apache/hadoop · error · IllegalArgumentException

Unsupported Operation [{0}]

Error message

Unsupported Operation [{0}]

What it means

After op resolves to a valid enum constant, ParametersProvider.get checks the provider's paramsDef map (ParametersProvider.java:80); if the operation has no registered parameter classes it throws IllegalArgumentException("Unsupported Operation [...]") → HTTP 400. The stock HttpFSParametersProvider registers every Operation constant, so in a vanilla server this never fires — it is the signature of a fork or embedded wsrs framework that added an enum constant without a PARAMS_DEF entry.

Source

Thrown at hadoop-hdfs-project/hadoop-hdfs-httpfs/src/main/java/org/apache/hadoop/lib/wsrs/ParametersProvider.java:80

    Map<String, String[]> queryString = request.getParameterMap();
    String str = null;
    if(queryString.containsKey(driverParam)) {
      str = queryString.get(driverParam)[0];
    }
    if (str == null) {
      throw new IllegalArgumentException(
        MessageFormat.format("Missing Operation parameter [{0}]",
                             driverParam));
    }
    Enum op;
    try {
      op = Enum.valueOf(enumClass, StringUtils.toUpperCase(str));
    } catch (IllegalArgumentException ex) {
      throw new IllegalArgumentException(
        MessageFormat.format("Invalid Operation [{0}]", str));
    }
    if (!paramsDef.containsKey(op)) {
      throw new IllegalArgumentException(
        MessageFormat.format("Unsupported Operation [{0}]", op));
    }
    for (Class<Param<?>> paramClass : paramsDef.get(op)) {
      Param<?> param = newParam(paramClass);
      List<Param<?>> paramList = Lists.newArrayList();
      String[] ps = queryString.get(param.getName());
      if (ps != null) {
        for (String p : ps) {
          try {
            param.parseParam(p);
          }
          catch (Exception ex) {
            throw new IllegalArgumentException(ex.toString(), ex);
          }
          paramList.add(param);
          param = newParam(paramClass);
        }
      } else {

View on GitHub (pinned to 2add963021)

Solutions

1. Register every operation in the provider's static init: PARAMS_DEF.put(Operation.YOUROP, new Class[]{ YourParam.class, ... }).
2. If the operation must not be served, remove the enum constant so clients get the clearer 'Invalid Operation' message, or block it at the auth/filter layer.
3. Add a unit test asserting paramsDef.keySet() equals all enum constants.
4. Treat any occurrence as a server wiring bug and fix the provider, not the client.

Example fix

// before
public static final Map<Operation, Class<Param<?>>[]> PARAMS_DEF = new HashMap<>();
static { PARAMS_DEF.put(Operation.GETFILESTATUS, new Class[]{}); }
// Operation.MYOP exists in the enum but is never registered -> 400 Unsupported Operation

// after
static { 
  PARAMS_DEF.put(Operation.GETFILESTATUS, new Class[]{});
  PARAMS_DEF.put(Operation.MYOP, new Class[]{ MyOpParam.class });
}

EnumSet<Op> registered = EnumSet.noneOf(Op.class);
registered.addAll(paramsDef.keySet());
if (!registered.equals(EnumSet.allOf(Op.class))) {
  throw new IllegalStateException("paramsDef missing entries for: " + EnumSet.complementOf(registered));
}

static boolean isRegistered(Enum<?> op, Map<Enum, ?> paramsDef) {
  return paramsDef.containsKey(op);
}

try {
  params = provider.get(request);
} catch (IllegalArgumentException ex) {
  if (ex.getMessage().contains("Unsupported Operation")) {
    LOG.error("provider wiring bug: operation not in paramsDef", ex);
    return serverError();
  }
  throw ex;
}

When it happens

Trigger: Adding Operation.MYOP (or a constant in a custom driver enum passed to your own ParametersProvider) without paramsDef.put(MYOP, new Class[]{...}); the first ?op=MYOP request parses the enum fine but fails the map lookup and throws.

Common situations: Vendored httpfs with custom operations; a PARAMS_DEF entry deleted while the enum constant stayed; copy-paste mistakes when wiring a new provider's static initializer.

Related errors

• Param class [{0}] does not have default constructor
• [{0}] = [{1}] exceeds max len [{2}]
• [{0}] = [{1}] must be "{2}"
• parameter [{0}] = [{1}] must be greater than zero
• parameter [{0}] = [{1}] must be greater than or equals zero

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/63fd013cf34258f0. Report an issue: GitHub.