apache/pulsar · error · IllegalArgumentException

Could not validate sink config:

Error message

Could not validate sink config: 

What it means

Thrown by the one-arg validateSinkConfig when converting the sink's configs map to the connector config class or validating it fails with IllegalArgumentException; the original message is prefixed with 'Could not validate sink config: '. It means the user-supplied configs do not conform to the connector's config class schema.

Source

Thrown at pulsar-functions/utils/src/main/java/org/apache/pulsar/functions/utils/SinkConfigUtils.java:765

            if (defn != null && defn.getSinkConfigClass() != null) {
                Class<?> configClass = Class.forName(defn.getSinkConfigClass(), true, sinkFunction.getClassLoader());
                validateSinkConfig(sinkConfig, configClass);
            }
        } catch (ClassNotFoundException e) {
            throw new IllegalArgumentException("Could not find sink config class", e);
        }
    }

    public static void validateSinkConfig(SinkConfig sinkConfig, Class<?> configClass) {
        try {
            Object configObject =
                    ObjectMapperFactory.getMapper().getObjectMapper()
                            .convertValue(sinkConfig.getConfigs(), configClass);
            if (configObject != null) {
                ConfigValidation.validateConfig(configObject);
            }
        } catch (IllegalArgumentException e) {
            throw new IllegalArgumentException("Could not validate sink config: " + e.getMessage());
        }
    }
}

View on GitHub (pinned to 820761864e)

Solutions

1. Read the wrapped message after the prefix to see the exact field that failed
2. Fix the configs map in the sink config so every required field of the connector config class is present with the correct type
3. Consult the connector's config class (sinkConfigClass) for the expected field names and types

Example fix

// before
sinkConfig.setConfigs(Map.of("bootstrapServer", "localhost:9092")); // missing required 'topic'
// after
sinkConfig.setConfigs(Map.of(
    "bootstrapServer", "localhost:9092",
    "topic", "my-topic"));

// validate configs against the connector config class before submitting
Object cfgObj = new ObjectMapper().convertValue(sinkConfig.getConfigs(), MyConnectorSinkConfig.class);
ConfigValidation.validateConfig(cfgObj);

try {
    admin.sinks().updateSink(tenant, namespace, cfg, null);
} catch (IllegalArgumentException e) {
    if (e.getMessage().startsWith("Could not validate sink config:")) { /* log cause, fix configs map */ }
    else throw e;
}

When it happens

Trigger: SinkConfig.getConfigs() contains keys/types that cannot be mapped to the connector's config class fields (Jackson convertValue fails) or ConfigValidation.validateConfig rejects a missing/invalid required field.

Common situations: Missing required config keys (e.g. missing 'topics' or 'bootstrapServer'); wrong value type (string where number expected) in the sink config YAML; config key renamed between connector versions.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Topic %s has an incorrect schema Info
• Only one of schemaType or serdeClassName should be set in in
• Only one of outputSchemaType or outputSerdeClassName should
• Sink Names differ
• Subscription Name cannot be altered

AI-assisted analysis of apache/pulsar@820761864e (2026-09-06). Data as JSON: /api/errors/6236b423200c646d. Report an issue: GitHub.