Configuration

Configuration#

The package reads its configuration from environment variables, once per process, when a cached function is first called. It has no control panel and no registry records. Changing a variable requires restarting the instance.

An unset or empty variable takes its default. An invalid value raises ValueError, naming the variable, and the instance does not start.

Environment variables#

Variable

Default

Accepts

REDIS_MEMOIZE_URL

unset

A URL with the scheme redis, rediss, or unix. Unset, the package is inert.

REDIS_MEMOIZE_PREFIX

plone.memoize

Text without spaces. Every key starts with it.

REDIS_MEMOIZE_TTL

86400

An integer of at least 1, in seconds. The lifetime of a value in Redis.

REDIS_MEMOIZE_TIMEOUT

0.25

A number of at least 0.001, in seconds. The connect and read timeout.

REDIS_MEMOIZE_RETRY_AFTER

30

A number of at least 0, in seconds. How long an instance leaves Redis alone after a failure.

REDIS_MEMOIZE_MAX_SIZE

1048576

An integer of at least 1, in bytes. Larger serialized values stay in RAM.

REDIS_MEMOIZE_INCLUDE

empty

Comma-separated fnmatch patterns of function names. When set, only matching functions use Redis.

REDIS_MEMOIZE_EXCLUDE

empty

Comma-separated fnmatch patterns of function names. Matching functions stay in RAM; exclusion wins over inclusion.

The test suite parses this table and compares it with the code.

Keys#

Each value is stored under a key made of three parts, separated by colons:

<prefix>:<function>:<hash>

prefix

REDIS_MEMOIZE_PREFIX.

function

The dotted name of the cached function, such as plone.app.layout.sitemap.sitemap.generate.

hash

The SHA-1 of the key plone.memoize computed for the call.

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