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Refactor `control::destination::background` into smaller modules (#34) 

This branch is purely a refactor and should result in no functional 
changes.

The `control::destination::background` module has become quite large,
making the code difficult to read and review changes to. This branch
separates out the `DestinationSet` type and the destination service
client code into their own modules inside of `background`. Furthermore,
it rolls the `control::utils` module into the `client` submodule of
`background`, as that code is only used in the `client` module.

I think there's some additional work that can be done to make this code
clearer beyond simply splitting apart some of these large files, and I
intend to do some refactoring in additional follow-up branches.

Signed-off-by: Eliza Weisman <eliza@buoyant.io>
This commit is contained in:
Eliza Weisman 2018-08-01 14:14:34 -07:00 committed by GitHub
parent 51e07b2a68
commit a615834f7b
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GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 852 additions and 812 deletions
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742
src/control/destination/background.rs
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@ -1,742 +0,0 @@
use std::collections::{
hash_map::{Entry, HashMap},
VecDeque,
};
use std::fmt;
use std::iter::IntoIterator;
use std::net::SocketAddr;
use std::time::{Instant, Duration};
use bytes::Bytes;
use futures::{
future,
sync::mpsc,
Async, Future, Poll, Stream,
};
use h2;
use http;
use tower_grpc as grpc;
use tower_h2::{self, BoxBody, HttpService, RecvBody};
use tower_reconnect::Reconnect;
use linkerd2_proxy_api::destination::client::Destination;
use linkerd2_proxy_api::destination::update::Update as PbUpdate2;
use linkerd2_proxy_api::destination::{
GetDestination,
Update as PbUpdate,
WeightedAddr,
};
use linkerd2_proxy_api::net::TcpAddress;
use super::{Metadata, ResolveRequest, Responder, Update};
use config::Namespaces;
use control::{
cache::{Cache, CacheChange, Exists},
fully_qualified_authority::FullyQualifiedAuthority,
remote_stream::{Receiver, Remote},
util::{AddOrigin, Backoff, LogErrors},
};
use dns::{self, IpAddrListFuture};
use telemetry::metrics::DstLabels;
use transport::{DnsNameAndPort, HostAndPort, LookupAddressAndConnect};
use timeout::Timeout;
use transport::tls;
use conditional::Conditional;
use watch_service::{Rebind, WatchService};
use futures_watch::Watch;
type DestinationServiceQuery<T> = Remote<PbUpdate, T>;
type UpdateRx<T> = Receiver<PbUpdate, T>;
/// Type of the client service stack used to make destination requests.
type ClientService = AddOrigin<Backoff<LogErrors<Reconnect<
tower_h2::client::Connect<
Timeout<LookupAddressAndConnect>,
::logging::ContextualExecutor<
::logging::Client<
&'static str,
HostAndPort
>
>,
BoxBody,
>
>>>>;
/// Satisfies resolutions as requested via `request_rx`.
///
/// As the `Background` is polled with a client to Destination service, if the client to the
/// service is healthy, it reads requests from `request_rx`, determines how to resolve the
/// provided authority to a set of addresses, and ensures that resolution updates are
/// propagated to all requesters.
struct Background<T: HttpService<ResponseBody = RecvBody>> {
dns_resolver: dns::Resolver,
namespaces: Namespaces,
destinations: HashMap<DnsNameAndPort, DestinationSet<T>>,
/// A queue of authorities that need to be reconnected.
reconnects: VecDeque<DnsNameAndPort>,
/// The Destination.Get RPC client service.
/// Each poll, records whether the rpc service was till ready.
rpc_ready: bool,
/// A receiver of new watch requests.
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
}
/// Holds the state of a single resolution.
struct DestinationSet<T: HttpService<ResponseBody = RecvBody>> {
addrs: Exists<Cache<SocketAddr, Metadata>>,
query: Option<DestinationServiceQuery<T>>,
dns_query: Option<IpAddrListFuture>,
responders: Vec<Responder>,
}
/// The state needed to bind a new controller client stack.
struct BindClient {
backoff_delay: Duration,
identity: Conditional<tls::Identity, tls::ReasonForNoTls>,
host_and_port: HostAndPort,
dns_resolver: dns::Resolver,
log_ctx: ::logging::Client<&'static str, HostAndPort>,
}
/// Returns a new discovery background task.
pub(super) fn task(
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
dns_resolver: dns::Resolver,
namespaces: Namespaces,
host_and_port: Option<HostAndPort>,
controller_tls: tls::ConditionalConnectionConfig<tls::ClientConfigWatch>,
control_backoff_delay: Duration,
) -> impl Future<Item = (), Error = ()>
{
// Build up the Controller Client Stack
let mut client = host_and_port.map(|host_and_port| {
let (identity, watch) = match controller_tls {
Conditional::Some(cfg) =>
(Conditional::Some(cfg.server_identity), cfg.config),
Conditional::None(reason) => {
// If there's no connection config, then construct a new
// `Watch` that never updates to construct the `WatchService`.
// We do this here rather than calling `ClientConfig::no_tls`
// in order to propagate the reason for no TLS to the watch.
let (watch, _) = Watch::new(Conditional::None(reason));
(Conditional::None(reason), watch)
},
};
let bind_client = BindClient::new(
identity,
&dns_resolver,
host_and_port,
control_backoff_delay,
);
WatchService::new(watch, bind_client)
});
let mut disco = Background::new(
request_rx,
dns_resolver,
namespaces,
);
future::poll_fn(move || {
disco.poll_rpc(&mut client)
})
}
// ==== impl Background =====
impl<T> Background<T>
where
T: HttpService<RequestBody = BoxBody, ResponseBody = RecvBody>,
T::Error: fmt::Debug,
{
fn new(
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
dns_resolver: dns::Resolver,
namespaces: Namespaces,
) -> Self {
Self {
dns_resolver,
namespaces,
destinations: HashMap::new(),
reconnects: VecDeque::new(),
rpc_ready: false,
request_rx,
}
}
fn poll_rpc(&mut self, client: &mut Option<T>) -> Poll<(), ()> {
// This loop is make sure any streams that were found disconnected
// in `poll_destinations` while the `rpc` service is ready should
// be reconnected now, otherwise the task would just sleep...
loop {
if let Async::Ready(()) = self.poll_resolve_requests(client) {
// request_rx has closed, meaning the main thread is terminating.
