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How to resolve "Failed to infer schema... error found in byte" when inferring schema in Panther


When trying to infer a schema from a sample of log files, Panther presents the following error: Failed to infer schema: failed to parse line [1] as JSON: ReadString expects '' or n, but found , error in #1 byte of ...|{|..., bigger context ...|{|...

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To resolve this issue, please ensure your log files are written in JSONL format. This means that each JSON event object must fit on a single line in the file. There are many preprocessors that offer this functionality (i.e. Cribl), but in a pinch, any computer with a bash shell can convert the files using the following steps:

  1. Place all of your sample log files into a separate directory (if they aren't already).
  2. Open a bash terminal (or equivalent), and change directory into the folder with the sample logs.
  3. Run the following bash script:
for f in azure_*; do (cat "${f}"; echo) >> sample_logs.jsonl; done

You should now be able to use the file sample_logs.jsonl to infer a schema.


This issue is because currently Panther doesn't support parsing JSON objects which span multiple lines.