GT-post - Postprocessing of Delft3D-Geotool models

Overview

GT-Post provides preprocessing and postprocessing tools for Delft3D-Geotool simulation models. It runs as a containerized service that can be orchestrated by Radix.

Container Entrypoint

The container uses entrypoint.sh to coordinate job execution. It supports three job modes controlled by the JOB_MODE environment variable.

Job Modes

Mode	Description	Input	Output
preprocess	Generates Delft3D input files from templates	Payload JSON with ini_parameters	main_dir/orch-{id}/preprocess/
process	Runs during simulation (incremental processing)	main_dir/orch-{id}/simulation/	Same directory (in-place)
postprocess	Runs after simulation completes	main_dir/orch-{id}/simulation/	Same directory (in-place)

Environment Variables

Variable	Default	Description
JOB_MODE	postprocess	Job mode: preprocess, process, or postprocess
WORK_DIR	./tmp/work	Temporary working directory
MAIN_DIR	./tmp/main	Final storage location for artifacts
ARGS_FOLDER	./tmp/args	Directory containing the payload JSON file

Payload Format

The entrypoint expects a JSON payload file at ${ARGS_FOLDER}/payload:

{
  "orchestration_id": "S123",
  "run_id": "R001",
  "ini_parameters": {
    "template": { "value": "River_dominated_delta" },
    "basinslope": { "value": 0.04 },
    "simstoptime": { "value": 320.5 }
  }
}

• orchestration_id (or orchestrationId) — used to build folder paths
• run_id (or runId) — used for preprocess work directory naming
• ini_parameters (or iniParameters) — converted to input.ini for preprocessing

Directory Structure

After running jobs, the following structure is created:

main_dir/
└── orch-{orchestration_id}/
    ├── preprocess/
    │   ├── input/      # Input files (including input.ini)
    │   └── output/     # Generated Delft3D files
    └── simulation/     # Simulation output (used by process/postprocess)

Docker Usage

# Build the image
docker build -t gtpost:latest .

# Run preprocess
docker run --rm \
  -e JOB_MODE=preprocess \
  -e WORK_DIR=/tmp/work \
  -e MAIN_DIR=/tmp/main \
  -e ARGS_FOLDER=/args \
  -v ./work:/tmp/work \
  -v ./main:/tmp/main \
  -v ./args:/args:ro \
  gtpost:latest

# Run postprocess (after simulation has written to main_dir/orch-{id}/simulation/)
docker run --rm \
  -e JOB_MODE=postprocess \
  -e MAIN_DIR=/tmp/main \
  -e ARGS_FOLDER=/args \
  -v ./main:/tmp/main \
  -v ./args:/args:ro \
  gtpost:latest

Exit Codes

Code	Description
0	Success
2	Failed to extract IDs from payload
3	Payload handler failed
4	Failed to copy input artifacts
5	Failed to copy output artifacts
6	Process mode missing orchestration_id
7	Postprocess mode missing orchestration_id
8	Unknown JOB_MODE

CI/CD

This repository uses GitHub Actions for CI and container image publishing. See docs/ci-cd.md for full details (tests, release-please integration, and the reusable build-and-publish workflow).