return Ok(Async::Ready(()));
}
self.retain_active_destinations();
self.poll_destinations();
if self.reconnects.is_empty() || !self.rpc_ready {
return Ok(Async::NotReady);
}
}
}
fn poll_resolve_requests(&mut self, client: &mut Option<T>) -> Async<()> {
loop {
if let Some(client) = client {
// if rpc service isn't ready, not much we can do...
match client.poll_ready() {
Ok(Async::Ready(())) => {
self.rpc_ready = true;
},
Ok(Async::NotReady) => {
self.rpc_ready = false;
return Async::NotReady;
},
Err(err) => {
warn!("Destination.Get poll_ready error: {:?}", err);
self.rpc_ready = false;
return Async::NotReady;
},
}
// handle any pending reconnects first
if self.poll_reconnect(client) {
continue;
}
}
// check for any new watches
match self.request_rx.poll() {
Ok(Async::Ready(Some(resolve))) => {
trace!("Destination.Get {:?}", resolve.authority);
match self.destinations.entry(resolve.authority) {
Entry::Occupied(mut occ) => {
let set = occ.get_mut();
// we may already know of some addresses here, so push
// them onto the new watch first
match set.addrs {
Exists::Yes(ref cache) => for (&addr, meta) in cache {
let update = Update::Bind(addr, meta.clone());
resolve.responder.update_tx
.unbounded_send(update)
.expect("unbounded_send does not fail");
},
Exists::No | Exists::Unknown => (),
}
set.responders.push(resolve.responder);
},
Entry::Vacant(vac) => {
let pod_namespace = &self.namespaces.pod;
let query = client.as_mut().and_then(|client| {
Self::query_destination_service_if_relevant(
pod_namespace,
client,
vac.key(),
"connect",
)
});
let mut set = DestinationSet {
addrs: Exists::Unknown,
query,
dns_query: None,
responders: vec![resolve.responder],
};
// If the authority is one for which the Destination service is never
// relevant (e.g. an absolute name that doesn't end in ".svc.$zone." in
// Kubernetes), or if we don't have a `client`, then immediately start
// polling DNS.
if set.query.is_none() {
set.reset_dns_query(
&self.dns_resolver,
Instant::now(),
vac.key(),
);
}
vac.insert(set);
},
}
},
Ok(Async::Ready(None)) => {
trace!("Discover tx is dropped, shutdown");
return Async::Ready(());
},
Ok(Async::NotReady) => return Async::NotReady,
Err(_) => unreachable!("unbounded receiver doesn't error"),
}
}
}
/// Tries to reconnect next watch stream. Returns true if reconnection started.
fn poll_reconnect(&mut self, client: &mut T) -> bool {
debug_assert!(self.rpc_ready);
while let Some(auth) = self.reconnects.pop_front() {
if let Some(set) = self.destinations.get_mut(&auth) {
set.query = Self::query_destination_service_if_relevant(
&self.namespaces.pod,
client,
&auth,
"reconnect",
);
return true;
} else {
trace!("reconnect no longer needed: {:?}", auth);
}
}
false
}
/// Ensures that `destinations` is updated to only maintain active resolutions.
///
/// If there are no active resolutions for a destination, the destination is removed.
fn retain_active_destinations(&mut self) {
self.destinations.retain(|_, ref mut dst| {
dst.responders.retain(|r| r.is_active());
dst.responders.len() > 0
})
}
fn poll_destinations(&mut self) {
for (auth, set) in &mut self.destinations {
// Query the Destination service first.
let (new_query, found_by_destination_service) = match set.query.take() {
Some(Remote::ConnectedOrConnecting { rx }) => {
let (new_query, found_by_destination_service) =
set.poll_destination_service(
auth, rx, self.namespaces.tls_controller.as_ref().map(|s| s.as_ref()));
if let Remote::NeedsReconnect = new_query {
set.reset_on_next_modification();
self.reconnects.push_back(auth.clone());
}
(Some(new_query), found_by_destination_service)
},
query => (query, Exists::Unknown),
};
set.query = new_query;
// Any active response from the Destination service cancels the DNS query except for a
// positive assertion that the service doesn't exist.
//
// Any disconnection from the Destination service has no effect on the DNS query; we
// assume that if we were querying DNS before, we should continue to do so, and if we
// weren't querying DNS then we shouldn't start now. In particular, temporary
// disruptions of connectivity to the Destination service do not cause a fallback to
// DNS.
match found_by_destination_service {
Exists::Yes(()) => {
// Stop polling DNS on any active update from the Destination service.
set.dns_query = None;
},
Exists::No => {
// Fall back to DNS.
set.reset_dns_query(&self.dns_resolver, Instant::now(), auth);
},
Exists::Unknown => (), // No change from Destination service's perspective.
}
// Poll DNS after polling the Destination service. This may reset the DNS query but it
// won't affect the Destination Service query.
set.poll_dns(&self.dns_resolver, auth);
}
}
/// Initiates a query `query` to the Destination service and returns it as
/// `Some(query)` if the given authority's host is of a form suitable for using to
/// query the Destination service. Otherwise, returns `None`.
fn query_destination_service_if_relevant(
default_destination_namespace: &str,
client: &mut T,
auth: &DnsNameAndPort,
connect_or_reconnect: &str,
) -> Option<DestinationServiceQuery<T>> {
trace!(
"DestinationServiceQuery {} {:?}",
connect_or_reconnect,
auth
);
FullyQualifiedAuthority::normalize(auth, default_destination_namespace).map(|auth| {
let req = GetDestination {
scheme: "k8s".into(),
path: auth.without_trailing_dot().to_owned(),
};
let mut svc = Destination::new(client.lift_ref());
let response = svc.get(grpc::Request::new(req));
Remote::ConnectedOrConnecting {
rx: Receiver::new(response),
}
})
}
}
// ===== impl DestinationSet =====
impl<T> DestinationSet<T>
where
T: HttpService<RequestBody = BoxBody, ResponseBody = RecvBody>,
T::Error: fmt::Debug,
{
fn reset_dns_query(
&mut self,
dns_resolver: &dns::Resolver,
deadline: Instant,
authority: &DnsNameAndPort,
) {
trace!(
"resetting DNS query for {} at {:?}",
authority.host,
deadline
);
self.reset_on_next_modification();
self.dns_query = Some(dns_resolver.resolve_all_ips(deadline, &authority.host));
}
// Processes Destination service updates from `request_rx`, returning the new query
// and an indication of any *change* to whether the service exists as far as the
// Destination service is concerned, where `Exists::Unknown` is to be interpreted as
// "no change in existence" instead of "unknown".
