* trace-core: Pass dispatcher by ref to `dispatcher::with_default`
As requested by @carllerche in https://github.com/tokio-rs/tokio/pull/966#discussion_r264380005, this branch changes the
`dispatcher::with_default` function in `tokio-trace-core` to take the
dispatcher by ref and perform the clone internally. This makes this
function more consistant with other `with_default` functions in other
crates.
Signed-off-by: Eliza Weisman <[email protected]>
* trace: Don't set the default dispatcher on entering a span
Setting the default dispatcher on span entry is a relic of when spans
tracked their parent's ID. At that time, it was necessary to ensure that
any spans created inside a span were observed by the same subscriber
that originally provided the entered span with an ID, as otherwise, new
spans would be created with parent IDs that did not originate from that
subscriber.
Now that spans don't track their parent ID, this is no longer necessary.
However, removing this behavior does mean that if a span is entered
outside of the subscriber context it was created in, any subsequent
spans will be observed by the current default subscriber and thus will
not be part of the original span's trace tree. Since subscribers are not
expected to change frequently, and spans are not expected to move
between them, this is likely acceptable.
I've removed the tests for the old behavior.
Note that this change improves the performance of span entry/exit fairly
significantly. Here are the results of running a benchmark that enters
a span, does nothing, and immediately exits it, before this change:
```
test enter_span ... bench: 93 ns/iter (+/- 14)
```
...and after:
```
test enter_span ... bench: 51 ns/iter (+/- 9)
```
Signed-off-by: Eliza Weisman <[email protected]>
## Motivation
Currently, it isn't possible to import individual macros from
`tokio-trace` using the macros 1.2 syntax:
```rust
use tokio_trace::{debug, info, span};
```
This is because these macros require that `callsite` and `enabled` are
imported as well.
## Solution
This branch resolves the problem by adding the [`local_inner_macros`]
attribute to the instrumentation API's macros. This allows other macros
from within the crate to be used without requiring them to be explicitly
imported.
However, this also requires duplicating any macros from other sources
(such as std and `tokio-trace-core`) with wrappers due to the behaviour
of `local_inner_macros`. I've added these wrapper macros as well.
Since the macros got even longer as a result of this, I've moved them
to a separate file to make `lib.rs` easier to read. I've also wrapped
some very long lines in the macros, and removed the explicit drop of
the result of evaluating some event macros (it's no longer necessary
as all event macros now evaluate to `()`).
[`local_inner_macros`]: https://doc.rust-lang.org/nightly/edition-guide/rust-2018/macros/macro-changes.html#local-helper-macrosFixes#968
Signed-off-by: Eliza Weisman <[email protected]>
This branch makes a handful of `tokio-trace-core` API improvements, mostly
around naming. In particular:
* Rename `dispatcher::with` to `dispatcher::get_default`
* Rename `Event::observe` to `Event::dispatch`
* Make `field::ValidLen` trait private
Closes#948Closes#960
Signed-off-by: Eliza Weisman <[email protected]>
This branch changes the `Subscriber::record` method to take a new
arguments struct, `span::Record`. The `field::Record` trait was renamed
to `field::Visit` to prevent name conflicts.
In addition, the `ValueSet::is_empty`, `ValueSet::contains`, and
`ValueSet::record` methods were made crate-private, as they are exposed
on the `Attributes` and `Record` types.
Signed-off-by: Eliza Weisman <[email protected]>
This branch allows users of `tokio-trace` to explicitly set a span's
parent, or indicate that a span should be a new root of its own trace
tree. A `parent: ` key has been added to the `span!` macros. When a span
is provided, that span will be set as the parent, while `parent: None`
will result in a new root span. No `parent:` key results in the current
behaviour.
A new type, `span::Attributes`, was added to `tokio-trace-core` to act
as an arguments struct for the `Subscriber::new_span` method. This will
allow future fields to be added without causing breaking API changes.
The `Attributes` struct currently contains the new span's metadata,
`ValueSet`, and parent.
Finally, the `span::Span` type in `-core` was renamed to `span::Id`, for
consistency with `tokio-trace` and to differentiate it from
`span::Attributes`. This name was chosen primarily due to precedent in
other tracing systems.
Closes#920
Signed-off-by: Eliza Weisman <[email protected]>
A single-producer, multi-consumer channel that only retains the _last_ sent
value. Values are broadcasted out.
This channel is useful for watching for changes to a value from multiple
points in the code base (for example, changes to a configuration value).
