Package org.apache.log4j.db

Class CustomSQLDBReceiver

  • All Implemented Interfaces:
    Pauseable, Plugin, Component, org.apache.log4j.spi.OptionHandler, Thresholdable, org.apache.log4j.xml.UnrecognizedElementHandler
    public class CustomSQLDBReceiver
extends Receiver
implements Pauseable, org.apache.log4j.xml.UnrecognizedElementHandler
    Converts log data stored in a database into LoggingEvents.

    NOTE: This receiver cannot yet be created through Chainsaw's receiver panel. It must be created through an XML configuration file.

    This receiver supports database configuration via ConnectionSource, in the org.apache.log4j.db package: DriverManagerConnectionSource, DataSourceConnectionSource, JNDIConnectionSource

    This database receiver differs from DBReceiver in that this receiver relies on custom SQL to retrieve logging event data, where DBReceiver requires the use of a log4j-defined schema.

    A 'refreshMillis' int parameter controls SQL execution. If 'refreshMillis' is zero (the default), the receiver will run only one time. If it is set to any other numeric value, the SQL will be executed on a recurring basis every 'refreshMillis' milliseconds.

    The receiver closes the connection and acquires a new connection on each execution of the SQL (use pooled connections if possible).

    If the SQL will be executing on a recurring basis, specify the IDField param - the column name holding the unique identifier (int) representing the logging event.

    As events are retrieved, the column represented by IDField is examined and the largest value is held and used by the next execution of the SQL statement to avoid retrieving previously processed events.

    As an example, the IDField references a 'COUNTER' (int, auto-increment, unique) column. The first execution of the SQL statement returns 500 rows, with a final value in the COUNTER field of 500.

    The SQL statement is manipulated prior to the next execution, adding ' WHERE COUNTER > 500' to the statement to avoid retrieval of previously processed events.

    The select statement must provide ALL fields which define a LoggingEvent.

    The SQL statement MUST include the columns: LOGGER, TIMESTAMP, LEVEL, THREAD, MESSAGE, NDC, MDC, CLASS, METHOD, FILE, LINE, PROPERTIES, THROWABLE

    Use ' AS ' in the SQL statement to alias the SQL's column names to match your database schema. (see example below).

    Include all fields in the SQL statement, even if you don't have data for the field (specify an empty string as the value for columns which you don't have data).

    The TIMESTAMP column must be a datetime.

    Both a PROPERTIES column and an MDC column are supported. These fields represent Maps on the logging event, but require the use of string concatenation database functions to hold the (possibly multiple) name/value pairs in the column.

    For example, to include both 'userid' and 'lastname' properties in the logging event (from either the PROPERTIES or MDC columns), the name/value pairs must be concatenated together by your database.

    The resulting PROPERTIES or MDC column must have data in this format: {{name, value, name2, value2}}

    The resulting PROPERTIES column would contain this text: {{userid, someone, lastname, mylastname}}

    Here is an example of concatenating a PROPERTIES or MDC column using MySQL's concat function, where the 'application' and 'hostname' parameters were fixed text, but the 'log4jid' key's value is the value of the COUNTER column:

    concat("{{application,databaselogs,hostname,mymachine,log4jid,", COUNTER, "}}") as PROPERTIES

    log4jid is a special property that is used by Chainsaw to represent an 'ID' field. Specify this property to ensure you can map events in Chainsaw to events in the database if you need to go back and view events at a later time or save the events to XML for later analysis.

    Here is a complete MySQL SQL statement which can be used to provide events to Chainsaw (note how in the example below, there is no column in logtable representing the throwable, so an empty string is passed in and an ALIAS is still defined):

    select myloggercolumn as LOGGER, mytimestampcolumn as TIMESTAMP, mylevelcolumn as LEVEL, mythreadcolumn as THREAD, mymessagecolumn as MESSAGE, myndccolumn as NDC, mymdccolumn as MDC, myclasscolumn as CLASS, mymethodcolumn as METHOD, myfilecolumn as FILE, mylinecolumn as LINE, concat("{{application,databaselogs,hostname,mymachine, log4jid,", COUNTER,"}}") as PROPERTIES, "" as THROWABLE from logtable

    Author:
    Scott Deboy <sdeboy@apache.org>

    • Constructor Detail

      • CustomSQLDBReceiver

        public CustomSQLDBReceiver()

    • Method Detail

      • activateOptions

        public void activateOptions()
        Specified by:
        activateOptions in interface org.apache.log4j.spi.OptionHandler

      • setRefreshMillis

        public void setRefreshMillis​(int refreshMillis)

      • getRefreshMillis

        public int getRefreshMillis()

      • getConnectionSource

        public ConnectionSource getConnectionSource()
        Returns:
        Returns the connectionSource.

      • setConnectionSource

        public void setConnectionSource​(ConnectionSource connectionSource)
        Parameters:
        connectionSource - The connectionSource to set.

      • close

        public void close()

      • shutdown

        public void shutdown()
        Description copied from interface: Plugin
        Call when the plugin should be stopped.
        Specified by:
        shutdown in interface Plugin

      • setSql

        public void setSql​(String s)

      • getSql

        public String getSql()

      • setIDField

        public void setIDField​(String id)

      • getIDField

        public String getIDField()

      • setPaused

        public void setPaused​(boolean p)
        Description copied from interface: Pauseable
        Set paused state.
        Specified by:
        setPaused in interface Pauseable
        Parameters:
        p - new value

      • isPaused

        public boolean isPaused()
        Description copied from interface: Pauseable
        Get paused state.
        Specified by:
        isPaused in interface Pauseable
        Returns:
        paused state.

      • parseUnrecognizedElement

        public boolean parseUnrecognizedElement​(Element element,
                                        Properties props)
                                 throws Exception
        Specified by:
        parseUnrecognizedElement in interface org.apache.log4j.xml.UnrecognizedElementHandler
        Throws:
        Exception