fn poll_destination_service(
&mut self,
auth: &DnsNameAndPort,
mut rx: UpdateRx<T>,
tls_controller_namespace: Option<&str>,
) -> (DestinationServiceQuery<T>, Exists<()>) {
let mut exists = Exists::Unknown;
loop {
match rx.poll() {
Ok(Async::Ready(Some(update))) => match update.update {
Some(PbUpdate2::Add(a_set)) => {
let set_labels = a_set.metric_labels;
let addrs = a_set
.addrs
.into_iter()
.filter_map(|pb|
pb_to_addr_meta(pb, &set_labels, tls_controller_namespace));
self.add(auth, addrs)
},
Some(PbUpdate2::Remove(r_set)) => {
exists = Exists::Yes(());
self.remove(
auth,
r_set
.addrs
.iter()
.filter_map(|addr| pb_to_sock_addr(addr.clone())),
);
},
Some(PbUpdate2::NoEndpoints(ref no_endpoints)) if no_endpoints.exists => {
exists = Exists::Yes(());
self.no_endpoints(auth, no_endpoints.exists);
},
Some(PbUpdate2::NoEndpoints(no_endpoints)) => {
debug_assert!(!no_endpoints.exists);
exists = Exists::No;
},
None => (),
},
Ok(Async::Ready(None)) => {
trace!(
"Destination.Get stream ended for {:?}, must reconnect",
auth
);
return (Remote::NeedsReconnect, exists);
},
Ok(Async::NotReady) => {
return (Remote::ConnectedOrConnecting { rx }, exists);
},
Err(err) => {
warn!("Destination.Get stream errored for {:?}: {:?}", auth, err);
return (Remote::NeedsReconnect, exists);
},
};
}
}
fn poll_dns(&mut self, dns_resolver: &dns::Resolver, authority: &DnsNameAndPort) {
// Duration to wait before polling DNS again after an error
// (or a NXDOMAIN response with no TTL).
const DNS_ERROR_TTL: Duration = Duration::from_secs(5);
trace!("checking DNS for {:?}", authority);
while let Some(mut query) = self.dns_query.take() {
trace!("polling DNS for {:?}", authority);
let deadline = match query.poll() {
Ok(Async::NotReady) => {
trace!("DNS query not ready {:?}", authority);
self.dns_query = Some(query);
return;
},
Ok(Async::Ready(dns::Response::Exists(ips))) => {
trace!(
"positive result of DNS query for {:?}: {:?}",
authority,
ips
);
self.add(
authority,
ips.iter().map(|ip| {
(
SocketAddr::from((ip, authority.port)),
Metadata::no_metadata(),
)
}),
);
// Poll again after the deadline on the DNS response.
ips.valid_until()
},
Ok(Async::Ready(dns::Response::DoesNotExist { retry_after })) => {
trace!(
"negative result (NXDOMAIN) of DNS query for {:?}",
authority
);
self.no_endpoints(authority, false);
// Poll again after the deadline on the DNS response, if
// there is one.
retry_after.unwrap_or_else(|| Instant::now() + DNS_ERROR_TTL)
},
Err(e) => {
// Do nothing so that the most recent non-error response is used until a
// non-error response is received
trace!("DNS resolution failed for {}: {}", &authority.host, e);
// Poll again after the default wait time.
Instant::now() + DNS_ERROR_TTL
},
};
self.reset_dns_query(dns_resolver, deadline, &authority)
}
}
}
impl<T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
fn reset_on_next_modification(&mut self) {
match self.addrs {
Exists::Yes(ref mut cache) => {
cache.set_reset_on_next_modification();
},
Exists::No | Exists::Unknown => (),
}
}
fn add<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_add: A)
where
A: Iterator<Item = (SocketAddr, Metadata)>,
{
let mut cache = match self.addrs.take() {
Exists::Yes(mut cache) => cache,
Exists::Unknown | Exists::No => Cache::new(),
};
cache.update_union(addrs_to_add, &mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
self.addrs = Exists::Yes(cache);
}
fn remove<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_remove: A)
where
A: Iterator<Item = SocketAddr>,
{
let cache = match self.addrs.take() {
Exists::Yes(mut cache) => {
cache.remove(addrs_to_remove, &mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
cache
},
Exists::Unknown | Exists::No => Cache::new(),
};
self.addrs = Exists::Yes(cache);
}
fn no_endpoints(&mut self, authority_for_logging: &DnsNameAndPort, exists: bool) {
trace!(
"no endpoints for {:?} that is known to {}",
authority_for_logging,
if exists { "exist" } else { "not exist" }
);
match self.addrs.take() {
Exists::Yes(mut cache) => {
cache.clear(&mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
},
Exists::Unknown | Exists::No => (),
};
self.addrs = if exists {
Exists::Yes(Cache::new())
} else {
Exists::No
};
}
fn on_change(
responders: &mut Vec<Responder>,
authority_for_logging: &DnsNameAndPort,
change: CacheChange<SocketAddr, Metadata>,
) {
let (update_str, update, addr) = match change {
CacheChange::Insertion { key, value } => {
("insert", Update::Bind(key, value.clone()), key)
},
CacheChange::Removal { key } => ("remove", Update::Remove(key), key),
CacheChange::Modification { key, new_value } => (
"change metadata for",
Update::Bind(key, new_value.clone()),
key,
),
};
trace!("{} {:?} for {:?}", update_str, addr, authority_for_logging);
// retain is used to drop any senders that are dead
responders.retain(|r| {
let sent = r.update_tx.unbounded_send(update.clone());
sent.is_ok()
});
}
}
// ===== impl BindClient =====
impl BindClient {
fn new(
identity: Conditional<tls::Identity, tls::ReasonForNoTls>,
dns_resolver: &dns::Resolver,
host_and_port: HostAndPort,
backoff_delay: Duration,
) -> Self {
let log_ctx = ::logging::admin().client("control", host_and_port.clone());
Self {
backoff_delay,
identity,
dns_resolver: dns_resolver.clone(),
host_and_port,
log_ctx,
}
}
}
impl Rebind<tls::ConditionalClientConfig> for BindClient {
type Service = ClientService;
fn rebind(
&mut self,
client_cfg: &tls::ConditionalClientConfig,
) -> Self::Service {
let conn_cfg = match (&self.identity, client_cfg) {
(Conditional::Some(ref id), Conditional::Some(ref cfg)) =>
Conditional::Some(tls::ConnectionConfig {
server_identity: id.clone(),
config: cfg.clone(),
}),
(Conditional::None(ref reason), _) |
(_, Conditional::None(ref reason)) =>
Conditional::None(reason.clone()),
};
let scheme = http::uri::Scheme::from_shared(Bytes::from_static(b"http")).unwrap();
let authority = http::uri::Authority::from(&self.host_and_port);
let connect = Timeout::new(
LookupAddressAndConnect::new(self.host_and_port.clone(),
self.dns_resolver.clone(),
conn_cfg),
Duration::from_secs(3),
);
let h2_client = tower_h2::client::Connect::new(
connect,
h2::client::Builder::default(),
self.log_ctx.clone().executor()
);
let reconnect = Reconnect::new(h2_client);
let log_errors = LogErrors::new(reconnect);
let backoff = Backoff::new(log_errors, self.backoff_delay);
// TODO: Use AddOrigin in tower-http
AddOrigin::new(scheme, authority, backoff)
}
}
/// Construct a new labeled `SocketAddr `from a protobuf `WeightedAddr`.
