Setting Logging Properties
Cromwell accepts two properties for controlling logging. You can set these properties via a Java system property on the command line using
$ java -DLOG_LEVEL=DEBUG -jar cromwell.jar server
Alternatively, you can also set the log level via an environment variable:
export LOG_LEVEL=DEBUG java -jar cromwell.jar server
If you set same property via a system property, and an environment variable, the system property overrides the environment variable.
Cromwell outputs log in one of two formats, either
standard. You can change the format of the logs by setting the property to
standardmode, your logs will be written without ANSI escape code coloring, with a layout more appropriate for server logs.
prettymode, your logs are output in a colorful, easier to read format, more appropriate for a single workflow run.
The default mode for server is
standard, while the default when running a single worklow is
pretty. You can explicitly specify the format by running cromwell with:
java -DLOG_MODE=pretty -jar cromwell.jar server
By default, Cromwell outputs messages at a
INFO. Sometimes, you may want more or less information logged. For example, while debugging an issue you may want to increase the amount information in the logs temporarily. Alternatively, the standard level may be too verbose, and you may only want Cromwell to log warnings and errors.
You can set the level via the property
LOG_LEVEL to any one of the values:
OFF. The default log level is
java -DLOG_LEVEL=DEBUG -jar cromwell.jar server
While a workflow is running, Cromwell generates a log file specifically for the workflow. After the workflow completes, to clear up local disk space, Cromwell deletes the local copy of this log file. See the Configuration section on logs for more information on preventing cromwell from deleting each workflow log.
Before Cromwell deletes the files and before the workflow completes, you can configure Cromwell to copy the workflow
logs to various locations. Normally, you'll want to copy the log to a remote bucket or directory. To specify the remote
directory to copy the logs to, use the separate Workflow Option
As each call in a workflow runs, it generates output to the standard output and standard error. This output is stored per call in call log files. Additionally, depending on the backend, specific per call backand logs may be generated.
All of these call logs may be copied at the end of a workflow to a remote directory. Configure this directory by setting the Workflow Option