and optional tenant. pattern
     * result as: fixNamespace>>groupPattern>>dataIdPattern
     *
     * @param resourcePattern The pattern for matching dataIds or service names.
     * @param groupPattern    The groupPattern associated with the groups.
     * @param fixNamespace    (Optional) The tenant associated with the dataIds (can be null or empty).
     * @return A unique group key pattern for fuzzy listen.
     * @throws IllegalArgumentException If the dataId pattern or group is blank.
     */
    public static String generatePattern(final String resourcePattern, final String groupPattern,
        String fixNamespace) {
        if (StringUtils.isBlank(resourcePattern)) {
            throw new IllegalArgumentException(
                "Param 'resourcePattern' is illegal, resourcePattern is blank");
        }
        if (StringUtils.isBlank(groupPattern)) {
            throw new IllegalArgumentException("Param 'groupPattern' is illegal, group is blank");
        }
        if (StringUtils.isBlank(fixNamespace)) {
            fixNamespace = DEFAULT_NAMESPACE_ID;
        }
        StringBuilder sb = new StringBuilder();
        sb.append(fixNamespace);
        sb.append(FUZZY_WATCH_PATTERN_SPLITTER);
        sb.append(groupPattern);
        sb.append(FUZZY_WATCH_PATTERN_SPLITTER);
        sb.append(resourcePattern);
        return sb.toString().intern();
    }
    
    /**

View on GitHub (pinned to 9b989acdf1)

Solutions

  1. Validate the resourcePattern is non-blank at the API/UI boundary before calling fuzzy subscribe.
  2. Require a wildcard pattern (e.g., 'prefix-*') — fuzzy listen expects a pattern, not an empty string.
  3. Trim and reject blank input in the request form validator.

Example fix

// before
String key = FuzzyGroupKeyPattern.generatePattern(dataIdPattern, group, namespace);

// after
if (StringUtils.isBlank(dataIdPattern)) {
    throw new IllegalArgumentException("dataIdPattern is required for fuzzy listen");
}
String key = FuzzyGroupKeyPattern.generatePattern(dataIdPattern, group, namespace);
Defensive patterns

Strategy: validation

Validate before calling

if (StringUtils.isBlank(resourcePattern)) {
    throw new IllegalArgumentException("A non-blank resourcePattern is required for fuzzy listen");
}
String key = FuzzyGroupKeyPattern.generatePattern(resourcePattern, groupPattern, fixNamespace);

Prevention

When it happens

Trigger: Registering a fuzzy listen/watch with a blank dataId or service-name pattern. Entry point: fuzzy config listen or fuzzy service watch APIs that ultimately call generatePattern.

Common situations: UI or API caller submitting a fuzzy subscribe with an empty pattern field; a default that resolved to null; whitespace-only input not trimmed upstream.

Related errors

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/8071bef866b036d1. Report an issue: GitHub.