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Logs

The Logs tab displays the workflow runner's log fetched from the run's S3 output directory. Available on the run detail page. For Nextflow runs, this is the *.nextflow.log file; for WDL it is the miniwdl log.

Behavior

  • Multiple logs: After resume cycles, multiple log files may exist. Tracker displays the most recent and shows a warning.
  • Large files: Only the last ~1 MB is shown, with a truncation warning indicating full file size. The tail is typically the most useful for debugging.
  • Refresh: A button reloads the log without a full page refresh -- useful during active runs.

Error Messages

Message Cause
No output directory configured Run has no output_dir set
No log files found No *.nextflow.log files in the output directory
Multiple log files found Multiple logs exist; most recent is shown
Log file is X MB. Showing last 1 MB. Log exceeds preview limit; tail displayed
Access denied to S3 bucket Tracker lacks S3 read permission
S3 bucket not found Bucket in the output directory does not exist
Output directory is not an S3 path Log preview requires an S3 URI