Examples with QueryTranslator org.apache.samza.sql.translator.QueryTranslator used on opensource projects

Example 1 with QueryTranslator

use of org.apache.samza.sql.translator.QueryTranslator in project samza by apache.

the class SamzaSqlApplication method describe.

@Override
public void describe(StreamApplicationDescriptor appDescriptor) {
    try {
        // TODO: Introduce an API to return a dsl string containing one or more sql statements.
        List<String> dslStmts = SamzaSqlDslConverter.fetchSqlFromConfig(appDescriptor.getConfig());
        Map<Integer, TranslatorContext> translatorContextMap = new HashMap<>();
        // 1. Get Calcite plan
        List<String> inputSystemStreams = new LinkedList<>();
        List<String> outputSystemStreams = new LinkedList<>();
        Collection<RelRoot> relRoots = SamzaSqlApplicationConfig.populateSystemStreamsAndGetRelRoots(dslStmts, appDescriptor.getConfig(), inputSystemStreams, outputSystemStreams);
        // 2. Populate configs
        SamzaSqlApplicationConfig sqlConfig = new SamzaSqlApplicationConfig(appDescriptor.getConfig(), inputSystemStreams, outputSystemStreams);
        // 3. Translate Calcite plan to Samza stream operators
        QueryTranslator queryTranslator = new QueryTranslator(appDescriptor, sqlConfig);
        SamzaSqlExecutionContext executionContext = new SamzaSqlExecutionContext(sqlConfig);
        // QueryId implies the index of the query in multiple query statements scenario. It should always start with 0.
        int queryId = 0;
        for (RelRoot relRoot : relRoots) {
            LOG.info("Translating relRoot {} to samza stream graph with queryId {}", relRoot, queryId);
            TranslatorContext translatorContext = new TranslatorContext(appDescriptor, relRoot, executionContext);
            translatorContextMap.put(queryId, translatorContext);
            queryTranslator.translate(relRoot, sqlConfig.getOutputSystemStreams().get(queryId), translatorContext, queryId);
            queryId++;
        }
        // 4. Set all translator contexts
        /*
       * TODO When serialization of ApplicationDescriptor is actually needed, then something will need to be updated here,
       * since translatorContext is not Serializable. Currently, a new ApplicationDescriptor instance is created in each
       * container, so it does not need to be serialized. Therefore, the translatorContext is recreated in each container
       * and does not need to be serialized.
       */
        appDescriptor.withApplicationTaskContextFactory(new ApplicationTaskContextFactory<SamzaSqlApplicationContext>() {

            @Override
            public SamzaSqlApplicationContext create(ExternalContext externalContext, JobContext jobContext, ContainerContext containerContext, TaskContext taskContext, ApplicationContainerContext applicationContainerContext) {
                return new SamzaSqlApplicationContext(translatorContextMap);
            }
        });
    } catch (RuntimeException e) {
        LOG.error("SamzaSqlApplication threw exception.", e);
        throw e;
    }
}