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use std::collections::HashMap;
use std::fmt::Debug;
use std::sync::Arc;
use std::time::Duration;
use abstract_ns::{Name, Address, IpList};
use abstract_ns::{HostResolve, Resolve, HostSubscribe, Subscribe};
use internal_traits::{Resolver, Wrapper, NullResolver};
/// Configuration of the router
///
/// It has a builder interface. You can create a router from `Arc<Config>`
/// (made by `Config::done`) or a stream of configs.
#[derive(Clone, Debug)]
pub struct Config {
pub(crate) restart_delay: Duration,
pub(crate) convergence_delay: Duration,
pub(crate) hosts: HashMap<Name, IpList>,
pub(crate) services: HashMap<Name, Address>,
pub(crate) suffixes: HashMap<String, Arc<Resolver>>,
pub(crate) root: Arc<Resolver>,
}
impl Config {
/// Create a new, empty config
pub fn new() -> Config {
Config {
restart_delay: Duration::from_millis(100),
convergence_delay: Duration::from_millis(100),
hosts: HashMap::new(),
services: HashMap::new(),
suffixes: HashMap::new(),
root: Arc::new(NullResolver),
}
}
/// Sets delay after which router will restart any subscription stream
///
/// This works both when stream yields end-of-stream and when stream
/// has returned error. Default value is 100 milliseconds.
pub fn restart_delay(&mut self, delay: Duration) -> &mut Self {
self.restart_delay = delay;
self
}
/// Sets delay used by [`subscribe_many`] family of functions
///
/// The timeout is set when a new set of names arrives via stream or
/// when configuration is updated. While the timer is active we don't
/// send name updates to the application unless all (new) names are
/// resolved.
///
/// Good value is bigger than 90 or 99 percentile of name request
/// latency, but small enough that delay of this long doesn't introduce
/// any hiccups on the application.
///
/// For example, if there are names [A, B, C] if C is resolved first
/// we wait for the 100 millisecond (by default) timer to finish
/// to let A and B also be resolved. If they aren't within the period
/// only names in `C` are returned.
///
/// Note if names are reloved later, they are added to the address set
/// and update is delivered to the client. I.e. it's only important
/// something depends on the first address value.
///
/// The case where it's important is following: Client establishes
/// few persistent connections by picking random IP Addresses from the
/// set. Once new addresses arrive connections are still hold until
/// one of them is broken. In this case, the first address (or the
/// one that can be resolved faster for any reason) would have more
/// connections received in most cases which might be a problem.
///
/// [`subscribe_many`]: struct.Router.html#tymethod.subscribe_many
pub fn convergence_delay(&mut self, delay: Duration) -> &mut Self {
self.convergence_delay = delay;
self
}
/// Add a host that will be resolved to list of addreses
///
/// Hosts added by this host method overrides any other resolvers.
pub fn add_host<A>(&mut self, name: &Name, addr: A)
-> &mut Self
where A: Into<IpList>
{
self.hosts.insert(name.clone(), addr.into());
self
}
/// Add a service that will be resolved to an Address object
///
/// Service names added by this host method overrides any other resolvers.
pub fn add_service(&mut self, name: &Name, addr: Address) -> &mut Self {
self.services.insert(name.clone(), addr);
self
}
/// Add a resolver for suffix
///
/// Note: you must supply a full resolver here,
/// use `null_resolver`/`null_host_resolver` and
/// [`interval_subscribe`] or `frozen_subscriber`
/// and other combinators to fullfill needed type.
///
/// [`interval_subscribe`]: trait.SubscribeExt.html#tymethod.interval_subscribe
pub fn add_suffix<S, R>(&mut self, suffix: S, resolver: R)
-> &mut Self
where S: Into<String>,
R: Resolve + HostResolve + Subscribe + HostSubscribe,
R: Debug + 'static,
{
self.suffixes.insert(suffix.into(),
Arc::new(Wrapper::new(resolver)));
self
}
/// Removes already configured suffix
pub fn remove_suffix<S>(&mut self, suffix: &str)
-> &mut Self
{
self.suffixes.remove(suffix);
self
}
/// Adds a host resolver used whenever no suffix matches
pub fn set_fallthrough<R>(&mut self, resolver: R)
-> &mut Self
where R: Resolve + HostResolve + Subscribe + HostSubscribe,
R: Debug + 'static,
{
self.root = Arc::new(Wrapper::new(resolver));
self
}
/// A convenience method that returns Arc'd config
pub fn done(&self) -> Arc<Config> {
Arc::new(self.clone())
}
}