How to ETL multiple files using Scriptella?

问题

I am having multiple log files 1.csv,2.csv and 3.csv generated by a log report. I want to read those files and parse them concurrently using Scriptella.

回答1:

Scriptella does not provide parallel job execution out of the box. Instead you should use a job scheduler provided by an operating system or a programming environment (e.g. run multiple ETL files by submitting jobs to an ExecutorService).

Here is a working example to import a single file specified as a system property:

ETL file:

<!DOCTYPE etl SYSTEM "http://scriptella.javaforge.com/dtd/etl.dtd">
<etl>
    <connection id="in" driver="csv" url="$input"/>
    <connection id="out" driver="text"/>
    <query connection-id="in">
        <script connection-id="out">
            Importing: $1, $2
        </script>
    </query>
</etl>

Java code to run files in parallel:

//Imports 3 csv files in parallel using a fixed thread pool
public class ParallelCsvTest {
    public static void main(String[] args) throws EtlExecutorException, MalformedURLException, InterruptedException {
        final ExecutorService service = Executors.newFixedThreadPool(3);
        for (int i=1;i<=3;i++) {
            //Pass a name as a parameter to ETL file, e.g. input<i>.csv
            final Map<String,?> map = Collections.singletonMap("input", "input"+i+".csv");
            EtlExecutor executor = EtlExecutor.newExecutor(new File("parallel.csv.etl.xml").toURI().toURL(), map);
            service.submit((Callable<ExecutionStatistics>)executor);
        }
        service.shutdown();
        service.awaitTermination(10, TimeUnit.SECONDS);
    }
}

Tu run this example create 3 csv files input1.csv, input2.csv and input3.csv and put them in the current working directory. Example of the CSV file:

Level, Message
INFO,Process 1 started
INFO,Process 1 stopped

来源：https://stackoverflow.com/questions/12383025/how-to-etl-multiple-files-using-scriptella

标签

etl

scriptella