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use anyhow::{anyhow, bail, Context, Result};
use crimp::Request;
use std::env;
use std::net::Ipv4Addr;
use tokio::runtime;
use yandex_cloud::tonic_exports::{Channel, Endpoint, InterceptedService};
use yandex_cloud::yandex::cloud::dns::v1 as dns;
use yandex_cloud::yandex::cloud::dns::v1::dns_zone_service_client::DnsZoneServiceClient;
use yandex_cloud::{AuthInterceptor, TokenProvider};
type DnsClient<T> = DnsZoneServiceClient<InterceptedService<Channel, AuthInterceptor<T>>>;
/// Fetch the current IP from the given URL. It should be the URL of a
/// site that responds only with the IP in plain text, and nothing else.
fn get_current_ip(source: &str) -> Result<Ipv4Addr> {
let response = Request::get(source)
.send()
.context("failed to fetch current IP")?
.error_for_status(|resp| anyhow!("error response ({})", resp.status))
.context("received error response for IP")?
.as_string()?
.body;
Ok(response.trim().parse().with_context(|| {
format!(
"failed to parse IP address from response body: {}",
response
)
})?)
}
/// Fetch the current address of the target record.
async fn fetch_current_record_addr<T: TokenProvider>(
client: &mut DnsClient<T>,
zone_id: &str,
record_name: &str,
) -> Result<Ipv4Addr> {
let req = dns::GetDnsZoneRecordSetRequest {
dns_zone_id: zone_id.into(),
name: record_name.into(),
r#type: "A".into(),
};
let response = client
.get_record_set(req)
.await
.context("failed to fetch current record set")?
.into_inner();
if response.data.len() != 1 {
bail!(
"expected exactly one record for 'A {}', but found {}",
record_name,
response.data.len()
);
}
Ok(response.data[0]
.parse()
.context("failed to parse returned record")?)
}
/// Update the record with the new address, if required.
async fn update_record<T: TokenProvider>(
client: &mut DnsClient<T>,
zone_id: &str,
record_name: &str,
new_address: Ipv4Addr,
) -> Result<()> {
let request = dns::UpsertRecordSetsRequest {
dns_zone_id: zone_id.into(),
replacements: vec![dns::RecordSet {
name: record_name.into(),
r#type: "A".into(),
ttl: 3600, // 1 hour
data: vec![new_address.to_string()],
}],
..Default::default()
};
client
.upsert_record_sets(request)
.await
.context("failed to update record")?;
Ok(())
}
/// Compare the record with the expected value, and issue an update if
/// necessary.
async fn compare_update_record<T: TokenProvider>(
client: &mut DnsClient<T>,
zone_id: &str,
record_name: &str,
new_ip: Ipv4Addr,
) -> Result<()> {
let old_ip = fetch_current_record_addr(client, zone_id, record_name).await?;
if old_ip == new_ip {
println!("IP address unchanged ({})", old_ip);
return Ok(());
}
println!(
"IP address changed: current record points to {}, but address is {}",
old_ip, new_ip
);
update_record(client, zone_id, record_name, new_ip).await?;
println!("successfully updated '{}' to 'A {}'", record_name, new_ip);
Ok(())
}
fn main() -> Result<()> {
let token =
env::var("YANDEX_CLOUD_TOKEN").context("Yandex Cloud authentication token unset")?;
let target_zone_id =
env::var("TARGET_ZONE").unwrap_or_else(|_| "dnsd0tif5mokfu0mg8i5".to_string());
let target_record = env::var("TARGET_RECORD").unwrap_or_else(|_| "khtrsk".to_string());
let current_ip = get_current_ip("http://ifconfig.me")?;
println!("current IP address is '{}'", current_ip);
let rt = runtime::Builder::new_current_thread()
.enable_time()
.enable_io()
.build()?;
rt.block_on(async move {
let channel = Endpoint::from_static("https://dns.api.cloud.yandex.net")
.connect()
.await?;
let mut client =
DnsZoneServiceClient::with_interceptor(channel, AuthInterceptor::new(token));
compare_update_record(&mut client, &target_zone_id, &target_record, current_ip).await
})?;
Ok(())
}
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