> For the complete documentation index, see [llms.txt](https://flow-docs.cloudio.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://flow-docs.cloudio.io/advanced-topics/post-process.md).

# Post Process

Everytime the events are posted to the output, you can perform any post process, if need be, using the `Post Process` script. You can use any standard Java or Groovy code in the post process script.

![](/files/-LyaoJpZXoGflYDylwY6)

### Variables Available

The following are the variables available to the script

| Variable        | Description                                                              | Output Type  |
| --------------- | ------------------------------------------------------------------------ | ------------ |
| flowCode        | Flow code                                                                | All          |
| outputEventType | Table name in the target DB                                              | All          |
| inputEventType  | Table/Object name in the source system                                   | All          |
| inputType       | Input Connector Type e.g. Oracle, MySQL                                  | All          |
| outputType      | Output Connector Type e.g. Oracle, MySQL                                 | All          |
| logger          | Log4j logger for debug purpose                                           | All          |
| db              | An instance of [FlowScript](/advanced-topics/post-process.md#flowscript) | All          |
| count           | Total number of events processed                                         | All          |
| events          | List of events `List<Message>`                                           | All Database |
| errorCount      | Total number of events erred out                                         | All          |
| con             | Output database connection used to post the events                       | All Database |
| producer        | The producer used to post the events                                     | Kafka        |
| key             | S3 file Key used to post the events                                      | Amazon S3    |

### FlowScript (db) <a href="#flowscript" id="flowscript"></a>

{% code title="FlowScrip.java" %}

```java
interface FlowScript {

  /**
   * <p>Call this to get a connection to the output database. Throws exception
   * if the output type is not a database. If you call multiple times,
   * then the same connection will be returned.</p>
   * 
   * @return {@link IOConnection}
   * @throws Exception
   */
  IOConnection getTargetDBConnection() throws Exception;

  /**
   * <p>Call this to get a connection to the input database. Throws exception
   * if the input type is not a database. If you call multiple times,
   * then the same connection will be returned.</p>
   * 
   * @return {@link IOConnection}
   * @throws Exception
   */
  IOConnection getSourceDBConnection() throws Exception;

  /**
   * <p>Call this to get a new connection to the output database, discarding any
   * existing connection. Throws exception if the output type is not a database.
   * If you call multiple times, then the same connection will be returned.</p>
   * 
   * <p>This is useful when you want to make a Redshift call after an 
   * exception as shown below</p>
   * 
   * <pre>
   * Connection con = null;
   * 
   * try {
   * 
   *   con = db.getTargetDBConnection();
   *   
   *   Map<Integer, Object> result = SQL.createCall(con, "my_proc(?, ?)")
   *     .bind(1, "bind value 1")
   *     .registerOutParameter(2, Types.VARCHAR2)
   *     .execute();
   *     
   * } catch (Exception e) {
   * 
   *   con = db.resetAndGetTargetDBConnection();
   *   
   *   SQL.createCall(con, "my_handle_error_proc(?)")
   *     .bind(1, e.getMessage())
   *     .execute();
   *     
   * }
   * </pre>
   * @return {@link IOConnection}
   * @throws Exception
   */
  IOConnection resetAndGetTargetDBConnection() throws Exception;

  /**
   * <p>Call this to get a new connection to the input database, discarding any
   * existing connection. Throws exception if the input type is not a database.
   * If you call multiple times, then the same connection will be returned.</p>
   * 
   * <p>This is useful when you want to make a Redshift call after an 
   * exception as shown below</p>
   * 
   * <pre>
   * Connection con = null;
   * 
   * try {
   * 
   *   con = db.getTargetDBConnection();
   *   
   *   Map<Integer, Object> result = SQL.createCall(con, "my_proc(?, ?)")
   *     .bind(1, "bind value 1")
   *     .registerOutParameter(2, Types.VARCHAR2)
   *     .execute();
   *     
   * } catch (Exception e) {
   * 
   *   con = db.resetAndGetTargetDBConnection();
   *   
   *   SQL.createCall(con, "my_handle_error_proc(?)")
   *     .bind(1, e.getMessage())
   *     .execute();
   *     
   * }
   * </pre>
   * @return {@link IOConnection}
   * @throws Exception
   */
  IOConnection resetAndGetSourceDBConnection() throws Exception;

  /**
   * This is called by FLOW after the script is executed
   */
  void close();

  /**
   * This is called by FLOW after successful execution of the script to commit 
   * both the input and output connections when used.
   * 
   * @throws SQLException
   */
  void commit() throws SQLException;

  /**
   * This is called by FLOW after unsuccessful execution of the script to 
   * rollback both the input and output connections when used.
   * 
   * @throws SQLException
   */
  void rollback() throws Exception;

  /**
   * Same as logger.debug
   * @param msg
   */
  void debug(String msg);

  /**
   * Retrieves the value of a given variable
   *
   * @param variableName
   * @return the variable value
   * @throws Exception
   */
  String env(String variableName) throws Exception;

}
```

{% endcode %}