Struct 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 optional 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<F>(&self, callback: F) -> Result<()>

where F: Fn(Arc<BTreeSet<Backend>>),

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

The callback will be invoked when the new set of backend is different from the current one so that the caller can update the selector accordingly.

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

Run health check on all backends if it is set.

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