Files
hickory-dns/crates/resolver/examples/multithreaded_runtime.rs
2019-10-17 21:59:20 -07:00

66 lines
2.3 KiB
Rust

#![recursion_limit = "128"]
//! This example shows how to create a resolver that uses the tokio multithreaded runtime. This is how
//! you might integrate the resolver into a more complex application.
extern crate env_logger;
extern crate futures;
extern crate tokio;
extern crate trust_dns_resolver;
use tokio::runtime::Runtime;
use trust_dns_resolver::AsyncResolver;
fn main() {
env_logger::init();
// Set up the standard tokio runtime (multithreaded by default).
let runtime = Runtime::new().expect("Failed to create runtime");
let (resolver, bg) = {
// To make this independent, if targeting macOS, BSD, Linux, or Windows, we can use the system's configuration:
#[cfg(any(unix, windows))]
{
// use the system resolver configuration
AsyncResolver::from_system_conf().expect("Failed to create AsyncResolver")
}
// For other operating systems, we can use one of the preconfigured definitions
#[cfg(not(any(unix, windows)))]
{
// Directly reference the config types
use trust_dns_resolver::config::{ResolverConfig, ResolverOpts};
// Get a new resolver with the google nameservers as the upstream recursive resolvers
AsyncResolver::new(ResolverConfig::google(), ResolverOpts::default())
}
};
// The resolver background task needs to be created in the runtime so it can
// connect to the reactor.
runtime.spawn(bg);
// Create some futures representing name lookups.
let names = &["www.google.com", "www.reddit.com", "www.wikipedia.org"];
let mut futures = names
.iter()
.map(|name| (name, resolver.lookup_ip(*name)))
.collect::<Vec<_>>();
// Go through the list of resolution operations and wait for them to complete.
for (name, lookup) in futures.drain(..) {
let ips = runtime
.block_on(lookup)
.expect("Failed completing lookup future")
.iter()
.collect::<Vec<_>>();
println!("{} resolved to {:?}", name, ips);
}
// Drop the resolver, which means that the runtime will become idle.
drop(resolver);
// Once we have finished using the runtime, we can ask it to shut down when it's done (this blocks).
runtime.shutdown_on_idle();
}