Examples with SamzaSqlInputTransformer org.apache.samza.sql.SamzaSqlInputTransformer used on opensource projects

Example 1 with SamzaSqlInputTransformer

use of org.apache.samza.sql.SamzaSqlInputTransformer in project samza by apache.

the class ScanTranslator method translate.

// ScanMapFunction
void translate(final TableScan tableScan, final String queryLogicalId, final String logicalOpId, final TranslatorContext context, Map<String, DelegatingSystemDescriptor> systemDescriptors, Map<String, MessageStream<SamzaSqlInputMessage>> inputMsgStreams) {
    StreamApplicationDescriptor streamAppDesc = context.getStreamAppDescriptor();
    List<String> tableNameParts = tableScan.getTable().getQualifiedName();
    String sourceName = SqlIOConfig.getSourceFromSourceParts(tableNameParts);
    Validate.isTrue(relMsgConverters.containsKey(sourceName), String.format("Unknown source %s", sourceName));
    SqlIOConfig sqlIOConfig = systemStreamConfig.get(sourceName);
    final String systemName = sqlIOConfig.getSystemName();
    final String streamId = sqlIOConfig.getStreamId();
    final String source = sqlIOConfig.getSource();
    final boolean isRemoteTable = sqlIOConfig.getTableDescriptor().isPresent() && (sqlIOConfig.getTableDescriptor().get() instanceof RemoteTableDescriptor || sqlIOConfig.getTableDescriptor().get() instanceof CachingTableDescriptor);
    // descriptor to load the local table.
    if (isRemoteTable) {
        return;
    }
    // set the wrapper input transformer (SamzaSqlInputTransformer) in system descriptor
    DelegatingSystemDescriptor systemDescriptor = systemDescriptors.get(systemName);
    if (systemDescriptor == null) {
        systemDescriptor = new DelegatingSystemDescriptor(systemName, new SamzaSqlInputTransformer());
        systemDescriptors.put(systemName, systemDescriptor);
    } else {
        /* in SamzaSQL, there should be no systemDescriptor setup by user, so this branch happens only
       * in case of Fan-OUT (i.e., same input stream used in multiple sql statements), or when same input
       * used twice in same sql statement (e.g., select ... from input as i1, input as i2 ...), o.w., throw error */
        if (systemDescriptor.getTransformer().isPresent()) {
            InputTransformer existingTransformer = systemDescriptor.getTransformer().get();
            if (!(existingTransformer instanceof SamzaSqlInputTransformer)) {
                throw new SamzaException("SamzaSQL Exception: existing transformer for " + systemName + " is not SamzaSqlInputTransformer");
            }
        }
    }
    InputDescriptor inputDescriptor = systemDescriptor.getInputDescriptor(streamId, new NoOpSerde<>());
    if (!inputMsgStreams.containsKey(source)) {
        MessageStream<SamzaSqlInputMessage> inputMsgStream = streamAppDesc.getInputStream(inputDescriptor);
        inputMsgStreams.put(source, inputMsgStream.map(new SystemMessageMapperFunction(source, queryId)));
    }
    MessageStream<SamzaSqlRelMessage> samzaSqlRelMessageStream = inputMsgStreams.get(source).filter(new FilterSystemMessageFunction(sourceName, queryId)).map(new ScanMapFunction(sourceName, queryId, queryLogicalId, logicalOpId));
    context.registerMessageStream(tableScan.getId(), samzaSqlRelMessageStream);
}