apache/dolphinscheduler · error · ServiceException

limit must be -1 or greater than 0

Error message

limit must be -1 or greater than 0

What it means

FetchFileContentDtoValidator.validate throws this ServiceException when limit is neither -1 (meaning 'return all remaining lines') nor a positive number, i.e. it is 0 or any negative value other than -1.

Source

Thrown at dolphinscheduler-api/src/main/java/org/apache/dolphinscheduler/api/validator/resource/FetchFileContentDtoValidator.java:41

import org.apache.dolphinscheduler.dao.repository.TenantDao;
import org.apache.dolphinscheduler.plugin.storage.api.StorageOperator;

import org.springframework.stereotype.Component;

@Component
public class FetchFileContentDtoValidator extends AbstractResourceValidator<FetchFileContentDto> {

    public FetchFileContentDtoValidator(StorageOperator storageOperator, TenantDao tenantDao) {
        super(storageOperator, tenantDao);
    }

    @Override
    public void validate(FetchFileContentDto fetchFileContentDto) {
        if (fetchFileContentDto.getSkipLineNum() < 0) {
            throw new ServiceException("skipLineNum must be greater than or equal to 0");
        }
        if (fetchFileContentDto.getLimit() != -1 && fetchFileContentDto.getLimit() <= 0) {
            throw new ServiceException("limit must be -1 or greater than 0");
        }
        String resourceFileAbsolutePath = fetchFileContentDto.getResourceFileAbsolutePath();
        User loginUser = fetchFileContentDto.getLoginUser();

        exceptionResourceAbsolutePathInvalidated(resourceFileAbsolutePath);
        exceptionResourceIsNotFile(resourceFileAbsolutePath);
        exceptionUserNoResourcePermission(loginUser, resourceFileAbsolutePath);
        exceptionFileContentCannotFetch(resourceFileAbsolutePath);
    }
}

View on GitHub (pinned to 02eac45a1b)

Solutions

1. Use limit = -1 to fetch the whole file, or a positive integer for paged reads.
2. Clamp client-side page sizes: ensure pageSize > 0 before building the request.
3. Map any 'unlimited' sentinel in your code to -1 before calling the API.

Example fix

// before
fetchFileContent(loginUser, path, 0, 0); // 0 rejected
// after
fetchFileContent(loginUser, path, 0, -1); // whole file
// or
fetchFileContent(loginUser, path, 0, 100); // first 100 lines

if (limit != -1 && limit <= 0) { throw new IllegalArgumentException("limit must be -1 or > 0"); }

boolean isValidLimit(int limit) { return limit == -1 || limit > 0; }

When it happens

Trigger: Calling the read-file-content API with limit = 0, -2, or other invalid values; only limit == -1 and limit > 0 are accepted.

Common situations: Client using 0 as a sentinel for 'unlimited' instead of -1; broken pagination math yielding 0-sized pages; copy-pasted code from APIs where 0 means unlimited.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

• skipLineNum must be greater than or equal to 0
• The path is not a directory: ${directoryAbsolutePath}
• 10001
• DESCRIPTION_TOO_LONG_ERROR
• ENVIRONMENT_NAME_IS_NULL

AI-assisted analysis of apache/dolphinscheduler@02eac45a1b (2026-09-06). Data as JSON: /api/errors/d3b289134bc41796. Report an issue: GitHub.