fn pb_to_addr_meta(
pb: WeightedAddr,
set_labels: &HashMap<String, String>,
tls_controller_namespace: Option<&str>,
) -> Option<(SocketAddr, Metadata)> {
let addr = pb.addr.and_then(pb_to_sock_addr)?;
let mut labels = set_labels.iter()
.chain(pb.metric_labels.iter())
.collect::<Vec<_>>();
labels.sort_by(|(k0, _), (k1, _)| k0.cmp(k1));
let mut tls_identity =
Conditional::None(tls::ReasonForNoIdentity::NotProvidedByServiceDiscovery);
if let Some(pb) = pb.tls_identity {
match tls::Identity::maybe_from_protobuf(tls_controller_namespace, pb) {
Ok(Some(identity)) => {
tls_identity = Conditional::Some(identity);
},
Ok(None) => (),
Err(e) => {
error!("Failed to parse TLS identity: {:?}", e);
// XXX: Wallpaper over the error and keep going without TLS.
// TODO: Hard fail here once the TLS infrastructure has been
// validated.
},
}
};
let meta = Metadata::new(DstLabels::new(labels.into_iter()), tls_identity);
Some((addr, meta))
}
fn pb_to_sock_addr(pb: TcpAddress) -> Option<SocketAddr> {
use linkerd2_proxy_api::net::ip_address::Ip;
use std::net::{Ipv4Addr, Ipv6Addr};
/*
current structure is:
TcpAddress {
ip: Option<IpAddress {
ip: Option<enum Ip {
Ipv4(u32),
Ipv6(IPv6 {
first: u64,
last: u64,
}),
}>,
}>,
port: u32,
}
*/
match pb.ip {
Some(ip) => match ip.ip {
Some(Ip::Ipv4(octets)) => {
let ipv4 = Ipv4Addr::from(octets);
Some(SocketAddr::from((ipv4, pb.port as u16)))
},
Some(Ip::Ipv6(v6)) => {
let octets = [
(v6.first >> 56) as u8,
(v6.first >> 48) as u8,
(v6.first >> 40) as u8,
(v6.first >> 32) as u8,
(v6.first >> 24) as u8,
(v6.first >> 16) as u8,
(v6.first >> 8) as u8,
v6.first as u8,
(v6.last >> 56) as u8,
(v6.last >> 48) as u8,
(v6.last >> 40) as u8,
(v6.last >> 32) as u8,
(v6.last >> 24) as u8,
(v6.last >> 16) as u8,
(v6.last >> 8) as u8,
v6.last as u8,
];
let ipv6 = Ipv6Addr::from(octets);
Some(SocketAddr::from((ipv6, pb.port as u16)))
},
None => None,
},
None => None,
}
}

233
src/control/util.rs → src/control/destination/background/client.rs
View File

@ -1,16 +1,46 @@
use std::{
fmt,
io,
time::{Duration, Instant},
};
use bytes::Bytes;
use futures::{Async, Future, Poll}; use futures::{Async, Future, Poll};
use h2;
use http; use http;
use std::fmt;
use std::io;
use std::time::{Duration, Instant};
use tokio::timer::Delay; use tokio::timer::Delay;
use tower_h2::{self, BoxBody};
use tower_service::Service; use tower_service::Service;
use tower_h2; use tower_reconnect::{Reconnect, Error as ReconnectError};
use tower_reconnect::{Error as ReconnectError}; use conditional::Conditional;
use dns;
use timeout::{Timeout, TimeoutError};
use transport::{tls, HostAndPort, LookupAddressAndConnect};
use watch_service::Rebind;
use timeout::TimeoutError; /// Type of the client service stack used to make destination requests.
pub(super) type ClientService = AddOrigin<Backoff<LogErrors<Reconnect<
tower_h2::client::Connect<
Timeout<LookupAddressAndConnect>,
::logging::ContextualExecutor<
::logging::Client<
&'static str,
HostAndPort
>
>,
BoxBody,
>
>>>>;
// ===== Backoff ===== /// The state needed to bind a new controller client stack.
pub(super) struct BindClient {
backoff_delay: Duration,
identity: Conditional<tls::Identity, tls::ReasonForNoTls>,
host_and_port: HostAndPort,
dns_resolver: dns::Resolver,
log_ctx: ::logging::Client<&'static str, HostAndPort>,
}
/// Wait a duration if inner `poll_ready` returns an error. /// Wait a duration if inner `poll_ready` returns an error.
//TODO: move to tower-backoff //TODO: move to tower-backoff
@ -21,6 +51,96 @@ pub(super) struct Backoff<S> {
wait_dur: Duration, wait_dur: Duration,
} }
/// Wraps an HTTP service, injecting authority and scheme on every request.
pub(super) struct AddOrigin<S> {
authority: http::uri::Authority,
inner: S,
scheme: http::uri::Scheme,
}
/// Log errors talking to the controller in human format.
pub(super) struct LogErrors<S> {
inner: S,
}
// We want some friendly logs, but the stack of services don't have fmt::Display
// errors, so we have to build that ourselves. For now, this hard codes the
// expected error stack, and so any new middleware added will need to adjust this.
//
// The dead_code allowance is because rustc is being stupid and doesn't see it
// is used down below.
