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use std::collections::{HashMap, HashSet};
use std::fmt;
use std::sync::Arc;
use std::time::Duration;
use tokio::{select, sync::watch};
use tracing::*;
use df_consul::*;
const IPV4_TARGET_METADATA_TAG: &str = "public_ipv4";
const IPV6_TARGET_METADATA_TAG: &str = "public_ipv6";
const CNAME_TARGET_METADATA_TAG: &str = "cname_target";
// ---- Extract DNS config from Consul catalog ----
#[derive(Debug, Eq, PartialEq, Default)]
pub struct DnsConfig {
pub entries: HashMap<DnsEntryKey, DnsEntryValue>,
}
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub struct DnsEntryKey {
pub dns_path: String,
pub record_type: DnsRecordType,
}
#[derive(Debug, PartialEq, Eq)]
pub struct DnsEntryValue {
pub targets: HashSet<String>,
}
#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq)]
#[allow(clippy::upper_case_acronyms)]
pub enum DnsRecordType {
A,
AAAA,
CNAME,
}
impl DnsConfig {
pub fn new() -> Self {
Self {
entries: HashMap::new(),
}
}
fn add(&mut self, k: DnsEntryKey, v: DnsEntryValue) {
if let Some(ent) = self.entries.get_mut(&k) {
ent.targets.extend(v.targets);
} else {
self.entries.insert(k, v);
}
}
}
fn parse_d53_tag(tag: &str, node: &catalog::Node) -> Option<(DnsEntryKey, DnsEntryValue)> {
let splits = tag.split(' ').collect::<Vec<_>>();
if splits.len() != 2 {
return None;
}
let (record_type, targets) = match splits[0] {
"d53-a" => match node.meta.get(IPV4_TARGET_METADATA_TAG) {
Some(tgt) => (DnsRecordType::A, [tgt.to_string()].into_iter().collect()),
None => {
warn!("Got d53-a tag `{}` but node {} does not have a {} metadata value. Tag is ignored.", tag, node.node, IPV4_TARGET_METADATA_TAG);
return None;
}
},
"d53-aaaa" => match node.meta.get(IPV6_TARGET_METADATA_TAG) {
Some(tgt) => (DnsRecordType::AAAA, [tgt.to_string()].into_iter().collect()),
None => {
warn!("Got d53-aaaa tag `{}` but node {} does not have a {} metadata value. Tag is ignored.", tag, node.node, IPV6_TARGET_METADATA_TAG);
return None;
}
},
"d53-cname" => match node.meta.get(CNAME_TARGET_METADATA_TAG) {
Some(tgt) => (
DnsRecordType::CNAME,
[tgt.to_string()].into_iter().collect(),
),
None => {
warn!("Got d53-cname tag `{}` but node {} does not have a {} metadata value. Tag is ignored.", tag, node.node, CNAME_TARGET_METADATA_TAG);
return None;
}
},
_ => return None,
};
Some((
DnsEntryKey {
dns_path: splits[1].to_string(),
record_type,
},
DnsEntryValue { targets },
))
}
pub fn spawn_dns_config_task(
consul: &Consul,
mut must_exit: watch::Receiver<bool>,
) -> watch::Receiver<Arc<DnsConfig>> {
let (tx, rx) = watch::channel(Arc::new(DnsConfig::new()));
let mut catalog_rx = consul.watch_all_service_health(Duration::from_secs(60));
tokio::spawn(async move {
while !*must_exit.borrow() {
select! {
_ = catalog_rx.changed() => (),
_ = must_exit.changed() => continue,
};
let services = catalog_rx.borrow_and_update();
let mut dns_config = DnsConfig::new();
for (_svc, nodes) in services.iter() {
for node in nodes.iter() {
// Do not take into account backends if any have status critical
if node.checks.iter().any(|x| x.status == "critical") {
continue;
}
for tag in node.service.tags.iter() {
if let Some((k, v)) = parse_d53_tag(tag, &node.node) {
dns_config.add(k, v);
}
}
}
}
tx.send(Arc::new(dns_config)).expect("Internal error");
}
});
rx
}
// ---- Display impls ----
impl std::fmt::Display for DnsRecordType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
DnsRecordType::A => write!(f, "A"),
DnsRecordType::AAAA => write!(f, "AAAA"),
DnsRecordType::CNAME => write!(f, "CNAME"),
}
}
}
impl std::fmt::Display for DnsEntryKey {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{} IN {}", self.dns_path, self.record_type)
}
}
impl std::fmt::Display for DnsEntryValue {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "[")?;
for (i, tgt) in self.targets.iter().enumerate() {
if i > 0 {
write!(f, " ")?;
}
write!(f, "{}", tgt)?;
}
write!(f, "]")
}
}
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