Environment Variables

Splinter honors a small number of environment variables. They affect both library (API) use and the CLI tools, since the CLI creates and addresses stores through the same library calls.

SPLINTER_DEFAULT_UMASK

Controls the file permissions of newly created stores. This affects both API and CLI use.

A new store — the POSIX shared-memory object in the default build, or the backing file in persistent mode — is created with mode 0666 masked by the process umask. By default that means it inherits the shell's umask, which on most GNU systems (umask 022) leaves the store readable by other local users (0644). For a shared-memory substrate this can be an unwelcome surprise.

Splinter deliberately does not change that default, because the common case is local and/or automated use that may already rely on the inherited umask. Instead, set SPLINTER_DEFAULT_UMASK to an octal umask value to override the permissions at creation time only:

# CLI: create a private store
SPLINTER_DEFAULT_UMASK=077 splinterctl init mystore

# API: same effect, applied around splinter_create()
SPLINTER_DEFAULT_UMASK=077 ./my_program

Notes and limits:

• It is applied as the process umask only for the duration of store creation, then the previous umask is restored.
• It takes effect only when a store is created. It does not change the permissions of a store that already exists — use chmod (or the usual tools) to adjust those afterward.
• An unset, empty, or unparseable value is ignored, and creation falls back to the inherited umask. The value must be a valid octal mask in the range 0–0777.
• Applies to persistent mode as well as the default shared-memory mode.

See splinter_create (API) and init (CLI) for the creation paths this governs.

SPLINTER_NS_PREFIX

Prepends a namespace prefix to keys in the CLI's key-addressed commands (get, set, head, append, unset, bump, retrain, watch, type, and others). When set, the prefix is prepended to the key name before the operation, so a value of tenantA: turns get widget into a read of tenantA:widget.

It can also be set for the current splinterctl / splinter_cli session with the --prefix / -p program option, which exports it into the environment.

SPLINTER_NS_PREFIX="tenantA:" splinterctl get widget   # reads tenantA:widget
splinterctl --prefix "tenantA:" get widget             # equivalent

This is a CLI-side convenience; the library's own functions take whole key strings as given.