CdcMain (Ignite 2.15.0)

java.lang.Object
- org.apache.ignite.internal.cdc.CdcMain

All Implemented Interfaces:

Runnable
```
public class CdcMain
extends Object
implements Runnable
```
Change Data Capture (CDC) application. The application runs independently of Ignite node process and provides the ability for the CdcConsumer to consume events(CdcEvent) from WAL segments. The user should provide CdcConsumer implementation with custom consumption logic. Ignite node should be explicitly configured for using CdcMain.
1. Set DataRegionConfiguration.setCdcEnabled(boolean) to true.
2. Optional: Set DataStorageConfiguration.setCdcWalPath(String) to path to the directory to store WAL segments for CDC.
3. Optional: Set DataStorageConfiguration.setWalForceArchiveTimeout(long) to configure timeout for force WAL rollover, so new events will be available for consumptions with the predicted time.
When DataStorageConfiguration.getCdcWalPath() is true then Ignite node on each WAL segment rollover creates hard link to archive WAL segment in DataStorageConfiguration.getCdcWalPath() directory. CdcMain application takes segment file and consumes events from it. After successful consumption (see CdcConsumer.onEvents(Iterator)) WAL segment will be deleted from directory. Several Ignite nodes can be started on the same host. If your deployment done with custom consistent id then you should specify it via IgniteConfiguration.setConsistentId(Serializable) in provided IgniteConfiguration. Application works as follows:
1. Searches node work directory based on provided IgniteConfiguration.
2. Awaits for the creation of CDC directory if it not exists.
3. Acquires file lock to ensure exclusive consumption.
4. Loads state of consumption if it exists.
5. Infinitely waits for new available segment and processes it.
See Also:

DataRegionConfiguration.setCdcEnabled(boolean), DataStorageConfiguration.setCdcWalPath(String), DataStorageConfiguration.setWalForceArchiveTimeout(long), CdcCommandLineStartup, CdcConsumer, DataStorageConfiguration.DFLT_WAL_CDC_PATH

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`BINARY_META_DIR` Binary metadata metric name.
`static String`	`CDC_DIR` Cdc directory metric name.
`protected CdcConfiguration`	`cdcCfg` Change Data Capture configuration.
`static String`	`COMMITTED_SEG_IDX` Committed segment index metric name.
`static String`	`COMMITTED_SEG_OFFSET` Committed segment offset metric name.
`static String`	`CUR_SEG_IDX` Current segment index metric name.
`static String`	`ERR_MSG`
`static String`	`LAST_SEG_CONSUMPTION_TIME` Last segment consumption time.
`static String`	`MARSHALLER_DIR` Marshaller metric name.
`static String`	`META_UPDATE` Metadata update time.
`static String`	`STATE_DIR` State dir.

Constructor Summary

Constructors
Constructor and Description

CdcMain(IgniteConfiguration cfg, GridSpringResourceContext ctx, CdcConfiguration cdcCfg)

Constructors
Constructor and Description
`CdcMain(IgniteConfiguration cfg, GridSpringResourceContext ctx, CdcConfiguration cdcCfg)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`cdcInstanceName(String igniteInstanceName)`
`void`	`consumeWalSegmentsUntilStopped()` Waits and consumes new WAL segments until stopped.
`protected CdcConsumerState`	`createState(Path stateDir)` Creates consumer state.
`void`	`run()` Runs Change Data Capture.
`void`	`runX()` Runs Change Data Capture application with possible exception.
`void`	`stop()` Stops the application.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - ERR_MSG
```
public static final String ERR_MSG
```
    See Also:
    
    Constant Field Values
  - STATE_DIR
```
public static final String STATE_DIR
```
    State dir.
    
    See Also:
    
    Constant Field Values
  - CUR_SEG_IDX
```
public static final String CUR_SEG_IDX
```
    Current segment index metric name.
    
    See Also:
    
    Constant Field Values
  - COMMITTED_SEG_IDX
```
public static final String COMMITTED_SEG_IDX
```
    Committed segment index metric name.
    
    See Also:
    
    Constant Field Values
  - COMMITTED_SEG_OFFSET
```
public static final String COMMITTED_SEG_OFFSET
```
    Committed segment offset metric name.
    
    See Also:
    
    Constant Field Values
  - LAST_SEG_CONSUMPTION_TIME
```
public static final String LAST_SEG_CONSUMPTION_TIME
```
    Last segment consumption time.
    
    See Also:
    
    Constant Field Values
  - META_UPDATE
```
public static final String META_UPDATE
```
    Metadata update time.
    
    See Also:
    
    Constant Field Values
  - BINARY_META_DIR
```
public static final String BINARY_META_DIR
```
    Binary metadata metric name.
    
    See Also:
    
    Constant Field Values
  - MARSHALLER_DIR
```
public static final String MARSHALLER_DIR
```
    Marshaller metric name.
    
    See Also:
    
    Constant Field Values
  - CDC_DIR
```
public static final String CDC_DIR
```
    Cdc directory metric name.
    
    See Also:
    
    Constant Field Values
  - cdcCfg
```
protected final CdcConfiguration cdcCfg
```
    Change Data Capture configuration.
- Constructor Detail
  - CdcMain
```
public CdcMain(IgniteConfiguration cfg,
               GridSpringResourceContext ctx,
               CdcConfiguration cdcCfg)
```
    Parameters:
    
    cfg - Ignite configuration.
    
    ctx - Spring resource context.
    
    cdcCfg - Change Data Capture configuration.
- Method Detail
  - run
```
public void run()
```
    Runs Change Data Capture.
    
    Specified by:
    
    run in interface Runnable
  - runX
```
public void runX()
          throws Exception
```
    Runs Change Data Capture application with possible exception.
    
    Throws:
    
    Exception
  - createState
```
protected CdcConsumerState createState(Path stateDir)
```
    Creates consumer state.
  - consumeWalSegmentsUntilStopped
```
public void consumeWalSegmentsUntilStopped()
```
    Waits and consumes new WAL segments until stopped.
  - stop
```
public void stop()
```
    Stops the application.
  - cdcInstanceName
```
public static String cdcInstanceName(String igniteInstanceName)
```

Class CdcMain

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ERR_MSG

STATE_DIR

CUR_SEG_IDX

COMMITTED_SEG_IDX

COMMITTED_SEG_OFFSET

LAST_SEG_CONSUMPTION_TIME

META_UPDATE

BINARY_META_DIR

MARSHALLER_DIR

CDC_DIR

cdcCfg

Constructor Detail

CdcMain

Method Detail

run

runX

createState

consumeWalSegmentsUntilStopped

stop

cdcInstanceName