Workflow Configuration And Parameterization

workflow-configuration-and-parameterization

Summary

Configure and parameterize a Nextflow-based LC-HRMS metabolomics workflow by specifying tool-specific configuration files, reference libraries, input paths, and container backends before execution. This skill ensures reproducible, portable workflow execution across local, containerized, and HPC environments.

When to use

When preparing to execute the Nextflow4MS-DIAL workflow on raw LC-HRMS metabolomics data (.mzML or .abf files), you must configure MS-DIAL and MS-FLO parameters, supply MS1/MS2 spectral libraries, specify input/output directories, and select the appropriate container backend (Docker for local execution, Singularity for HPC) before invoking the pipeline.

When NOT to use

• Input data is not in .mzML or .abf format; convert with ProteoWizard msConvert or Reifycs Abf Converter first.
• You lack the MS-DIAL and MS-FLO configuration files and spectral libraries specific to your analytical method; obtain or generate these before workflow execution.
• The computing environment does not support Docker or Singularity containers; verify container engine availability and HPC scheduler compatibility before configuration.

Inputs

• Raw LC-HRMS data files (.mzML or .abf format)
• MS-DIAL configuration file (msdial_params.txt)
• MS-FLO configuration file (msflo_params.ini)
• MS1 spectral library file (ms1_lib.txt)
• MS2 spectral library file (ms2_lib.msp)
• Nextflow configuration files (conf/base.config, conf/HiPerGator.config)
• Java runtime (version 11 or later)
• Nextflow installation (≥22.10.0)
• Docker or Singularity container runtime

Outputs

• Execution report (execution_report.html with runtime and resource metrics)
• Execution timeline (execution_timeline.html showing per-process timing)
• Execution log (logs/execution.log containing metadata, parameters, and process-level details)
• Processed LC-HRMS feature tables (.tsv files converted from .msdial output)

How to apply

First, prepare MS-DIAL configuration (msdial_params.txt) and MS-FLO configuration (msflo_params.ini) files specific to your analytical method, placing them in the data/ folder. Add MS1 and MS2 spectral library files (ms1_lib.txt and ms2_lib.msp) to the same directory. Then, configure the Nextflow execution profile: use the docker profile in conf/base.config for local execution, or the singularity profile (defined in conf/HiPerGator.config) for HPC systems. Verify that reference file paths in conf/base.config match your setup and that file naming conventions follow the workflow's expectations (underscores are safe; avoid special characters). Finally, invoke the workflow with the appropriate profile flag and optional command-line parameter overrides (e.g., --max_cpus for resource allocation, not --cpus), directing logs to a designated output folder.

Related tools

• Nextflow (Workflow orchestration and execution engine managing task distribution, containerization, and logging across execution environments) — https://www.nextflow.io/
• MS-DIAL (Containerized peak detection and chromatogram alignment tool; parameters defined in msdial_params.txt)
• MSFLO (Containerized feature quantification and metabolite identification tool; parameters defined in msflo_params.ini)
• Docker (Container backend for local execution of MS-DIAL and MSFLO; configured in conf/base.config) — https://docs.docker.com/engine/installation/
• Singularity (Container backend for HPC environments; configured in conf/HiPerGator.config for Slurm-based systems) — https://www.sylabs.io/guides/3.0/user-guide/
• Java (Runtime environment required for Nextflow execution (version 11.0.8 or later))

Examples

nextflow run main.nf -profile docker > logs/execution.log

Evaluation signals

• Execution log (logs/execution.log) records successful Nextflow and workflow version metadata, parameter settings, and absence of configuration-related errors.
• Execution report (execution_report.html) shows all pipeline stages completed without error and resource allocation matches CPU/memory requests in configuration.
• Output directory contains expected .tsv feature tables and aligned data matrices with correct naming and non-zero file sizes.
• Log file does not contain 'Process requirement exceed available CPUs' or file-name-related errors; file names in input directory use only safe characters (underscores, alphanumerics).
• Container information in execution log confirms the correct backend (Docker or Singularity) was invoked and container images were successfully pulled/cached.

Limitations

• Special characters in input file names cause unexpected errors; only underscores and alphanumerics are safe.
• MS-DIAL and MS-FLO version information is not specified in configuration files, limiting reproducibility and version-specific debugging; users must track tool versions manually.
• Slurm job allocation confusion: the --max_cpus parameter defines per-process CPU limits in the configuration, not total job CPUs; using --cpus instead causes allocation failures.
• The workflow has been tested only on macOS 13.5.1 (Intel Core i7, 16 GB memory) and Red Hat Enterprise Linux 8.8 (HiPerGator); compatibility with other OS versions or HPC schedulers is not documented.
• No explicit reproducibility validation or testing protocol is provided in the initial release; users must manually verify results against example outputs.

Evidence

• [readme] Add the MS-DIAL and MS-FLO configuration files to the data/ folder and name them msdial_params.txt and msflo_params.ini.: "Add the MS-DIAL and MS-FLO configuration files to the data/ folder and name them msdial_params.txt and msflo_params.ini."
• [readme] Add the MS1 and MS2 libraries to the data/ folder and name them ms1_lib.txt and ms2_lib.msp.: "Add the MS1 and MS2 libraries to the data/ folder and name them ms1_lib.txt and ms2_lib.msp."
• [readme] Before processing your own data, confirm that the reference file in conf/base.config and the MS-DIAL configuration file are set correctly.: "Before processing your own data, confirm that the reference file in conf/base.config and the MS-DIAL configuration file are set correctly."
• [readme] Docker configuration is defined in conf/base.config. High-performance computing and Singularity configuration is defined in conf/HiPerGator.config.: "Docker configuration is defined in conf/base.config. High-performance computing and Singularity configuration is defined in conf/HiPerGator.config."
• [readme] The workflow includes Docker and Singularity support to simplify installation, improve portability, and make results easier to reproduce.: "The workflow includes Docker and Singularity support to simplify installation, improve portability, and make results easier to reproduce."
• [readme] To avoid unexpected errors, do not use special characters in file names. Underscores are safe to use.: "To avoid unexpected errors, do not use special characters in file names. Underscores are safe to use."
• [readme] Use --max_cpus, not --cpus, in the configuration file to define the CPUs available to each process.: "Use --max_cpus, not --cpus, in the configuration file to define the CPUs available to each process."
• [other] Configure the workflow parameters (sample input path, output directory, Docker backend specification) in the Nextflow config or command-line arguments.: "Configure the workflow parameters (sample input path, output directory, Docker backend specification) in the Nextflow config or command-line arguments."