## Motivation
The `tracing` crate implements scoped, structured, context-aware
diagnostics, which can add significant debugging value over unstructured
log messages. `tracing` is part of the Tokio project. As part of the
`tokio` 0.2 changes, I thought it would be good to move over from `log`
to `tracing` in the tokio runtime. Updating the executor crate is an obvious
starting point.
## Solution
This branch replaces the use of `log` in `tokio-executor` with
`tracing`. I've tried to leave all the instrumentation points more or
less the same, but modified to use structured fields instead of string
interpolation. I've also added a few `tracing` spans, primarily in
places where a variable is added to all the log messages in a scope.
## Notes
For users who are using the legacy `log` output, there is a feature flag
to enable `log` support in `tracing`. I thought about making this on by
default, but that would also enable the `tracing` dependency by default,
and it is only pulled in when the `threadpool` feature flag is enabled.
The `tokio` crate could enable the log feature in its default features
instead, since the threadpool feature is on by default in `tokio`. If
this isn't the right approach, I can change how `log` back-compatibility
is enabled.
We might want to consider adding more `tracing` spans in the threadpool
later. This could be useful for profiling, and for helping users debug
the way their applications interact with the executor. This branch is
just intended as a starting point so that we can begin emitting
`tracing` data from the executor; we should revisit what instrumentation
should be exposed, as well.
Signed-off-by: Eliza Weisman <[email protected]>
We want executors to enforce that there are never multiple active at the
same time. This is ensured through `Enter`, which will panic if you
attempt to create more than one. However, by requiring you to pass an
`&mut Enter` to `executor::with_default`, we were *also* disallowing
temporarily overriding the current executor.
This patch removes that requirement.
A first pass at updating Tokio to use `std::future`.
Implementations of `Future` from the futures crate are updated to implement
`Future` from std. Implementations of `Stream` are moved to a feature flag.
This commits disables a number of crates that have not yet been updated.
Adds a `TypedExecutor` trait that describes how to spawn futures of a specific
type. This is useful for implementing functions that are generic over an executor
and wish to support both `Send` and `!Send` cases.
This also bumps a number of sub crates:
* tokio-executor (0.1.3)
* tokio-io (0.1.8)
* tokio-reactor (0.1.4)
* tokio-threadpool (0.1.6)
* tokio-timer (0.2.6)
* tokio-udp (0.1.2)
The futures 0.2 crate is not intended for widespread usage. Also, the
futures team is exploring the compat shim route.
If futures 0.3 support is added to Tokio 0.1, then a different
integration route will be explored, making the current code unhelpful.
* Normalize links to docs.rs/CRATE/M.N/...
docs.rs is smart enough to show docs for the latest M.N.P release when
M.N is used in the link. For example:
https://docs.rs/mio/0.6/mio/struct.Poll.html
..will show mio 0.6.14 and later docs. While using the `M.N.*`
(ASTERISK) syntax also works, `M.N` is the more common usage, so
standarize a few existing links to that format.
* Fix missing or malformed rustdoc links
* executor lib rustdoc minor format change
* Promote tokio-threadpool crate level comments to rustdoc
* Replace hidden tokio::executor::thread_pool docs with deprecation note
* Fix typo/simplify util module rustdoc
* Reuse some tokio::executor::thread_pool rustdoc for the crate
Relates to #421
Taiki Endo