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Environment Variables

FZ can be configured using several environment variables to customize its behavior.

Core Configuration

FZ_LOG_LEVEL

Description: Controls the verbosity of FZ logging output.

Values: DEBUG, INFO, WARNING, ERROR, CRITICAL

Default: INFO

Example: 

export FZ_LOG_LEVEL=DEBUG

FZ_INTERPRETER

Description: Default formula interpreter for evaluating expressions.

Values: python, R

Default: python

Example: 

export FZ_INTERPRETER=R

Execution Configuration

FZ_EXECUTION_TIMEOUT

Description: Default timeout in seconds for calculator execution. Can be overridden by model configuration or calculator URI parameters.

Values: Positive integer (seconds)

Default: None (no timeout)

Example: 

export FZ_EXECUTION_TIMEOUT=300  # 5 minutes

FZ_MAX_RETRIES

Description: Maximum number of retry attempts when a calculator fails.

Values: Non-negative integer

Default: 3

Example: 

export FZ_MAX_RETRIES=5

FZ_MAX_WORKERS

Description: Maximum number of parallel workers for concurrent execution.

Values: Positive integer

Default: Number of CPU cores

Example: 

export FZ_MAX_WORKERS=8

Shell Configuration

FZ_SHELL_PATH (New in 0.9.1)

Description: Custom search path for shell commands and executables. Overrides system PATH for binary resolution. Essential for Windows users with MSYS2, Git Bash, or custom tool locations.

Format: - Windows: Semicolon-separated paths - Unix/Linux: Colon-separated paths

Default: System PATH

Example: 

# Windows
SET FZ_SHELL_PATH=C:\msys64\usr\bin;C:\msys64\mingw64\bin;C:\Python39

# Linux/macOS
export FZ_SHELL_PATH=/opt/tools/bin:/usr/local/bin

Features: - Automatic .exe extension handling on Windows - Binary path caching for performance - Overrides system PATH priority

SSH Configuration

FZ_SSH_KEEPALIVE

Description: Interval in seconds for SSH keepalive packets to prevent connection timeout.

Values: Positive integer (seconds)

Default: 60

Example: 

export FZ_SSH_KEEPALIVE=30

Cache Configuration

FZ_CACHE_DIR

Description: Directory for storing cached results.

Values: Valid directory path

Default: .fz/cache in working directory

Example: 

export FZ_CACHE_DIR=/tmp/fz_cache

Discovery Configuration

FZ_UDP_DISCOVERY_PORT

Description: UDP port for Funz calculator auto-discovery.

Values: Valid port number

Default: 21001

Example: 

export FZ_UDP_DISCOVERY_PORT=21001

Configuration Files

Model and Calculator Aliases

FZ looks for configuration files in:

  • Models: ~/.fz/models/ and ./.fz/models/
  • Calculators: ~/.fz/calculators/ and ./.fz/calculators/

Configuration files use JSON format:

Model Example (~/.fz/models/perfectgas.json): 

{
  "varprefix": "$",
  "interpreter": "python",
  "output": {
    "pressure": "grep 'P =' output.txt | awk '{print $3}'"
  }
}

Calculator Example (~/.fz/calculators/compute.json): 

{
  "uri": "ssh://user@cluster.example.edu/bash",
  "models": ["perfectgas", "simulation"]
}

Platform-Specific Notes

Windows

  • Use SET instead of export for environment variables
  • Path separators are semicolons (;) in FZ_SHELL_PATH
  • Consider setting FZ_SHELL_PATH for Git Bash or MSYS2 tools

Linux/macOS

  • Use export for environment variables
  • Path separators are colons (:) in FZ_SHELL_PATH
  • Environment variables can be set in ~/.bashrc or ~/.zshrc

See Also