Write to log transform Icon Write to log

Description

The Write To Log transform writes information to the Hop logging system.

Typical use cases are logging specific values or custom logging messages to the Hop logs.

be careful when writing variables or fields for (unencrypted) passwords or other sensitive information to the Hop logging system!

If no fields are specified it will write out all fields to the log. If at least one field is specified it will only print out that field. Parameters and variables must be specified in the Log message section.

A Logging level must be set. Set the Log detail level to Basic if you want variables to be printed out.

Example to print a parameter or variable in the Log Message section: COUNTER: ${COUNTER}

If no fields exist, you will have to use a "Generate rows" transform to create a dummy row in order to print variables or parameters.

If an error stops anything from being written to the log, then disable the Hops that fail, and add logging just before the failure, and re-run

Supported Engines

Hop Engine

Supported

Spark

Maybe Supported

Flink

Maybe Supported

Dataflow

Maybe Supported

Options

Option Description

Transform Name

Name of the transform this name has to be unique in a single pipeline.

Log level

The logging level to use.

Print header

Whether or not the column names for data values is printed. In the example below, this value has been set to false, so only the actual values (3, 4) are printed.

Limit rows

Limit the number of rows given by the parameter "Nr. of rows to print".

Nr. of rows to print

The number of rows to print when option "limit rows" is checked.

Write to log

The text to use in the logging line(s).

Fields

The data from fields that should we written to the log.

Example log output

2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 - ----------> Linenr 1----------------------------
2020/05/14 12:30:52 - Write to log.0 - test log
2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 -  3
2020/05/14 12:30:52 - Write to log.0 -  4
2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 - ====================
2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 - ----------> Linenr 2----------------------------
2020/05/14 12:30:52 - Write to log.0 - test log
2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 -  3
2020/05/14 12:30:52 - Write to log.0 -  4
2020/05/14 12:30:52 - Write to log.0 -
2020/05/14 12:30:52 - Write to log.0 - ====================