Struct Cache 

pub struct Cache { /* private fields */ }

A connected cache, shared by every worker.

Cloning is cheap: the underlying redis::aio::ConnectionManager is reference-counted and reconnects on its own, so a clone shares one connection rather than opening another.

Implementations

impl Cache

pub async fn connect(config: &CacheConfig) -> Result<Option<Cache>, CacheError>

Connect the cache an app’s [cache] section describes.

Ok(None) means the app configured none, which is the default and not an error. Err means it asked for one that can’t be reached — worth failing the boot over, because a function written against a cache and silently given none is a bug that only shows up as a load spike.

pub async fn execute(&self, request: &str) -> Result<Value, CacheError>

Run one operation, given as the JSON a function sent across the ABI, and return the JSON reply.

This is the single entry point the host bridge uses, which is what keeps the ABI to one cache call instead of one per verb — a new operation costs a variant of Op, not a change to the contract every compiled function was built against.

pub async fn get(&self, key: &str) -> Result<Option<Value>, CacheError>

Read a value, or None when the key is absent or expired.

A value that isn’t valid JSON (something else wrote it) comes back as a JSON string rather than as an error — the caller asked for whatever is there.

pub async fn set( &self, key: &str, value: &Value, ttl: Option<u64>, ) -> Result<(), CacheError>

Write a value. ttl of None uses [cache] default_ttl_secs; 0 means “no expiry” in both places.

pub async fn delete(&self, key: &str) -> Result<bool, CacheError>

Remove a key. true when it was there.

pub async fn exists(&self, key: &str) -> Result<bool, CacheError>

Whether a key is present and unexpired.

pub async fn incr( &self, key: &str, by: i64, ttl: Option<u64>, ) -> Result<i64, CacheError>

Add to a counter and return its new value, creating it at zero first.

Atomic on the server, which is what makes it usable for rate limiting from several workers (or several hosts) at once — a read-modify-write through get and set would not be.

pub async fn ttl(&self, key: &str) -> Result<Option<i64>, CacheError>

Seconds until a key expires: None when it is absent or has no expiry.

Trait Implementations

impl Clone for Cache

fn clone(&self) -> Cache

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Cache

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.