#[allow(dead_code)]
type LogError = ReconnectError<
tower_h2::client::Error,
tower_h2::client::ConnectError<
TimeoutError<
io::Error
>
>
>;
// ===== impl BindClient =====
impl BindClient {
pub(super) fn new(
identity: Conditional<tls::Identity, tls::ReasonForNoTls>,
dns_resolver: &dns::Resolver,
host_and_port: HostAndPort,
backoff_delay: Duration,
) -> Self {
let log_ctx = ::logging::admin().client("control", host_and_port.clone());
Self {
backoff_delay,
identity,
dns_resolver: dns_resolver.clone(),
host_and_port,
log_ctx,
}
}
}
impl Rebind<tls::ConditionalClientConfig> for BindClient {
type Service = ClientService;
fn rebind(
&mut self,
client_cfg: &tls::ConditionalClientConfig,
) -> Self::Service {
let conn_cfg = match (&self.identity, client_cfg) {
(Conditional::Some(ref id), Conditional::Some(ref cfg)) =>
Conditional::Some(tls::ConnectionConfig {
server_identity: id.clone(),
config: cfg.clone(),
}),
(Conditional::None(ref reason), _) |
(_, Conditional::None(ref reason)) =>
Conditional::None(reason.clone()),
};
let scheme = http::uri::Scheme::from_shared(Bytes::from_static(b"http")).unwrap();
let authority = http::uri::Authority::from(&self.host_and_port);
let connect = Timeout::new(
LookupAddressAndConnect::new(self.host_and_port.clone(),
self.dns_resolver.clone(),
conn_cfg),
Duration::from_secs(3),
);
let h2_client = tower_h2::client::Connect::new(
connect,
h2::client::Builder::default(),
self.log_ctx.clone().executor()
);
let reconnect = Reconnect::new(h2_client);
let log_errors = LogErrors::new(reconnect);
let backoff = Backoff::new(log_errors, self.backoff_delay);
// TODO: Use AddOrigin in tower-http
AddOrigin::new(scheme, authority, backoff)
}
}
// ===== impl Backoff =====
impl<S> Backoff<S> impl<S> Backoff<S>
where where
S: Service, S: Service,
@ -80,69 +200,8 @@ where
} }
} }
/// Wraps an HTTP service, injecting authority and scheme on every request.
pub(super) struct AddOrigin<S> {
authority: http::uri::Authority,
inner: S,
scheme: http::uri::Scheme,
}
impl<S> AddOrigin<S> { // ===== impl LogErrors =====
pub(super) fn new(scheme: http::uri::Scheme, auth: http::uri::Authority, service: S) -> Self {
AddOrigin {
authority: auth,
inner: service,
scheme,
}
}
}
impl<S, B> Service for AddOrigin<S>
where
S: Service<Request = http::Request<B>>,
{
type Request = http::Request<B>;
type Response = S::Response;
type Error = S::Error;
type Future = S::Future;
fn poll_ready(&mut self) -> Poll<(), Self::Error> {
self.inner.poll_ready()
}
fn call(&mut self, req: Self::Request) -> Self::Future {
let (mut head, body) = req.into_parts();
let mut uri: http::uri::Parts = head.uri.into();
uri.scheme = Some(self.scheme.clone());
uri.authority = Some(self.authority.clone());
head.uri = http::Uri::from_parts(uri).expect("valid uri");
self.inner.call(http::Request::from_parts(head, body))
}
}
// ===== impl LogErrors
/// Log errors talking to the controller in human format.
pub(super) struct LogErrors<S> {
inner: S,
}
// We want some friendly logs, but the stack of services don't have fmt::Display
// errors, so we have to build that ourselves. For now, this hard codes the
// expected error stack, and so any new middleware added will need to adjust this.
//
// The dead_code allowance is because rustc is being stupid and doesn't see it
// is used down below.
#[allow(dead_code)]
type LogError = ReconnectError<
tower_h2::client::Error,
tower_h2::client::ConnectError<
TimeoutError<
io::Error
>
>
>;
impl<S> LogErrors<S> impl<S> LogErrors<S>
where where
@ -197,6 +256,42 @@ impl<'a> fmt::Display for HumanError<'a> {
} }
} }
// ===== impl AddOrigin =====
impl<S> AddOrigin<S> {
pub(super) fn new(scheme: http::uri::Scheme, auth: http::uri::Authority, service: S) -> Self {
AddOrigin {
authority: auth,
inner: service,
scheme,
}
}
}
impl<S, B> Service for AddOrigin<S>
where
S: Service<Request = http::Request<B>>,
{
type Request = http::Request<B>;
type Response = S::Response;
type Error = S::Error;
type Future = S::Future;
fn poll_ready(&mut self) -> Poll<(), Self::Error> {
self.inner.poll_ready()
}
fn call(&mut self, req: Self::Request) -> Self::Future {
let (mut head, body) = req.into_parts();
let mut uri: http::uri::Parts = head.uri.into();
uri.scheme = Some(self.scheme.clone());
uri.authority = Some(self.authority.clone());
head.uri = http::Uri::from_parts(uri).expect("valid uri");
self.inner.call(http::Request::from_parts(head, body))
}
}
#[cfg(test)] #[cfg(test)]
mod tests { mod tests {
use super::*; use super::*;

352
src/control/destination/background/destination_set.rs Normal file
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@ -0,0 +1,352 @@
use std::{
collections::HashMap,
fmt,
iter::IntoIterator,
net::SocketAddr,
time::{Instant, Duration},
};
use futures::{Async, Future, Stream,};
use tower_h2::{BoxBody, HttpService, RecvBody};
use linkerd2_proxy_api::{
destination::{
update::Update as PbUpdate2,
WeightedAddr,
},
net::TcpAddress,
};
use super::super::{Metadata, Responder, Update};
use control::{
cache::{Cache, CacheChange, Exists},
remote_stream::Remote,
};
use dns::{self, IpAddrListFuture};
use telemetry::metrics::DstLabels;
use transport::{tls, DnsNameAndPort};
use conditional::Conditional;
use super::{DestinationServiceQuery, UpdateRx};
/// Holds the state of a single resolution.
pub(super) struct DestinationSet<T: HttpService<ResponseBody = RecvBody>> {
pub addrs: Exists<Cache<SocketAddr, Metadata>>,
pub query: Option<DestinationServiceQuery<T>>,
pub dns_query: Option<IpAddrListFuture>,
pub responders: Vec<Responder>,
}
// ===== impl DestinationSet =====
impl<T> DestinationSet<T>
where
T: HttpService<RequestBody = BoxBody, ResponseBody = RecvBody>,
T::Error: fmt::Debug,
{
pub(super) fn reset_dns_query(
&mut self,
dns_resolver: &dns::Resolver,
deadline: Instant,
authority: &DnsNameAndPort,
) {
trace!(
"resetting DNS query for {} at {:?}",
authority.host,
deadline
);
self.reset_on_next_modification();
self.dns_query = Some(dns_resolver.resolve_all_ips(deadline, &authority.host));
}
// Processes Destination service updates from `request_rx`, returning the new query
// and an indication of any *change* to whether the service exists as far as the
// Destination service is concerned, where `Exists::Unknown` is to be interpreted as
// "no change in existence" instead of "unknown".
