FME Flow Debugging Toolbox: Troubleshooting with Logs

Introduction

Log files can be helpful for solving any type of issue in FME Flow. The first step is to determine which log file will contain relevant information.

Every job run by FME Flow produces a log file with the details of the translation. If you are encountering a problem with a job, start by reviewing its log. 

In addition to jobs, nearly every process run by FME Flow is recorded in a system log file. Log files are organized by FME Flow component, process, and service. Consult these logs for general issues in FME Flow or to supplement information provided in a job log. 

This article is best used for general investigation and diagnostics. Search keywords and errors on FME Community to find resources. Make sure to review the complete list of FME Flow Troubleshooting Guides when you identify the source of the issue. 
 

Debugging Disclaimer

Before you begin troubleshooting, carefully consider which tool will be most effective for solving the problem you are encountering in FME Flow. Not every tool or strategy will be useful or relevant to your issue. However, any progress is useful since troubleshooting is often a process of elimination.

The following sections may provide example directions for using each tool, but availability and instructions may differ between operating systems, deployment types, software versions, and other system factors. 

Always use caution or contact your FME Flow administrator when making any changes to your installation. 
 

Introduction to Log Files

Learn about the different FME Flow log types and basic troubleshooting skills in less than 7 minutes with this introductory video!


This video was recorded using FME 2021.0, the interface may be different but the concepts are the same.

Where to Find Logs

FME Flow log files can be accessed from the browser, desktop, or FME Flow REST API. All FME Flow logs are found in the system ‘logs’ folder, with the exception of Automation logs. 

From a Browser

Jobs

Job activity is organized on the Jobs page by status. Click any job to view its log file. 



Job logs accessed through the Web UI are preceded by additional summary information, such as status, request data, and result data. 


The Request Data section lists parameter values that may be helpful for investigating invalid input.

FME Flow System Logs

FME Flow system logs can be found in Resources > Logs. 

Log folders are organized by FME Flow component. For example, FME Flow Engines are responsible for running jobs, so job log folders are located inside the engine folder. View the log files through the web UI or select and download. 


Each FME Flow component has a named folder containing relevant log files. 

Automation Logs

Automation logs are not stored with all other FME Flow logs. Access an Automation log from the main menu of your Automation. See the documentation for Working with Automation Logs for more information.


Automation logs can be accessed from the Automation’s Menu.

From Operating System

Log files can also be accessed from a system directory, inside the FME Flow System Share. Accessing the log files from a system directory gives the added benefit of being able to efficiently search a folder for error messages. 

The System Share location is set at installation and contains all system log files:

<FMEFlowSystemShare>\resources\logs\engine\current\jobs\

For example, the default location for log files on a default Windows System Share is:

C:\ProgramData\Safe Software\FMEFlow\resources\logs

The default ProgramData folder is hidden on a Windows OS by default. From the File Explorer menu, select View > Hidden Items to expose the folder. 

From the REST API

Use the FME Flow REST API (V3) to request workflow logs over the web. 

Download job log file

Get the log of an automation workflow

GET /automations/workflows/< id >/log

Retrieve job log 

GET /transformations/jobs/id/< jobid >/log


A ‘Retrieve job log’ request made through the FME Flow REST documentation page returns a job log in the response body.

See Getting Started with the FME Flow REST API for relevant examples of using the REST API. 

Inside Log Folders

Log files are grouped in subdirectories organized by FME Flow component. 

The component directories are then split into ‘current’ or ‘old’ folders (see Cleaning Up FME Flow Logs and Other Files for more information). Refer to the file datestamps to locate logs relevant to your issue. 

Within each folder, individual log files are written for different processes. About Log Files lists the general content for each log file. It is also useful to reference the FME Flow Architecture in order to understand which components are responsible for which processes. 

Core

This folder contains logs regarding the main functionality and configurations of FME Flow. For example: 

• fmeserver.log (note, this is still called fmeserver.log and not fmeflow.log)
• core, core process monitor
• tasks (backup and restore, projects)
• publishers (triggers)
• triggers (external actions)
• fmedirectoryserver.log (LDAP)

Engine

This folder contains job logs, the engine process monitor logs, and individual engine logs. Please note that the individual engine logs might have very few messages because the log is refreshed every time the engine restarts.
 

Queue

This folder contains log files for the memurai (FME Flow 2023+ win64) or redis (all other FME Flow versions) job queue.
 

Service

This folder contains log files for the FME Flow services, including the job submitter, data download, data upload, REST API, and token services.
 

Tomcat

This folder contains log files for the FME Flow's web application server (Apache Tomcat) and access logs.
 

Tips for Troubleshooting with Logs

Log File Messages

Messages in all FME Flow log files are structured the same way. For each entry, a status is returned:

• INFORM - Important information that should be logged under normal conditions.
• WARN - This might be a problem or it might not.
• ERROR - Definitely a problem that should be investigated.
• FATAL - Overall application or system failure that should be investigated immediately.

Please see Deep Dive on FME Flow Log File Patterns for an advanced overview of log messaging within Tomcat and FME Flow logs, with examples.

Navigating Log Files

For jobs, start with the job log (Engine > Jobs). 
For automations, start with the automation log and the core folder.
For general investigations, start with the following logs:

• fmeserver.log (Core folder)
• fmeprocessmonitorengine.log (Engine folder)
• catalina.log (Tomcat folder)

Core Logs 

• When FME Flow components (such as the server, database, queue, scheduler, etc.) are not starting, running, or stopping properly, reference the fmeserver.log and fmeprocessmonitorcore.log.
• When an Automation’s log is insufficient, check the publishers (triggers) or subscribers (external actions) log folders.
• The tasks folder contains useful for troubleshooting backup/restore events and project issues. Use it in conjunction with the fmeconfiguration.log.

Engine Logs

• For job failures, find the job ID within the jobs folder. The job log will often contain an error or warning message that may give more context. 
• The fmeprocessmonitorengine.log is useful when troubleshooting engine crashes or disconnections.

Other Logs

• For FME Flow web user interface, user login, or REST API Issues, the catalina.log under the tomcat log folder is usually a good place to start. Test for errors with the browser’s Developer Tools for more information.
• If a job is demonstrating an issue with an FME Flow web service (data download, data streaming, uploading a file, authentication, REST requests, etc.) then find the relevant log in the service folder. 
• If you suspect a new FME Flow installation or upgrade has gone awry, please review the installation folder for details about the process. 

Log Statistics

Timestamps and Statistics 
See our 'Post-Mortem Performance Tuning' for a general analysis of FME log file timestamps and statistics. 

Please note that the FME Flow REST API and Web UI may report different job statistics than the job log. Please review 'Monitoring FME Flow Job Activity using the REST API ' for a discussion and overview. 

Additional Resources

• See FME Flow Troubleshooting: Log Files for answers to common questions about managing and troubleshooting log files
• Review the FME Flow Troubleshooting Guides for common questions and solutions.
• Follow along with Debugging for Workspaces for troubleshooting strategies and methodology.  
• Search the FME Community for keywords related to your problem
• Contact Safe Software Support and include any logs, screenshots, or information captured while troubleshooting.