apache/beam · error · IllegalArgumentException

Pub/Sub schema type %s is not supported at this time

Error message

Pub/Sub schema type %s is not supported at this time

What it means

PubsubClient.fromPubsubSchema converts a REST (com.google.api.services.pubsub.model) Schema into a Beam Schema. Only types present in schemaTypeToConversionFnMap (AVRO and PROTO) are supported; any other schema type cannot be converted, so an IllegalArgumentException naming the unsupported type is thrown.

Source

Thrown at sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/pubsub/PubsubClient.java:568

  /** Create {@link com.google.api.services.pubsub.model.Schema} from Schema definition content. */
  public abstract void createSchema(
      SchemaPath schemaPath, String schemaContent, com.google.pubsub.v1.Schema.Type type)
      throws IOException;

  /** Delete {@link SchemaPath}. */
  public abstract void deleteSchema(SchemaPath schemaPath) throws IOException;

  /** Return {@link SchemaPath} from {@link TopicPath} if exists. */
  public abstract @Nullable SchemaPath getSchemaPath(TopicPath topicPath) throws IOException;

  /** Return a Beam {@link Schema} from the Pub/Sub schema resource, if exists. */
  public abstract Schema getSchema(SchemaPath schemaPath) throws IOException;

  /** Convert a {@link com.google.api.services.pubsub.model.Schema} to a Beam {@link Schema}. */
  static Schema fromPubsubSchema(com.google.api.services.pubsub.model.Schema pubsubSchema) {
    if (!schemaTypeToConversionFnMap.containsKey(pubsubSchema.getType())) {
      throw new IllegalArgumentException(
          String.format(
              "Pub/Sub schema type %s is not supported at this time", pubsubSchema.getType()));
    }
    SerializableFunction<String, Schema> definitionToSchemaFn =
        checkStateNotNull(schemaTypeToConversionFnMap.get(pubsubSchema.getType()));
    String definition =
        checkNotNull(pubsubSchema.getDefinition(), "Pub/Sub schema definition is null");
    return definitionToSchemaFn.apply(definition);
  }

  /** Convert a {@link com.google.pubsub.v1.Schema} to a Beam {@link Schema}. */
  static Schema fromPubsubSchema(com.google.pubsub.v1.Schema pubsubSchema) {
    String typeName = pubsubSchema.getType().name();
    if (!schemaTypeToConversionFnMap.containsKey(typeName)) {
      throw new IllegalArgumentException(
          String.format("Pub/Sub schema type %s is not supported at this time", typeName));
    }
    SerializableFunction<String, Schema> definitionToSchemaFn =

View on GitHub (pinned to 12126d8942)

Solutions

Change the topic's schema to AVRO (or a supported PROTO type)
Upgrade Beam to a version whose schemaTypeToConversionFnMap includes the schema type
Read without schema resolution (plain PubsubIO.read) and parse bytes manually
Delete/recreate the schema resource attached to the topic with a supported type

Example fix

// before
gcloud pubsub schemas create my-schema --type=unsupported-type --definition=file.json
// after
gcloud pubsub schemas create my-schema --type=AVRO --definition=file.avsc

Defensive patterns

Strategy: try-catch

Validate before calling

if (!"AVRO".equals(pubsubSchema.getType()) && !"PROTOCOL_BUFFER".equals(pubsubSchema.getType())) {
  throw new IllegalArgumentException("Unsupported Pub/Sub schema type: " + pubsubSchema.getType());
}

Try / catch

try { Schema s = PubsubClient.fromPubsubSchema(restSchema); } catch (IllegalArgumentException e) { /* use non-schema read path */ }

Prevention

Use AVRO schemas on topics read with schema-aware PubsubIO
Keep Beam up to date with supported schema types
Confirm schema type before wiring schema-aware reads
Avoid exotic/custom schema types on Beam-consumed topics

When it happens

Trigger: Reading from a Pub/Sub topic with a schema whose type is not in schemaTypeToConversionFnMap, e.g. a schema of type other than AVRO/PROTO, when PubsubIO resolves the topic schema (readWithSchema / schema-aware reads).

Common situations: Topic schema created with a newer/experimental Pub/Sub schema type; schema changed on the topic after the pipeline was written; using a protocol-buffer schema variant that the Beam version in use does not map.

Related errors

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/6a33a50bb3ec53a4. Report an issue: GitHub.