Struct pingora_load_balancing::Backends

pub struct Backends { /* private fields */ }

Backends is a collection of Backends.

It includes a service discovery method (static or dynamic) to discover all the available backends as well as an optionally health check method to probe the liveness of each backend.

Implementations

impl Backends

pub fn new(discovery: Box<dyn ServiceDiscovery + Send + Sync + 'static>) -> Self

Create a new Backends with the given ServiceDiscovery implementation.

The health check method is by default empty.

pub fn set_health_check( &mut self, hc: Box<dyn HealthCheck + Send + Sync + 'static> )

Set the health check method. See health_check for the methods provided.

pub fn ready(&self, backend: &Backend) -> bool

Whether a certain Backend is ready to serve traffic.

This function returns true when the backend is both healthy and enabled. This function returns true when the health check is unset but the backend is enabled. When the health check is set, this function will return false for the backend it doesn’t know.

pub fn set_enable(&self, backend: &Backend, enabled: bool)

Manually set if a Backend is ready to serve traffic.

This method does not override the health of the backend. It is meant to be used to stop a backend from accepting traffic when it is still healthy.

This method is noop when the given backend doesn’t exist in the service discovery.

pub fn get_backend(&self) -> Arc<BTreeSet<Backend>>

Return the collection of the backends.

pub async fn update(&self) -> Result<bool>

Call the service discovery method to update the collection of backends.

Return true when the new collection is different from the current set of backends. This return value is useful to tell the caller when to rebuild things that are expensive to update, such as consistent hashing rings.

pub async fn run_health_check(&self, parallel: bool)

Run health check on all the backend if it is set.

When parallel: true, all the backends are checked in parallel instead of sequentially