apache/druid · error · IAE

A local input source requires one property of %s or %s

Error message

A local input source requires one property of %s or %s

What it means

LocalInputSourceDefn.validate requires a local input source to specify at least one of baseDir or files. Without either, Druid has nothing to read. Thrown as IllegalArgumentException during table validation.

Source

Thrown at server/src/main/java/org/apache/druid/catalog/model/table/LocalInputSourceDefn.java:88

    return LocalInputSource.TYPE_KEY;
  }

  @Override
  protected Class<? extends InputSource> inputSourceClass()
  {
    return LocalInputSource.class;
  }

  @Override
  public void validate(ResolvedExternalTable table)
  {
    final Map<String, Object> sourceMap = new HashMap<>(table.inputSourceMap);
    final boolean hasBaseDir = sourceMap.containsKey(BASE_DIR_FIELD);
    final boolean hasFiles = !CollectionUtils.isNullOrEmpty(CatalogUtils.safeGet(sourceMap, FILES_FIELD, List.class));
    final boolean hasFilter = !Strings.isNullOrEmpty(CatalogUtils.getString(sourceMap, FILTER_FIELD));

    if (!hasBaseDir && !hasFiles) {
      throw new IAE(
          "A local input source requires one property of %s or %s",
          BASE_DIR_FIELD,
          FILES_FIELD
      );
    }
    if (!hasBaseDir && hasFilter) {
      throw new IAE(
          "If a local input source sets property %s, it must also set property %s",
          FILTER_FIELD,
          BASE_DIR_FIELD
      );
    }
    if (hasBaseDir && hasFiles) {
      throw new IAE(
          "A local input source accepts only one of %s or %s",
          BASE_DIR_FIELD,
          FILES_FIELD
      );

View on GitHub (pinned to 9b90983fd2)

Solutions

1. Set the baseDir property to the directory containing the files
2. Or provide a non-empty files list of explicit paths
3. Re-run validation after adding one of the two properties

Example fix

// before
{"type":"local","filter":"*.csv"}
// after
{"type":"local","baseDir":"/data/incoming","filter":"*.csv"}

Map<String,Object> src = table.getInputSourceMap();
if (!src.containsKey("baseDir")
    && (src.get("files") == null || ((List<?>) src.get("files")).isEmpty())) {
  throw new IllegalArgumentException("local source needs baseDir or files");
}

try { defn.validate(table); } catch (IAE e) { if (e.getMessage().contains("requires one property")) { /* set baseDir or files */ } else { throw e; } }

When it happens

Trigger: Validating a local ResolvedExternalTable whose inputSourceMap contains neither the baseDir field nor a non-empty files list.

Common situations: Local source config created programmatically with neither property set; switching from another source type and deleting paths without adding new ones; partial edits to the source JSON.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• An inline input source must provide a format.
• An inline input source must provide one or more columns
• If a local input source sets property %s, it must also set p
• A local input source accepts only one of %s or %s
• '%s' must be a string or an array of strings

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/7006ec7a83a6baac. Report an issue: GitHub.