- Rewrite noop_waker with items from the new API and replaces
LocalWaker with Waker.
- Bump the minimum required version for `tokio-async-await` to
1.34.0-nightly.
- `Unpin` was added to std prelude.
- Add `cargo check` to .travis.yml
Fixes: #908
This branch adds links to the master RustDoc published by CI to the
`tokio-trace` and `tokio-trace-core` README. In addition, it fixes a
broken links in the RustDoc for `tokio-trace` and updates the
`tokio-trace-core` RustDoc to match the README.
Signed-off-by: Eliza Weisman <[email protected]>
## Motivation
As described in #905, subscribers have no way to get the numeric value of a span ID back _out_ of a `Span`.
## Solution
Add a `Span::into_u64` method that returns the inner `u64` span ID
Closes#905
Signed-off-by: kleimkuhler <[email protected]>
In order to support nesting a tokio reactor within another event
system exposing the file descriptor for the underlying reactor
is useful and is already implemented for mio::Poll.
Signed-off-by: Paul Osborne <[email protected]>
This patch fixes Semaphore by adding a missing code path to the release
routine that handles the case where the waiter's node is queued in the
sempahore but has not yet been assigned the permit.
This fix is used by mpsc to handle the case when the Sender has called
`poll_ready` and is dropped before the permit is acquired.
Fixes#900
This change adds an extension trait to `BufStream` and puts the core
trait behind a feature flag for optional use.
This mainly adds the additional functions in an extension trait to
allow the user to select if they want just the core trait or the fully
featured version. Now the user can add the core feature to _not_
include the extension trait. By deafult, this feature is disabled.
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Bug fixes and new features should include tests.
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## Motivation
In asynchronous systems like Tokio, interpreting traditional log
messages can often be quite challenging. Since individual tasks are
multiplexed on the same thread, associated events and log lines are
intermixed making it difficult to trace the logic flow. Currently, none
of the available logging frameworks or libraries in Rust offer the
ability to trace logical paths through a futures-based program.
There also are complementary goals that can be accomplished with such a
system. For example, metrics / instrumentation can be tracked by
observing emitted events, or trace data can be exported to a distributed
tracing or event processing system.
In addition, it can often be useful to generate this diagnostic data in
a structured manner that can be consumed programmatically. While prior
art for structured logging in Rust exists, it is not currently
standardized, and is not "Tokio-friendly".
## Solution
This branch adds a new library to the tokio project, `tokio-trace`.
`tokio-trace` expands upon logging-style diagnostics by allowing
libraries and applications to record structured events with additional
information about *temporality* and *causality* --- unlike a log
message, a span in `tokio-trace` has a beginning and end time, may be
entered and exited by the flow of execution, and may exist within a
nested tree of similar spans. In addition, `tokio-trace` spans are
*structured*, with the ability to record typed data as well as textual
messages.
The `tokio-trace-core` crate contains the core primitives for this
system, which are expected to remain stable, while `tokio-trace` crate
provides a more "batteries-included" API. In particular, it provides
macros which are a superset of the `log` crate's `error!`, `warn!`,
`info!`, `debug!`, and `trace!` macros, allowing users to begin the
process of adopting `tokio-trace` by performing a drop-in replacement.
## Notes
Work on this project had previously been carried out in the
[tokio-trace-prototype] repository. In addition to the `tokio-trace` and
`tokio-trace-core` crates, the `tokio-trace-prototype` repo also
contains prototypes or sketches of adapter, compatibility, and utility
crates which provide useful functionality for `tokio-trace`, but these
crates are not yet ready for a release. When this branch is merged, that
repository will be archived, and the remaining unstable crates will be
moved to a new `tokio-trace-nursery` repository. Remaining issues on the
`tokio-trace-prototype` repo will be moved to the appropriate new repo.
The crates added in this branch are not _identical_ to the current head
of the `tokio-trace-prototype` repo, as I did some final clean-up and docs
polish in this branch prior to merging this PR.
[tokio-trace-prototype]: https://github.com/hawkw/tokio-trace-prototypeCloses: #561
Signed-off-by: Eliza Weisman <[email protected]>
ATOMIC_BOOL_INIT is deprecated since 1.34 because the const fn
AtomicUsize::new is now preferred. As deny(warnings) is set,
tokio fails to build on latest nightly. This will fix it.
Signed-off-by: Yilin Chen <[email protected]>
Eliza Weisman