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Config & runtime paths

Config discovery​

Prism can find a config file automatically, or you can specify one explicitly.

Explicit config​

  • CLI flag: --config /path/to/prism.toml
  • Environment: PRISM_CONFIG=/path/to/prism.toml

Auto-discovery​

From the current working directory, Prism checks (in order):

  1. prism.toml
  2. prism.yaml
  3. prism.yml

Fallback default path​

If no config is provided and no file is discovered, Prism falls back to:

  • Linux: /etc/prism/prism.toml
  • Other OSes: ${ProjectConfigDir}/prism.toml (derived from Rust’s directories::ProjectDirs)

If the resolved config path does not exist, Prism will create a runnable default config file at that path and continue starting.

Work directory​

Prism uses a work directory for runtime state.

  • CLI flag: --workdir /path/to/workdir
  • Environment: PRISM_WORKDIR=/path/to/workdir
  • Default:
    • Linux: /var/lib/prism
    • Other OSes: per-user data dir (from directories::ProjectDirs)

Routing parsers directory​

Routing parsers are .wat files (WebAssembly text format) used to extract a hostname from the first bytes of a TCP stream.

  • CLI flag: --routing-parser-dir /path/to/parsers
  • Environment: PRISM_ROUTING_PARSER_DIR=/path/to/parsers
  • Default: <config_dir>/parsers (Linux default: /etc/prism/parsers)

Relative paths​

If you pass a relative --routing-parser-dir (or env var), it is resolved relative to the config directory (the directory containing the resolved config file).

This makes it easy to keep everything together:

/etc/prism/prism.toml
/etc/prism/parsers/