pub(super) fn poll_destination_service(
&mut self,
auth: &DnsNameAndPort,
mut rx: UpdateRx<T>,
tls_controller_namespace: Option<&str>,
) -> (DestinationServiceQuery<T>, Exists<()>) {
let mut exists = Exists::Unknown;
loop {
match rx.poll() {
Ok(Async::Ready(Some(update))) => match update.update {
Some(PbUpdate2::Add(a_set)) => {
let set_labels = a_set.metric_labels;
let addrs = a_set
.addrs
.into_iter()
.filter_map(|pb|
pb_to_addr_meta(pb, &set_labels, tls_controller_namespace));
self.add(auth, addrs)
},
Some(PbUpdate2::Remove(r_set)) => {
exists = Exists::Yes(());
self.remove(
auth,
r_set
.addrs
.iter()
.filter_map(|addr| pb_to_sock_addr(addr.clone())),
);
},
Some(PbUpdate2::NoEndpoints(ref no_endpoints)) if no_endpoints.exists => {
exists = Exists::Yes(());
self.no_endpoints(auth, no_endpoints.exists);
},
Some(PbUpdate2::NoEndpoints(no_endpoints)) => {
debug_assert!(!no_endpoints.exists);
exists = Exists::No;
},
None => (),
},
Ok(Async::Ready(None)) => {
trace!(
"Destination.Get stream ended for {:?}, must reconnect",
auth
);
return (Remote::NeedsReconnect, exists);
},
Ok(Async::NotReady) => {
return (Remote::ConnectedOrConnecting { rx }, exists);
},
Err(err) => {
warn!("Destination.Get stream errored for {:?}: {:?}", auth, err);
return (Remote::NeedsReconnect, exists);
},
};
}
}
pub(super) fn poll_dns(&mut self, dns_resolver: &dns::Resolver, authority: &DnsNameAndPort) {
// Duration to wait before polling DNS again after an error
// (or a NXDOMAIN response with no TTL).
const DNS_ERROR_TTL: Duration = Duration::from_secs(5);
trace!("checking DNS for {:?}", authority);
while let Some(mut query) = self.dns_query.take() {
trace!("polling DNS for {:?}", authority);
let deadline = match query.poll() {
Ok(Async::NotReady) => {
trace!("DNS query not ready {:?}", authority);
self.dns_query = Some(query);
return;
},
Ok(Async::Ready(dns::Response::Exists(ips))) => {
trace!(
"positive result of DNS query for {:?}: {:?}",
authority,
ips
);
self.add(
authority,
ips.iter().map(|ip| {
(
SocketAddr::from((ip, authority.port)),
Metadata::no_metadata(),
)
}),
);
// Poll again after the deadline on the DNS response.
ips.valid_until()
},
Ok(Async::Ready(dns::Response::DoesNotExist { retry_after })) => {
trace!(
"negative result (NXDOMAIN) of DNS query for {:?}",
authority
);
self.no_endpoints(authority, false);
// Poll again after the deadline on the DNS response, if
// there is one.
retry_after.unwrap_or_else(|| Instant::now() + DNS_ERROR_TTL)
},
Err(e) => {
// Do nothing so that the most recent non-error response is used until a
// non-error response is received
trace!("DNS resolution failed for {}: {}", &authority.host, e);
// Poll again after the default wait time.
Instant::now() + DNS_ERROR_TTL
},
};
self.reset_dns_query(dns_resolver, deadline, &authority)
}
}
}
impl<T: HttpService<ResponseBody = RecvBody>> DestinationSet<T> {
pub(super) fn reset_on_next_modification(&mut self) {
match self.addrs {
Exists::Yes(ref mut cache) => {
cache.set_reset_on_next_modification();
},
Exists::No | Exists::Unknown => (),
}
}
fn add<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_add: A)
where
A: Iterator<Item = (SocketAddr, Metadata)>,
{
let mut cache = match self.addrs.take() {
Exists::Yes(mut cache) => cache,
Exists::Unknown | Exists::No => Cache::new(),
};
cache.update_union(addrs_to_add, &mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
self.addrs = Exists::Yes(cache);
}
fn remove<A>(&mut self, authority_for_logging: &DnsNameAndPort, addrs_to_remove: A)
where
A: Iterator<Item = SocketAddr>,
{
let cache = match self.addrs.take() {
Exists::Yes(mut cache) => {
cache.remove(addrs_to_remove, &mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
cache
},
Exists::Unknown | Exists::No => Cache::new(),
};
self.addrs = Exists::Yes(cache);
}
fn no_endpoints(&mut self, authority_for_logging: &DnsNameAndPort, exists: bool) {
trace!(
"no endpoints for {:?} that is known to {}",
authority_for_logging,
if exists { "exist" } else { "not exist" }
);
match self.addrs.take() {
Exists::Yes(mut cache) => {
cache.clear(&mut |change| {
Self::on_change(&mut self.responders, authority_for_logging, change)
});
},
Exists::Unknown | Exists::No => (),
};
self.addrs = if exists {
Exists::Yes(Cache::new())
} else {
Exists::No
};
}
fn on_change(
responders: &mut Vec<Responder>,
authority_for_logging: &DnsNameAndPort,
change: CacheChange<SocketAddr, Metadata>,
) {
let (update_str, update, addr) = match change {
CacheChange::Insertion { key, value } => {
("insert", Update::Bind(key, value.clone()), key)
},
CacheChange::Removal { key } => ("remove", Update::Remove(key), key),
CacheChange::Modification { key, new_value } => (
"change metadata for",
Update::Bind(key, new_value.clone()),
key,
),
};
trace!("{} {:?} for {:?}", update_str, addr, authority_for_logging);
// retain is used to drop any senders that are dead
responders.retain(|r| {
let sent = r.update_tx.unbounded_send(update.clone());
sent.is_ok()
});
}
}
/// Construct a new labeled `SocketAddr `from a protobuf `WeightedAddr`.
fn pb_to_addr_meta(
pb: WeightedAddr,
set_labels: &HashMap<String, String>,
tls_controller_namespace: Option<&str>,
) -> Option<(SocketAddr, Metadata)> {
let addr = pb.addr.and_then(pb_to_sock_addr)?;
let mut labels = set_labels.iter()
.chain(pb.metric_labels.iter())
.collect::<Vec<_>>();
labels.sort_by(|(k0, _), (k1, _)| k0.cmp(k1));
let mut tls_identity =
Conditional::None(tls::ReasonForNoIdentity::NotProvidedByServiceDiscovery);
if let Some(pb) = pb.tls_identity {
match tls::Identity::maybe_from_protobuf(tls_controller_namespace, pb) {
Ok(Some(identity)) => {
tls_identity = Conditional::Some(identity);
},
Ok(None) => (),
Err(e) => {
error!("Failed to parse TLS identity: {:?}", e);
// XXX: Wallpaper over the error and keep going without TLS.
