Struct State 

pub struct State<'a> { /* private fields */ }

Implementations

impl<'a> State<'a>

pub fn new(manifest_dir: &str, load: Load<'a>) -> Self

Creates a new State with the given manifest directory and load handler.

Examples

use state_engine::State;
use state_engine::load::Load;

let state = State::new("./examples/manifest", Load::new());

pub fn with_in_memory(self, client: &'a mut dyn InMemoryClient) -> Self

pub fn with_kvs_client(self, client: &'a mut dyn KVSClient) -> Self

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

Returns the value for key, checking state cache → _store → _load in order.

Examples

use state_engine::State;
use state_engine::load::Load;
use state_engine::InMemoryClient;
use serde_json::{json, Value};

struct MockInMemory { data: std::collections::HashMap<String, Value> }
impl MockInMemory { fn new() -> Self { Self { data: Default::default() } } }
impl InMemoryClient for MockInMemory {
    fn get(&self, key: &str) -> Option<Value> { self.data.get(key).cloned() }
    fn set(&mut self, key: &str, value: Value) { self.data.insert(key.to_string(), value); }
    fn delete(&mut self, key: &str) -> bool { self.data.remove(key).is_some() }
}

let mut client = MockInMemory::new();
let mut state = State::new("./examples/manifest", Load::new())
    .with_in_memory(&mut client);

// set then get
state.set("connection.common", json!({"host": "localhost"}), None).unwrap();
assert!(state.get("connection.common").unwrap().is_some());

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

Writes value to the _store backend for key.

Examples

let mut client = MockInMemory::new();
let mut state = State::new("./examples/manifest", Load::new())
    .with_in_memory(&mut client);

assert!(state.set("connection.common", json!({"host": "localhost"}), None).unwrap());

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

Removes the value for key from the _store backend.

Examples

let mut client = MockInMemory::new();
let mut state = State::new("./examples/manifest", Load::new())
    .with_in_memory(&mut client);

state.set("connection.common", json!({"host": "localhost"}), None).unwrap();
assert!(state.delete("connection.common").unwrap());
// delete後はstoreにデータがなく、_loadも試みるが今回はEnvClientなしのため値なし
assert!(state.get("connection.common").is_err() || state.get("connection.common").unwrap().is_none());

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

Returns true if a value exists for key in state cache or _store. Does not trigger _load.

Examples

let mut client = MockInMemory::new();
let mut state = State::new("./examples/manifest", Load::new())
    .with_in_memory(&mut client);

assert!(!state.exists("connection.common").unwrap());
state.set("connection.common", json!({"host": "localhost"}), None).unwrap();
assert!(state.exists("connection.common").unwrap());