Commit Graph

3 Commits

Author SHA1 Message Date
Oliver Gould 4e0a1f0100
refactor: Build stacks from bottom-to-top (#111)
Previously, stacks were built with `Layer::and_then`. This pattern
severely impacts compile-times as stack complexity grows.

In order to ameliorate this, `app::main` has been changed to build
stacks from the "bottom" (endpoint client) to "top" (serverside
connection) by _push_-ing Layers onto a concrete stack, i.e. and not
composing layers for an abstract stack.

While doing this, we take the oppportunity to remove a ton of
now-unnecessary `PhantomData`. A new, dedicated `phantom_data` stack
module can be used to aid type inference as needed.

Other stack utilities like `map_target` and `map_err` have been
introduced to assist this transition.

Furthermore, all instances of `Layer::new` have been changed to a free
`fn layer` to improve readability.

This change sets up two upcoming changes: a stack-oriented `controller`
client and, subsequently, service-profile-based routing.
2018-10-29 14:02:42 -07:00
Oliver Gould 2109f37531
Make a generic Watch stack (#104)
The TLS-configuration-watching logic in `app::outbound::tls_config` need
not be specific to the outbound types, or even TLS configuration.

Instead, this change extends the `watch` stack module with a Stack type
that can satisfy the TLS use case independently of the concrete types at
play.
2018-10-26 13:30:09 -07:00
Oliver Gould 978fed1cf6
refactor: Structure the proxy in terms of `Stack` (#100)
As the proxy's functionality has grown, the HTTP routing functionality
has become complex. Module boundaries have become ill-defined, which
leads to tight coupling--especially around the `ctx` metadata types and
`Service` type signatures.

This change introduces a `Stack` type (and subcrate) that is used as the
base building block for proxy functionality. The `proxy` module now
exposes generic components--stack layers--that are configured and
instantiated in the `app::main` module.

This change reorganizes the repo as follows:
- Several auxiliary crates have been split out from the `src/` directory
  into `lib/fs-watch`, `lib/stack` and `lib/task`.
- All logic specific to configuring and running the linkerd2 sidecar
  proxy has been moved into `src/app`. The `Main` type has been moved
  from `src/lib.rs` to `src/app/main.rs`.
- The `src/proxy` has reusable, generic components useful for building
  proxies in terms of `Stack`s.

The logic contained in `lib/bind.rs`, pertaining to per-endpoint service
behavior, has almost entirely been moved into `app::main`.

`control::destination` has changed so that it is not responsible for
building services. (It used to take a clone of `Bind` and use it to
create per-endpoint services). Instead, the destination service
implements the new `proxy::Resolve` trait, which produces an infinite
`Resolution` stream for each lookup. This allows the `proxy::balance`
module to be generic over the servie discovery source.

Furthermore, the `router::Recognize` API has changed to only expose a
`recgonize()` method and not a `bind_service()` method. The
`bind_service` logic is now modeled as a `Stack`.

The `telemetry::http` module has been replaced by a
`proxy::http::metrics` module that is generic over its metadata types
and does not rely on the old telemetry event system. These events are
now a local implementation detail of the `tap` module.

There are no user-facing changes in the proxy's behavior.
2018-10-11 11:25:03 -07:00