// TODO: Hard fail here once the TLS infrastructure has been
// validated.
},
}
};
let meta = Metadata::new(DstLabels::new(labels.into_iter()), tls_identity);
Some((addr, meta))
}
fn pb_to_sock_addr(pb: TcpAddress) -> Option<SocketAddr> {
use linkerd2_proxy_api::net::ip_address::Ip;
use std::net::{Ipv4Addr, Ipv6Addr};
/*
current structure is:
TcpAddress {
ip: Option<IpAddress {
ip: Option<enum Ip {
Ipv4(u32),
Ipv6(IPv6 {
first: u64,
last: u64,
}),
}>,
}>,
port: u32,
}
*/
match pb.ip {
Some(ip) => match ip.ip {
Some(Ip::Ipv4(octets)) => {
let ipv4 = Ipv4Addr::from(octets);
Some(SocketAddr::from((ipv4, pb.port as u16)))
},
Some(Ip::Ipv6(v6)) => {
let octets = [
(v6.first >> 56) as u8,
(v6.first >> 48) as u8,
(v6.first >> 40) as u8,
(v6.first >> 32) as u8,
(v6.first >> 24) as u8,
(v6.first >> 16) as u8,
(v6.first >> 8) as u8,
v6.first as u8,
(v6.last >> 56) as u8,
(v6.last >> 48) as u8,
(v6.last >> 40) as u8,
(v6.last >> 32) as u8,
(v6.last >> 24) as u8,
(v6.last >> 16) as u8,
(v6.last >> 8) as u8,
v6.last as u8,
];
let ipv6 = Ipv6Addr::from(octets);
Some(SocketAddr::from((ipv6, pb.port as u16)))
},
None => None,
},
None => None,
}
}

336
src/control/destination/background/mod.rs Normal file
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@ -0,0 +1,336 @@
use std::{
collections::{
hash_map::{Entry, HashMap},
VecDeque,
},
fmt,
time::{Instant, Duration},
};
use futures::{
future,
sync::mpsc,
Async, Future, Poll, Stream,
};
use tower_grpc as grpc;
use tower_h2::{BoxBody, HttpService, RecvBody};
use linkerd2_proxy_api::destination::client::Destination;
use linkerd2_proxy_api::destination::{
GetDestination,
Update as PbUpdate,
};
use super::{ResolveRequest, Update};
use config::Namespaces;
use control::{
cache::Exists,
fully_qualified_authority::FullyQualifiedAuthority,
remote_stream::{Receiver, Remote},
};
use dns;
use transport::{tls, DnsNameAndPort, HostAndPort};
use conditional::Conditional;
use watch_service::WatchService;
use futures_watch::Watch;
mod client;
mod destination_set;
use self::{
client::BindClient,
destination_set::DestinationSet,
};
type DestinationServiceQuery<T> = Remote<PbUpdate, T>;
type UpdateRx<T> = Receiver<PbUpdate, T>;
/// Satisfies resolutions as requested via `request_rx`.
///
/// As the `Background` is polled with a client to Destination service, if the client to the
/// service is healthy, it reads requests from `request_rx`, determines how to resolve the
/// provided authority to a set of addresses, and ensures that resolution updates are
/// propagated to all requesters.
struct Background<T: HttpService<ResponseBody = RecvBody>> {
dns_resolver: dns::Resolver,
namespaces: Namespaces,
destinations: HashMap<DnsNameAndPort, DestinationSet<T>>,
/// A queue of authorities that need to be reconnected.
reconnects: VecDeque<DnsNameAndPort>,
/// The Destination.Get RPC client service.
/// Each poll, records whether the rpc service was till ready.
rpc_ready: bool,
/// A receiver of new watch requests.
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
}
/// Returns a new discovery background task.
pub(super) fn task(
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
dns_resolver: dns::Resolver,
namespaces: Namespaces,
host_and_port: Option<HostAndPort>,
controller_tls: tls::ConditionalConnectionConfig<tls::ClientConfigWatch>,
control_backoff_delay: Duration,
) -> impl Future<Item = (), Error = ()>
{
// Build up the Controller Client Stack
let mut client = host_and_port.map(|host_and_port| {
let (identity, watch) = match controller_tls {
Conditional::Some(cfg) =>
(Conditional::Some(cfg.server_identity), cfg.config),
Conditional::None(reason) => {
// If there's no connection config, then construct a new
// `Watch` that never updates to construct the `WatchService`.
// We do this here rather than calling `ClientConfig::no_tls`
// in order to propagate the reason for no TLS to the watch.
let (watch, _) = Watch::new(Conditional::None(reason));
(Conditional::None(reason), watch)
},
};
let bind_client = BindClient::new(
identity,
&dns_resolver,
host_and_port,
control_backoff_delay,
);
WatchService::new(watch, bind_client)
});
let mut disco = Background::new(
request_rx,
dns_resolver,
namespaces,
);
future::poll_fn(move || {
disco.poll_rpc(&mut client)
})
}
// ==== impl Background =====
impl<T> Background<T>
where
T: HttpService<RequestBody = BoxBody, ResponseBody = RecvBody>,
T::Error: fmt::Debug,
{
fn new(
request_rx: mpsc::UnboundedReceiver<ResolveRequest>,
dns_resolver: dns::Resolver,
namespaces: Namespaces,
) -> Self {
Self {
dns_resolver,
namespaces,
destinations: HashMap::new(),
reconnects: VecDeque::new(),
rpc_ready: false,
request_rx,
}
}
fn poll_rpc(&mut self, client: &mut Option<T>) -> Poll<(), ()> {
// This loop is make sure any streams that were found disconnected
// in `poll_destinations` while the `rpc` service is ready should
// be reconnected now, otherwise the task would just sleep...
