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Configure dsprrr Cache

Source: R/cache.R
configure_cache.Rd

Configure the caching behavior for LLM responses. By default, both memory and disk caching are enabled.

Usage

configure_cache(
  enable = TRUE,
  enable_memory = TRUE,
  enable_disk = TRUE,
  disk_path = default_disk_cache_path(),
  disk_private = TRUE,
  memory_max_entries = 1000L,
  disk_max_size = 500 * 1024^2,
  disk_max_age = Inf
)

Arguments

enable

Logical. Master switch to enable/disable all caching. Default TRUE.

enable_memory

Logical. Enable in-memory LRU cache. Default TRUE.

enable_disk

Logical. Enable persistent disk cache. Default TRUE.

disk_path

Character. Path for disk cache directory. Defaults to tools::R_user_dir("dsprrr", "cache"), unless overridden by DSPRRR_CACHE_PATH.

disk_private

Logical. Enforce private cache storage. On Unix, require effective ownership and private POSIX modes for the directory and response files. On Windows, use inherited ACLs and report privacy as unverified. Set to FALSE only for an explicitly trusted shared cache. Default TRUE.

memory_max_entries

Integer. Maximum entries in memory cache. Default 1000L.

disk_max_size

Numeric. Maximum disk cache size in bytes. Default 500 * 1024^2 (500MB).

disk_max_age

Numeric. Maximum age in seconds for disk cache entries. Default Inf (no age limit).

Value

Invisibly returns the previous cache configuration as a list.

Details

The cache stores versioned envelopes containing parsed LLM responses and, when needed, semantic conversation-turn deltas used to restore an ellmer Chat after a cache hit. Although cache keys hash request identity, envelope values may contain raw request content and model outputs. Treat persistent cache files as sensitive data.

Disk privacy: By default, the disk cache uses the platform-specific per-user cache directory. On Unix, dsprrr verifies effective ownership, canonical path identity, a 0700 cache directory, and 0600 response files before serialized reads and writes. Unsafe disk caches fall back to memory when enabled; otherwise no cache tier remains active. On Windows, the per-user directory inherits the account's filesystem ACLs; base R cannot verify that those ACLs are owner-only. Set disk_private = FALSE only for a cache whose writers and readers are all trusted.

Existing Unix caches that were readable but not writable by other accounts are tightened before reuse. Caches that were writable by another account, contain symbolic links or non-regular filesystem entries, or cannot be verified are not read; dsprrr uses memory caching when enabled and otherwise runs uncached. A shared writable cache could replace an RDS response envelope and must be treated as untrusted serialized input.

POSIX modes cannot describe every filesystem policy. dsprrr does not inspect extended ACLs, administrators can still access owner files, and some network filesystems do not honor local mode changes. A same-account process can also race path checks and file opens; dsprrr checks identity before and after I/O but base R does not expose descriptor-level openat()/fstat() guarantees. Avoid shared or network cache paths for sensitive workloads. In CI, disable caching with DSPRRR_CACHE_ENABLED=false or use a job-specific DSPRRR_CACHE_PATH.

Environment variable: Set DSPRRR_CACHE_ENABLED=false (or 0, no, off) to globally disable caching, useful for CI/testing environments.

Git: The default cache is outside the project. If you explicitly use a project-local path, add it to .gitignore, for example:

# dsprrr LLM response cache
.dsprrr_cache/

Examples

if (FALSE) { # \dontrun{
# Use defaults (caching enabled)
configure_cache()

# Disable disk cache (memory only)
configure_cache(enable_disk = FALSE)

# Disable all caching
configure_cache(enable = FALSE)

# Custom disk location and size
configure_cache(
  disk_path = "~/.dsprrr_cache",
  disk_max_size = 1024^3  # 1GB
)

# Trusted shared caches require an explicit privacy opt-out
configure_cache(
  disk_path = "/srv/trusted-team/dsprrr-cache",
  disk_private = FALSE
)
} # }