apolloconfig/apollo · error · BadRequestException

value too long. length limit

Error message

value too long. length limit:%s

What it means

A BadRequestException (HTTP 400) thrown from ItemService.checkItemValueLength() when an item's value exceeds the configured length limit. The limit is determined by getItemValueLengthLimit(): per-namespace override > per-appId override > global default (DEFAULT_ITEM_VALUE_LENGTH = 20000). For gray-release namespaces (cluster name matching pattern [0-9]{14}-[a-zA-Z0-9]{16}), the limit may be raised to the parent namespace's limit if it is larger.

Solutions

1. Shorten the value to be within the limit, or store large data externally and reference it by URL/key in Apollo.
2. Increase the limit via biz config key 'item.value.length.limit' (minimum 5).
3. Set a per-appId override via 'appid.value.length.limit.override' (JSON: {"appId": limit}) or per-namespace via 'namespace.value.length.limit.override' (JSON: {"namespaceId": limit}).
4. For gray namespaces, ensure the parent namespace has a sufficiently large limit so the gray limit inherits it.

Example fix

// before: storing a huge value directly
item.setValue(hugeCertificatePem); // > 20000 chars -> rejected

// after option 1: reference externally
item.setValue("s3://config-bucket/cert.pem");

// after option 2: increase limit in biz config
// System Settings: item.value.length.limit = 50000

// Check value length against the configured limit before saving
int limit = bizConfig.itemValueLengthLimit(); // default 20000
if (!StringUtils.isEmpty(value) && value.length() > limit) {
    // truncate, externalize, or increase limit before proceeding
    throw new IllegalArgumentException("Value exceeds limit of " + limit);
}
item.setValue(value);
itemService.save(item);

When it happens

Trigger: ItemService.save() or update() is called with a value whose length exceeds the resolved limit. The check fires for non-empty values only. Config keys involved: item.value.length.limit (default 20000), appid.value.length.limit.override (JSON map), namespace.value.length.limit.override (JSON map).

Common situations: Storing a large blob, certificate, or long JSON string as a config value that exceeds 20000 characters; the global limit was lowered via config after large values were already present; a migration importing values that exceed the limit.

Related errors

• key too long. length limit
• The maximum number of items
• type is invalid. type should be in [0, 3].
• AccessKeys count limit exceeded
• Can't rollback namespace

AI-assisted analysis of apolloconfig/apollo@d95fc18d11 (2026-08-14). Data as JSON: /api/errors/838aa8282be33c60. Report an issue: GitHub.

Appendix: source

Thrown at apollo-biz/src/main/java/com/ctrip/framework/apollo/biz/service/ItemService.java:234

    auditService.audit(Item.class.getSimpleName(), managedItem.getId(), Audit.OP.UPDATE,
        managedItem.getDataChangeLastModifiedBy());

    return managedItem;
  }

  private boolean checkItemValueLength(long namespaceId, String value) {
    Namespace currentNamespace = namespaceService.findOne(namespaceId);
    int limit = getItemValueLengthLimit(currentNamespace);
    if (currentNamespace != null) {
      Matcher m = clusterPattern.matcher(currentNamespace.getClusterName());
      boolean isGray = m.matches();
      if (isGray) {
        limit = getGrayNamespaceItemValueLengthLimit(currentNamespace, limit);
      }
    }
    if (!StringUtils.isEmpty(value) && value.length() > limit) {
      throw new BadRequestException("value too long. length limit:" + limit);
    }
    return true;
  }

  private int getGrayNamespaceItemValueLengthLimit(Namespace grayNamespace,
      int grayNamespaceLimit) {
    Namespace parentNamespace = namespaceService.findParentNamespace(grayNamespace);
    if (parentNamespace != null) {
      int parentLimit = getItemValueLengthLimit(parentNamespace);
      if (parentLimit > grayNamespaceLimit) {
        return parentLimit;
      }
    }
    return grayNamespaceLimit;
  }

  private boolean checkItemKeyLength(String key) {
    if (!StringUtils.isEmpty(key) && key.length() > bizConfig.itemKeyLengthLimit()) {

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