app: Move retry types into the app-outbound crate (#1378)

The retry crate is hardcoded to use the `linkerd_app_core::dst::Route`
type as its target. This is inflexible, especially if we want to
reorganize the outbound stack to support things like header-based
overrides.

This change movers the retry layer into the outbound crate so that it
can be changed to use outbound-specific types.

No functional changes.

Author: olix0r

Cargo.lock

@@ -839,7 +839,6 @@ dependencies = [
  "linkerd-exp-backoff",
  "linkerd-http-classify",
  "linkerd-http-metrics",
- "linkerd-http-retry",
  "linkerd-identity",
  "linkerd-io",
  "linkerd-meshtls",
@@ -856,7 +855,6 @@ dependencies = [
  "linkerd-proxy-tcp",
  "linkerd-proxy-transport",
  "linkerd-reconnect",
- "linkerd-retry",
  "linkerd-service-profiles",
  "linkerd-stack",
  "linkerd-stack-metrics",
@@ -966,11 +964,13 @@ dependencies = [
  "hyper",
  "linkerd-app-core",
  "linkerd-app-test",
+ "linkerd-http-classify",
  "linkerd-http-retry",
  "linkerd-identity",
  "linkerd-io",
  "linkerd-meshtls",
  "linkerd-meshtls-rustls",
+ "linkerd-retry",
  "linkerd-tracing",
  "parking_lot",
  "pin-project",

linkerd/app/core/Cargo.toml

@@ -32,7 +32,6 @@ linkerd-error-respond = { path = "../../error-respond" }
 linkerd-exp-backoff = { path = "../../exp-backoff" }
 linkerd-http-classify = { path = "../../http-classify" }
 linkerd-http-metrics = { path = "../../http-metrics" }
-linkerd-http-retry = { path = "../../http-retry" }
 linkerd-identity = { path = "../../identity" }
 linkerd-io = { path = "../../io" }
 linkerd-meshtls = { path = "../../meshtls", default-features = false }
@@ -49,7 +48,6 @@ linkerd-proxy-tap = { path = "../../proxy/tap" }
 linkerd-proxy-tcp = { path = "../../proxy/tcp" }
 linkerd-proxy-transport = { path = "../../proxy/transport" }
 linkerd-reconnect = { path = "../../reconnect" }
-linkerd-retry = { path = "../../retry" }
 linkerd-service-profiles = { path = "../../service-profiles" }
 linkerd-stack = { path = "../../stack" }
 linkerd-stack-metrics = { path = "../../stack/metrics" }

linkerd/app/core/src/classify.rs

@@ -214,7 +214,7 @@ fn h2_error(err: &Error) -> String {
 // === impl Class ===
 
 impl Class {
-    pub(super) fn is_failure(&self) -> bool {
+    pub fn is_failure(&self) -> bool {
         matches!(
             self,
             Class::Default(SuccessOrFailure::Failure)

linkerd/app/core/src/lib.rs

@@ -41,7 +41,6 @@ pub mod errors;
 pub mod http_tracing;
 pub mod metrics;
 pub mod proxy;
-pub mod retry;
 pub mod serve;
 pub mod svc;
 pub mod telemetry;

linkerd/app/outbound/Cargo.toml

@@ -19,8 +19,10 @@ bytes = "1"
 http = "0.2"
 futures = { version = "0.3", default-features = false }
 linkerd-app-core = { path = "../core" }
+linkerd-http-classify = { path = "../../http-classify" }
 linkerd-http-retry = { path = "../../http-retry" }
 linkerd-identity = { path = "../../identity" }
+linkerd-retry = { path = "../../retry" }
 parking_lot = "0.11"
 thiserror = "1.0"
 tokio = { version = "1", features = ["sync"] }

linkerd/app/outbound/src/http.rs

@@ -3,6 +3,7 @@ mod endpoint;
 pub mod logical;
 mod proxy_connection_close;
 mod require_id_header;
+mod retry;
 mod server;
 mod strip_proxy_error;
 

linkerd/app/outbound/src/http/logical.rs

@@ -1,4 +1,4 @@
-use super::{CanonicalDstHeader, Concrete, Endpoint, Logical};
+use super::{retry, CanonicalDstHeader, Concrete, Endpoint, Logical};
 use crate::{endpoint, resolve, stack_labels, Outbound};
 use linkerd_app_core::{
     classify, config, dst, profiles,
@@ -8,7 +8,7 @@ use linkerd_app_core::{
         http,
         resolve::map_endpoint,
     },
-    retry, svc, Error, Infallible,
+    svc, Error, Infallible,
 };
 use tracing::debug_span;
 

linkerd/app/core/src/retry.rs renamed to linkerd/app/outbound/src/http/retry.rs

@@ -1,15 +1,17 @@
-use super::classify;
-use super::dst::Route;
-use super::http_metrics::retries::Handle;
-use super::metrics::HttpRouteRetry;
-use crate::profiles;
 use futures::future;
-use linkerd_error::Error;
+use linkerd_app_core::{
+    classify,
+    dst::Route,
+    http_metrics::retries::Handle,
+    metrics::HttpRouteRetry,
+    profiles,
+    proxy::http::{ClientHandle, HttpBody},
+    svc::{layer, Either, Param},
+    Error,
+};
 use linkerd_http_classify::{Classify, ClassifyEos, ClassifyResponse};
 use linkerd_http_retry::ReplayBody;
-use linkerd_proxy_http::ClientHandle;
 use linkerd_retry as retry;
-use linkerd_stack::{layer, Either, Param};
 use std::sync::Arc;
 
 pub fn layer<N>(
@@ -60,7 +62,7 @@ impl retry::NewPolicy<Route> for NewRetryPolicy {
 
 impl<A, B, E> retry::Policy<http::Request<ReplayBody<A>>, http::Response<B>, E> for RetryPolicy
 where
-    A: http_body::Body + Unpin,
+    A: HttpBody + Unpin,
     A::Error: Into<Error>,
 {
     type Future = future::Ready<Self>;
@@ -125,7 +127,7 @@ where
 
 impl<A, B, E> retry::PrepareRequest<http::Request<A>, http::Response<B>, E> for RetryPolicy
 where
-    A: http_body::Body + Unpin,
+    A: HttpBody + Unpin,
     A::Error: Into<Error>,
 {
     type RetryRequest = http::Request<ReplayBody<A>>;