loop {
if let Async::Ready(()) = self.poll_resolve_requests(client) {
// request_rx has closed, meaning the main thread is terminating.
return Ok(Async::Ready(()));
}
self.retain_active_destinations();
self.poll_destinations();
if self.reconnects.is_empty() || !self.rpc_ready {
return Ok(Async::NotReady);
}
}
}
fn poll_resolve_requests(&mut self, client: &mut Option<T>) -> Async<()> {
loop {
if let Some(client) = client {
// if rpc service isn't ready, not much we can do...
match client.poll_ready() {
Ok(Async::Ready(())) => {
self.rpc_ready = true;
},
Ok(Async::NotReady) => {
self.rpc_ready = false;
return Async::NotReady;
},
Err(err) => {
warn!("Destination.Get poll_ready error: {:?}", err);
self.rpc_ready = false;
return Async::NotReady;
},
}
// handle any pending reconnects first
if self.poll_reconnect(client) {
continue;
}
}
// check for any new watches
match self.request_rx.poll() {
Ok(Async::Ready(Some(resolve))) => {
trace!("Destination.Get {:?}", resolve.authority);
match self.destinations.entry(resolve.authority) {
Entry::Occupied(mut occ) => {
let set = occ.get_mut();
// we may already know of some addresses here, so push
// them onto the new watch first
match set.addrs {
Exists::Yes(ref cache) => for (&addr, meta) in cache {
let update = Update::Bind(addr, meta.clone());
resolve.responder.update_tx
.unbounded_send(update)
.expect("unbounded_send does not fail");
},
Exists::No | Exists::Unknown => (),
}
set.responders.push(resolve.responder);
},
Entry::Vacant(vac) => {
let pod_namespace = &self.namespaces.pod;
let query = client.as_mut().and_then(|client| {
Self::query_destination_service_if_relevant(
pod_namespace,
client,
vac.key(),
"connect",
)
});
let mut set = DestinationSet {
addrs: Exists::Unknown,
query,
dns_query: None,
responders: vec![resolve.responder],
};
// If the authority is one for which the Destination service is never
// relevant (e.g. an absolute name that doesn't end in ".svc.$zone." in
// Kubernetes), or if we don't have a `client`, then immediately start
// polling DNS.
if set.query.is_none() {
set.reset_dns_query(
&self.dns_resolver,
Instant::now(),
vac.key(),
);
}
vac.insert(set);
},
}
},
Ok(Async::Ready(None)) => {
trace!("Discover tx is dropped, shutdown");
return Async::Ready(());
},
Ok(Async::NotReady) => return Async::NotReady,
Err(_) => unreachable!("unbounded receiver doesn't error"),
}
}
}
/// Tries to reconnect next watch stream. Returns true if reconnection started.
fn poll_reconnect(&mut self, client: &mut T) -> bool {
debug_assert!(self.rpc_ready);
while let Some(auth) = self.reconnects.pop_front() {
if let Some(set) = self.destinations.get_mut(&auth) {
set.query = Self::query_destination_service_if_relevant(
&self.namespaces.pod,
client,
&auth,
"reconnect",
);
return true;
} else {
trace!("reconnect no longer needed: {:?}", auth);
}
}
false
}
/// Ensures that `destinations` is updated to only maintain active resolutions.
///
/// If there are no active resolutions for a destination, the destination is removed.
fn retain_active_destinations(&mut self) {
self.destinations.retain(|_, ref mut dst| {
dst.responders.retain(|r| r.is_active());
dst.responders.len() > 0
})
}
fn poll_destinations(&mut self) {
for (auth, set) in &mut self.destinations {
// Query the Destination service first.
let (new_query, found_by_destination_service) = match set.query.take() {
Some(Remote::ConnectedOrConnecting { rx }) => {
let (new_query, found_by_destination_service) =
set.poll_destination_service(
auth, rx, self.namespaces.tls_controller.as_ref().map(|s| s.as_ref()));
if let Remote::NeedsReconnect = new_query {
set.reset_on_next_modification();
self.reconnects.push_back(auth.clone());
}
(Some(new_query), found_by_destination_service)
},
query => (query, Exists::Unknown),
};
set.query = new_query;
// Any active response from the Destination service cancels the DNS query except for a
// positive assertion that the service doesn't exist.
//
// Any disconnection from the Destination service has no effect on the DNS query; we
// assume that if we were querying DNS before, we should continue to do so, and if we
// weren't querying DNS then we shouldn't start now. In particular, temporary
// disruptions of connectivity to the Destination service do not cause a fallback to
// DNS.
match found_by_destination_service {
Exists::Yes(()) => {
// Stop polling DNS on any active update from the Destination service.
set.dns_query = None;
},
Exists::No => {
// Fall back to DNS.
set.reset_dns_query(&self.dns_resolver, Instant::now(), auth);
},
Exists::Unknown => (), // No change from Destination service's perspective.
}
// Poll DNS after polling the Destination service. This may reset the DNS query but it
// won't affect the Destination Service query.
set.poll_dns(&self.dns_resolver, auth);
}
}
/// Initiates a query `query` to the Destination service and returns it as
/// `Some(query)` if the given authority's host is of a form suitable for using to
/// query the Destination service. Otherwise, returns `None`.
fn query_destination_service_if_relevant(
default_destination_namespace: &str,
client: &mut T,
auth: &DnsNameAndPort,
connect_or_reconnect: &str,
) -> Option<DestinationServiceQuery<T>> {
trace!(
"DestinationServiceQuery {} {:?}",
connect_or_reconnect,
auth
);
FullyQualifiedAuthority::normalize(auth, default_destination_namespace).map(|auth| {
let req = GetDestination {
scheme: "k8s".into(),
path: auth.without_trailing_dot().to_owned(),
};
let mut svc = Destination::new(client.lift_ref());
let response = svc.get(grpc::Request::new(req));
Remote::ConnectedOrConnecting {
rx: Receiver::new(response),
}
})
}
}

1
src/control/mod.rs
View File

@ -4,7 +4,6 @@ mod fully_qualified_authority;
mod observe; mod observe;
pub mod pb; pub mod pb;
mod remote_stream; mod remote_stream;
mod util;
pub use self::destination::Bind; pub use self::destination::Bind;
pub use self::observe::Observe; pub use self::observe::Observe;